MSC Software Corporation

1993-1999 MSC Users' Conference Proceedings

Elements
Fatigue Analysis
General Stress Analysis
Interfaces to MSC/NASTRAN
MSC/DYTRAN & MSC/FATIGUE
MSC/NASTRAN Applications
MSC/NASTRAN & MSC/PATRAN
MSC/PATRAN & Other MSC Products

Design/Manufacturing Methods

APPLYING MSC/PATRAN AND MSC/NASTRAN TO IMPROVE THE DESIGN PERFORMANCE OF LARGE BULK MATERIALS HANDLING MACHINES (Acrobat 33K) #3798, 9 pgs. R.C. Morgan, Dr. S. Loganathan, and Dr. F. Gatto--BHP Engineering Pty Ltd. ABSTRACT: Bulk materials handling machines such as stackers, bucket wheel reclaimers, ship loaders and ship unloaders are complex moving structures with onerous loading and service conditions. Due to such factors there is the potential for many failure modes and problem areas on these machines. Machines are normally purpose designed for the particular application at a port, mine or industrial facility. In the current environment, high reliability standards are required in order to provide operational security for business and safety to personnel. Dynamic, buckling and non linear behaviour of such structures can all contribute to failures and operational problems. Hence a sophisticated analysis and modelling tool is required in order to provide adequate representation under service conditions. Due to the complexity and size of these structures, models with large numbers of degrees of freedom are required for analysis. It was previously very time consuming and costly to carry out such work, putting it out of the realms of commercial application. However the compatibility of MSC/PATRAN with CAD systems and the ease of building large models, together with recent developments in the efficiency of the solvers in MSC/NASTRAN, opens new frontiers for engineers to critically examine the design of new structures before they are built. Similarly, with the application of MSC/PATRAN and MSC/NASTRAN, existing machines can be critically examined and cost effective life extension strategies developed to deliver major economic benefits to owners. COMBINING MSC/NASTRAN, SENSITIVITY METHODS AND VIRTUAL REALITY TO FACILITATE INTERACTIVE DESIGN (Acrobat 819K) #395, 11 pgs. Tsung-Pin Yeh--Iowa State University Judy M. Vance--Iowa State University

ABSTRACT: This paper will present results of a research project which investigated incorporating finite element analysis results into a virtual environment. Three programs developed in the course of this research are described. MSC/NASTRAN is used to perform the analysis and WorldToolKit and GL are used to develop the virtual environment. Virtual reality peripherals including a head-mounted display and a BOOM are used with a 3D mouse as interface devices. Sensitivity methods are incorporated into the programs to allow the designer to change design variables and immediately view the effects without performing a re-analysis.
AN INTRODUCTION TO TOLERANCE ANALYSIS OF FLEXIBLE ASSEMBLIES (Acrobat 256K) 1996, 14 pgs. K. G. Merkley--Brigham Young University K. W. Chase--Brigham Young University E. Perry--Brigham Young University

ABSTRACT

MODELING OF DIE SURFACE FEATURES ON INTEGRATED CIRCUITS TO IMPROVE DEVICE RELIABILITY (Acrobat 1.9MB) 1996, 14 pgs. John Sauber--Digital Equipment Corporation

ABSTRACT

RAPID OPTO-MECHANICAL DESIGN USING PRO/E, MSC/NASTRAN AND CODE V. (Acrobat 683K) #2198, 10 pgs.
Victor J. Wagner, Richard Malnory, and K. Scott. Ellis--Raytheon Missile Systems Company

ABSTRACT: The mechanical design of Optical systems (Opto-Mechanical Design) is typically concerned with minimizing the impact of the mechanical structure and environments on optical performance. Structurally insignificant loads may induce unacceptable motion and/or distortion into the optical elements, which are summed along the optical path resulting in total image blur and error. Optical system designs are therefore extremely sensitive to mounting configurations and structural dynamic characteristics of the mechanical system. A process for efficient design investigation is discussed that provides rapid system and individual optical element error predictions for mechanical system design. Topics include discussions of fundamental Opto-Mechanical design considerations, Pro/E model modification to facilitate automesh techniques, various automesh approaches using MSC/PATRAN and Pro/Engineer, tet4 vs tet10 element performance and accuracy with MSC/NASTRAN, Line Of Sight (LOS) error predictions, and Zernike polynomial calculations for optical surface aberrations using the MSC/OPOLY utility and Code V.

RECENT ADVANCES IN MSC/PATRAN PRE-PROCESSING SOFTWARE ALLOWS MODELING OF COMPLEX AUTOMOTIVE LAMP DESIGNS (Acrobat 618K) #3398, 9 pgs. William I. Moore, Eric S. Donovan, and Christopher R. Powers-- Delphi Interior and Lighting Systems

ABSTRACT: Advances in automotive lamp designs have resulted in a more compact, aerodynamic packaging and the use of less expensive plastic materials for the lens and housing. The smaller packaging and lower melting point of plastics have increased the need for a predictive tool for simulating the lamp temperature rise under operating conditions. The modeling of lamps requires sophisticated analysis tools incorporating computational fluid dynamics and specular radiation. These tools use a finite element method to solve a system of non-linear equations for velocity, pressure and temperature. In addition to the non-linearity, the complex parabolic shape of the lamp reflector and lens requires very powerful mesh generation capability in order to produce an adequately refined mesh. The lamp modeling is performed in two stages. First the model is generated by importing CAD data from Pro/ENGINEER or Unigraphics into the MSC/PATRAN pre-processor. The surfaces are then meshed with triangular elements which are used as a seed for creating the air volume and lamp solid wall tetrahedral element meshes. The use of the new MSC/PATRAN hybrid tetrahedral mesher has enabled the creation of very complex 3D element meshes to represent fluid volumes with several hundred thousand elements. MSC/PATRAN has become a common pre/post-processor for many analysis codes because of the open CAE environment, advanced meshing capability, ease of applying loads and boundary conditions and effective post-processing capability for displaying results.

DMAP Applications

A DMAP ALTER TO ALLOW AMPLITUDE-DEPENDENT MODAL DAMPING IN A TRANSIENT SOLUTION (Acrobat 224K) 1996, 15 pgs. Ted Rose--The MacNeal-Schwendler Corporation Martin McNamee--The MacNeal-Schwendler Corporation

ABSTRACT

A DMAP alter is presented which allows the user to include modal damping which is a function of the displacement (or velocity) measured at selected points.

DMAP ALTERS FOR CALCULATING AND SUMMARIZING RESULTANT FORCES FROM THE APPLICATION OF SPC AND AUTOSPC CONSTRAINTS (Acrobat 983K) #0994, 18 pgs. Grant Parker -- Northrop Corporation John Brown -- Northrop Corporation Ted Rose -- The MacNeal-Schwendler Corporation Jim Swan -- The MacNeal-Schwendler Corporation

ABSTRACT:

Discussion and examples of the use of the DMAPs for model verification are presented.

MSC/NASTRAN BASED COMPONENT MODE SYNTHESIS ANALYSIS WITHOUT THE USE OF DMAPS (Acrobat 64K) 1996, 19 pgs. Tarun Ghosh--Rockwell International Corporation

STIFFNESS-GENERATED RIGID-BODY MODE SHAPES FOR LANCZOS EIGENSOLUIION WITH SUPORT DOF VIA A MSC/NASTRAN DMAP ALTER (Acrobat 694K) #1094, 16 pgs.
Ayman A. Abdallah -- Analex Corporation
Alan R Barnett -- Analex Corporation
Timothy W. Widrick -- Analex Corporation
Richard T Manella -- National Aeronautics and Space Administration
Robert P. Miller -- National Aeronautics and Space Administration

ABSTRACT:

TRANSIENT ANALYSIS MODE PARTICIPATION FOR MODAL SURVEY TARGET MODE SELECTION USING MSC/NASTRAN DMAP (Acrobat 1.14MB) #0894, 19 pgs. Alan R. Bamett -- Analex Corporation Omar M. Ibrahim -- Analex Corporation Timothy L. Sullivan -- Analex Corporation Thomas W. Goodnight -- National Aeronautics and Space Administration

ABSTRACT

DMAP in Dynamics

EFFECTIVE MASS SENSITIVITY: A DMAP PROCEDURE (Acrobat 743K) #3995, 18 pgs. A. Bramante--Alenia Spazio A. Paolozzi--Universita' degli Studi di Roma "La Sapienza" I. Peroni--Universita' degli Studi di Roma "La Sapienza"

ABSTRACT:

A GENERAL PROCEDURE FOR FINITE ELEMENT MODEL CHECK AND MODEL IDENTIFICATION (Acrobat 1.39MB) #3895, 18 pgs. Y T Chung----McDonnell Douglas Aerospace Company - West L. L. Kahre--McDonnell Douglas Aerospace Company - West

ABSTRACT

A STAND-ALONE DMAP PROGRAM FOR MODAL CROSS-CORRELATION (Acrobat 564K) #4095, 10 pgs. Jack Scanlon--Analex Corporation
Jim Swan--MacNeal-Schwendler Corporation

ABSTRACT: A standalone DMAP program has been developed which gives the MSC/NASTRAN analyst a more complete set of tools with which to address the task of modal cross-correlation analysis. This program brings a number of user-oriented features to the otherwise fairly simple [phi]<sup>T[M] [phi] calculations. These features include options for reducing and realigning the DOFs between the two models (manual or automatic), re-ordering and/or removing modes, and several normalizing and filtering options. The program has been tested and used with both simple test models and real-world models. The paper briefly explains modal cross correlation and discusses the tools that this DMAP brings for both pre-processing of the input matrices and post-processing of the results.

Durability

FATIGUE LIFE ANALYSIS OF VOLVO S80 BI-FUEL (Acrobat 195K) #0499, 7 pgs.
M. Fermér, G. McInally and G. Sandin--Volvo Car Corporation, Sweden

ABSTRACT: The dimensioning of Volvo S80 Bi-Fuel has been totally performed in a virtual environment. Several design solutions have been numerically investigated using two dominant load cases. The robustness of chosen solutions have been investigated by calculations with critical spotwelds removed from the FE-model. The final design has been verified with a full four poster shake rig test. Although the rear floor is totally redesigned for the gas tank installation, no fatigue failure has been observed in this area.
The paper gives some insight into the dimensioning process, with special focus on spotweld fatigue analysis. All fatigue calculations were performed using MSC/Fatigue.

FE-BASED WHEEL FATIGUE ANALYSIS USING MSC.FATIGUE (Acrobat 130 K) #0599, 5 pgs.
S.C. Kerr and N.W.M. Bishop--MSC.Software, UK
D.L. Russell and U.S. Patel--BF Goodrich Aerospace, OH

ABSTRACT: A validation exercise is currently underway at BF Goodrich to evaluate the fatigue life of a rotating wheel using a new "WHEELS" capability within MSC.FATIGUE. BF Goodrich will shortly be using this capability to automate fatigue calculations for rotating aircraft wheels subject to vertical and lateral loads. As part of a validation exercise, an FE model of the wheel was analysed by applying a bearing roller load around the inner surface of the wheel hub at 15 ^o increments. A linear static analysis was conducted at each increment to produce a stress tensor history ( s_x, s_y, and t_xy) for all surface nodes. Due to the nature of a rolling wheel, it was expected that the principal stresses and their directions would vary for each increment. For this reason, the stress tensors were also rotated on the model surface through 360 ^o, at 10 ^o increments, to calculate the components of the principal stresses in those directions. All stress data was run through an S-N fatigue life analysis with no mean stress correction. Although not complete, the results are expected to show contour plots of fatigue life and fatigue damage for all nodes at the worst (most damaging) surface angle. MSC.Software envisions that this new capability can also be applied to any rotating body, especially automotive wheels.

THE IGNORED FAILURE MODE: SPOTWELD UNDER INPLANE ROTATION (Acrobat 683K) #0399, 11 pgs.
Pey Wung--Ford Motor Company, USA

ABSTRACT: Spot weld failures of complicated structure, such as automobile bodies, are difficult to explain using current multiaxial spot weld failure theory. After introducing the in-plane rotational failure mode, some unexplainable spot weld failures become explainable. The purpose of this report is to introduce the spot weld rotational test, its relative strengths and its finite element simulation. It is found that the strength of a spot weld under the in-plane rotational mode is far below the strengths of the same spot weld under other failure modes such as in-plane shear. Hence, the work conducted in this study could be a foundation for a new generation of multiaxial spot weld failure theory development.

USING MSC.Fatigue TO ESTIMATE THE FATIGUE DAMAGE CAUSED TO VIBRATING AUTOMOTIVE COMPONENTS (NOT PRESENTED) (Acrobat 650K) #3899, 7 pgs.
Neil Bishop, Stuart Kerr, and Alan Caserio--MSC.Software

ABSTRACT: An earlier paper demonstrated that vibration fatigue techniques can be a powerful tool in the design of automotive components subjected to vibration loadings. This paper extends the work by utilizing new techniques in the software program MSC.Fatigue. In particular, new techniques now exist which enable principal stresses to be computer over the entire surface region of interest. Complete results are included in this paper.
Vibration testing of components using accelerated test tracks or laboratory simulators is widely used in automotive design, as is fatigue testing for reliability. Furthermore, there are many common features between these two disciplines. However, problems often arise when engineers who are skilled in one field have to use techniques and concepts more generally used in the other. One example of such a situation concerns the use of frequency domain descriptions of structural response, which are commonplace in vibration. Many engineering applications, such as offshore structures and wind turbines, have already seen the benefits of using frequency domain fatigue analysis for reliability assessment. The purpose of this paper is to assess the benefits of frequency domain fatigue analysis and compare it with more conventional time domain techniques. A typical automotive component has been analyzed using MSC.Nastran and MSC.Fatigue using both time and frequency domain methods. Probability density functions and fatigue lives computed using output from these two different approaches show good agreement.

USING THE MSC/NASTRAN SUPERELEMENT MODAL METHOD TO IMPROVE THE ACCURACY OF PREDICTIVE FATIGUE LOADS OF A SHORT AND LONG ARM TYPE REAR SUSPENSION (Acrobat 228 K) #0699, 24 pgs.
Dr. Hong Zhu, Dr. John Dakin and Ray Pountney--Ford Motor Company Limitd

ABSTRACT: In the fiercely competitive world of today's automotive industry, Computer Aided Engineering (CAE) is playing a more and more important role in shortening the design cycle time, minimising costs and improving the product quality.
For vehicle engineering, an optimised design is to develop a light-weight, safe and durable system. A key aspect of the fatigue/durability process is to quantify the vehicle service loads in the early design phase. Within the constraints of the development time, cost and quality, the trend has been to reduce road measurement, to use more rig simulation, to increase CAE prototypes and to decrease hardware prototypes. The accuracy of the CAE durability process is mandated to achieve a robust design.
This investigation includes an application of the MSC/Nastran superelement modal method to improve the load accuracy of a short and long arm typed rear suspension. Also a comparison is made between the loads obtained using rigid body dynamics and those including MSC/Nastran flexible bodies and to quantify the influence of the elastic suspension components such as links and knuckles.
Rigid body dynamic simulation methods usually neglect the flexibility and the modal properties of the elastic components. An integration of the MSC/Nastran superelement modal method with the MDI/Adams rigid body dynamics method offers an effective tool to improve the quality of the prediction of dynamic fatigue loads in the new product development.

VIBRATION FATIGUE ANALYSIS IN THE FINITE ELEMENT ENVIRONMENT (NOT PRESENTED) (Acrobat 1.3 MB) #3799, 16 pgs.
Neil Bishop--MSC.Software Limited-United Kingdom

ABSTRACT: Fatigue damage is traditionally determined from time signals of loading, usually in the form of stress or strain. However, there are many design scenarios when the loading, or fatigue damage process, cannot easily be defined using time signals. In these cases the design engineer usually has to use a test based approach to evaluate the fatigue life of his structure or component. Or, alternatively, a frequency based fatigue calculation can be utilised where the loading and response are represented using Power Spectral Density (PSD) functions. One very important design problem, which falls into this category, is that of acoustic fatigue. However, there are also many other situations where structures are subjected to a random form of loading such as wing flutter, landing gear runway profiles, engine vibrations and so on. All of these situations can be analysed using new fatigue life estimation techniques now incorporated into the Finite Element Analysis (FEA) environment.
The theory of random vibration fatigue has seen a number of important developments over the last fifteen years. The author has been personally involved in developing new fatigue analysis theories and structural analysis techniques in the frequency domain. More recently this work has focused on the link with FEA because of the powerful design opportunities which this creates. The work has found many important practical applications. This paper presents a state of the art perspective of random vibration fatigue technology and FEA based fatigue analysis. A number of design applications are presented.

Dynamics

APPLICATION OF APPROXIMATE TECHNIQUES IN THE ESTIMATION OF EIGENVALUE QUALITY (Acrobat 582K) #1193, 18 pgs.
B. P. Wang -- The University of Texas at Arlington
S. P. Caldwell -- McDonnell Douglas Corporation

ABSTRACT:

APPLICATION OF MSC/DYNA IN HEAD IMPACT ANALYSIS (Acrobat 205K) #7093, 6 pgs.
Vasudeva Murthy -- Johnson Controls
Han Sankara -- Johnson Controls

ABSTRACT: The Federal Motor Vehicle Safety Standard 201 (FMVSS 201) specifies requirements to afford impact protection for occupants. It provides (see reference 1) that "when that area of the seat back that is impacted in accordance with S3.22 by a 15 pound, 6.5 inches diameter head-form at a relative velocity of 15 mph the deceleration of the head-form shall not exceed 80 g's for more than 3 ms". This paper presents the results of a head impact simulation on an automotive seat using MSC/DYNA. The results were correlated with those from an actual laboratory test. Good correlation was achieved in the deceleration time history as well as deformation of the structure. Though simulations of the crash type have been performed on entire vehicles few have been focussed on the seat to the level of detail here.

DEVELOPMENT OF A CALCULATION PROCEDURE INCLUDING FLUID STRUCTURE COUPLING TO ASSESS CAVITATION EFFECTS (Acrobat 982K) #6993, 15 pgs.
Gotthard Ph. Rainer -- AVL - Company for Internal Combustion Engines and Instrumentation Ltd.
Ernst Gschweitl -- AVL - Company for Internal Combustion Engines and Instrumentation Ltd.
Hans Christoph Raffel -- AVL - Company for Internal Combustion Engines and Instrumentation Ltd.

ABSTRACT: Between cylinder liner and parent bore of internal combustion engines cooling water flow is existing.

Due to the operating conditions cavitation effected by

dynamic acoustic excitations and
fluid flow may occur.

AVL is investigating both effects using the MSC/NASTRAN acoustic element to consider the dynamic acoustic effected cavitation and the AVL developed CFD-software FIRE for the fluid flow effects.

This paper considers only the dynamic acoustic effect. Here the calculational and experimental work is explained, which has been done till now to apply MSC/NASTRAN to cavitation calculation. In addition to this, the difficulties to per form measurements and to compare the results out of calculation and of measurements are described.

The MAC (Modal Accuracy Criterion) is used as a tool to compare measurement and calculation. The calculations are carried out as eigenmode analysis and as forced vibrations.

AN EQUIVALENT LINEARIZATION SOLUTION SEQUENCE FOR MSC/NASTRAN (Acrobat 786K) #3593, 11 pgs.
J.H. Robinson -- NASA Langley Research Center
C.K. Chiang -- Old Dominion University

ABSTRACT:

EULER BUCKLING (Acrobat 434K) #6793, 17 pgs.
Kevin E. Arden -- Newport News Shipbuilding

ABSTRACT:

Column buckling, panel buckling, and stiffened panel buckling is analyzed using Euler equations and Solution 105. Comparisons and modeling recommendations are made for each type of structure.

Solution 105 provides excellent results for Euler type buckling. Panel buckling requires the use of an adequate number of elements. A convergence plot shows that four QUAD4 elements per half sine wave are necessary for accurate results.

The opinions expressed herein are those of the author and do not necessarily reflect those of Newport News Shipbuilding and Dry Dock Company.

IDENTIFICATION OF CRITICAL SPEEDS OF ROTORS ATTACHED TO FLEXIBLE SUPPORTS (Acrobat 333K) #3493, 7 pgs.
David Bella -- The MacNeal-Schwendler Corporation
Hans Hartmueller -- BMW Rolls-Royce GmbH
Dr. Karsten Muehlenfeld -- BMW Rolls-Royce GmbH
Dr. Gabriel Tokar -- BMW Rolls-Royce GmbH

ABSTRACT:

PSDTOOL - A DMAP ENHANCEMENT TO HARMONIC/RANDOM RESPONSE ANALYSIS IN MSC/NASTRAN (Acrobat 1.12MB) #3693, 25 pgs.
Alwar Parthasarathy -- Advanced Technology Systems Group, Spar Aerospace Limited
Mohamed Elzeki -- Advanced Technology Systems Group, Spar Aerospace Limited
Vivianne Abramovici -- Advanced Technology Systems Group, Spar Aerospace Limited

ABSTRACT:

PSDTOOL

harmonic/random response

response-maxima

base-motion PSD-spectrum

RMS

all the grid-points

single OLOAD-type table

peak RMS

subsystems

mass-weighted average- responses at 'centers-of-mass'

relative-motion

DBLOCATE-restart

SOLVING MODAL EQUATIONS OF MOTION WITH INITIAL CONDITIONS USING MSC/NASTRAN DMAP, PART 1: IMPLEMENTING EXACT MODE SUPERPOSITION (Acrobat 533K) #1293, 12 pgs.
Ayman A. Abdallah -- Analex Corporation
Alan R. Barnett -- Analex Corporation
Omar M. Ibrahim -- Analex Corporation
Richard T. Manella -- National Aeronautics and Space Administration

ABSTRACT:

SOLVING MODAL EQUATIONS OF MOTION WITH INITIAL CONDITIONS USING MSC/NASTRAN DMAP, PART 2: COUPLED VS. UNCOUPLED INTEGRATION (Acrobat 581K) #1393, 10 pgs.
Alan R. Barnett -- Analex Corporation
Omar M. Ibrahim -- Analex Corporation
Ayman A. Abdallah -- Analex Corporation
Timothy L. Sullivan -- National Aeronautics and Space Administration

ABSTRACT: By utilizing MSC/NASTRAN DMAP in an existing NASA Lewis Research Center coupled loads methodology, solving modal equations of motion with initial conditions is possible using either coupled (Newmark-Beta) or uncoupled (exact mode superposition) integration available within module TRD1. Both the coupled and newly developed exact mode superposition methods have been used to perform transient analyses of various space systerns. However, experience has shown that in most cases, significant time savings are realized when the equations of motion are integrated using the uncoupled solver instead of the coupled solver. Through the results of a real-world engineering analysis, advantages of using the exact mode superposition methodology are illustrated.

SPACE STATION SOLAR ARRAY POINTING SYSTEM CONTROL/STRUCTURE INTERACTION STUDY USING CO-ST-IN FOR MODAL REDUCTION (Acrobat 976K) #6893, 22 pgs.
Tarun Ghosh -- Rockwell International Corporation
Benigno Muniz Jr. -- Rockwell International Corporation
Joseph Cheng -- Rockwell International Corporation
Marsha Nall -- NASA Lewis Research Center

ABSTRACT: The control/structure interaction problem of orienting the Space Station Freedom (SSF) PhotoVoltaic arrays is solved to achieve desired system pointing performance using the Beta Gimbal Drive Mechanism. The vibration modes of the on-orbit SSF Stage Configuration 17 are calculated using MSC/NASTRAN finite element models which presently comprise a total of 250,000 degrees of freedom. In-house Direct Matrix Abstraction Programs and post-processors are developed for more efficient and accurate Craig-Bampton modal reduction with geometric stiffening and either modal displacement or modal acceleration data recovery. Structural Dynamic Research Corporation's CO-ST-IN post-processor is used to rank the vibration modes for control system analysis. The problem of solving an actual case of ranking modes using CO ST-IN for large-scale SSF application is illustrated. Examples of calculated control system response including the effects of reduced flexible mode dynamics are shown.

SSF FLEXIBLE MULTI-BODY CONTROL/STRUCTURE INTERACTION SIMULATION (Acrobat 711K) #1593, 19 pgs.
Timothy T. Cao -- NASA JSC/ES
Huang-Tsang Chang -- DYNACS Engineering Co.
Tuyen Hua -- NASA JSC/EG2

ABSTRACT:

A SUPEREFFICIENT, MSC/NASTRAN-INTERFACED COMPUTER CODE SYSTEM FOR DYNAMIC RESPONSE ANALYSIS OF NONPROPORTIONALLY DAMPED ELASTIC SYSTEMS (Acrobat 748K) #1493, 16 pgs.
Rong C. Shieh -- MU, Inc.

ABSTRACT: With the emphasis on frequency response analysis case, development of the title computer code capability and application of the latter in evaluation of the computational efficiency of the MSC/NASTRAN code itself in the dynamic structural response analysis of nonproportionally . damped elastic systems are made in this study. In this system, MSC/NASTRAN is used mainly for physical or modal structural (mass, damping, and stiffness) matrix assembling. The newly developed CMODEAN (Complex MOde/DEcoupling ANalysis) module uses the structural matrices as input for complex normal modes (state eigenmodes) calculation and equations of motion decoupling. Computational efficiency of CMODSTAN over MSC/NASTRAN for frequency response analysis of nonproportionally damped systems is demonstrated by an example problem with 225 dynamic degrees of freedom.

Dynamics Analysis

ACCURATE ENFORCED MOTION ANALYSIS USING MSC/NASTRAN SUPERELEMENTS
(Acrobat 666K) #2594
Christopher C. Flanigan -- SDRC Engineering Services Division, Inc.

ABSTRACT: The standard approach for performing an enforced motion analysis in MSC/NASTRAN uses very large masses and forces to obtain the desired motion at selected locations. This approach can lead to inaccurate results if the large masses are too large or too small.

An alternate approach for enforced motion analysis is presented in this paper. The alternate method uses the Craig-Bampton superelement capability in MSC/NASTRAN to form the required matrices for a direct solution of the equations of enforced motion. The need for large masses is eliminated, resulting in improved accuracy. In addition, the enforced motion analysis is performed directly, eliminating the need for Lagrange multipliers.

A rigid format alter for performing the new enforced motion analysis method is included in the paper. An example problem is presented to demonstrate the new method and to illustrate some of the pitfalls of enforced motion analysis.

ACOUSTIC SENSITIVITY ANALYSIS USING BOUNDARY ELEMENTS AND STRUCTURAL DYNAMIC RESPONSE (Acrobat 737K) #0794, 14 pgs. Nickolas Vlahopoulos -- Automated Analysis Corporation S.T. Raveendra -- Automated Analysis Corporation Chris Mollo -- Automated Analysis Corporation

ABSTRACT:

In this work two BE formulations, the Direct and Indirect, have been coupled to MSC/NASTRAN design sensitivity results to compute the acoustic sensitivity with respect to structural design variables. The theoretical background of the coupling algorithm is presented along with some examples of noise prediction in interior and exterior noise radiation.


AEROELASTIC MODELLING OF AN AIRPLANE WITH STAND-BY ACTUATOR USING MSC/NASTRAN FOR FLUTTER ANALYSIS (Acrobat 481K) #3394, 16 pgs.
Yan Mursal -- Pt.IPTN/Indonesia Aircraft Industry Ltd.
Moh. Risdaya Fadil -- Pt.IPTN/Indonesia Aircraft Industry Ltd.: ABSTRACT: The aircraft control surfaces that were considered in this paper are driven by a pair of hydraulically powered servo actuators. One actuator is normally in an active mode and the other is normally in a stand-by mode. This paper describes an aeroelastic modeling technique where a control System has two hydraulic failures, the active mode actuator is failed (e.g. a structural disconnect) and no hydraulic power comes to the stand-by mode actuator. In this situation the stand-by mode acts as a hydraulic damper.
In the failure condition, the stand-by actuator must provide sufficient damping in order the airplane still maintain flutter free condition. To perform the aeroelastic analysis of the System, the generalized mass, stiffness and damping of the plant (airplane) equation must be modified. These tasks were done using the combination of EPOINT, TF MSC/NASTRAN bulk data entry and DMAP. The EPOINT entry was used to add one generalized coordinate. In this case it is due to the moment of the actuator introduced to the airplane. The Nastran TF bulk data was used to introduce the diagonal terms of the MHH, BHH and KHH matrices. A small DMAP routine was created to add off-diagonal terms of these matrices and to perform the analysis automatically. The calculation was done using SOL 145. Some results are presented as an example and also compared with another method.
ANALYSIS AND MODAL SURVEY TEST INTELSAT VIIA DEPLOYED SOLAR ARRAY (Acrobat 469K) #2794, 12 pgs. K. C. Jiang -- Space Systems/Loral R. Gahart -- Space Systems/Loral
DYNAMIC ANALYSIS BY THE FOURIER TRANSFORM METHOD WITH MSC/NASTRAN (Acrobat 1.07MB) #1095, 23 pgs. Dean Bellinger--The MacNeal-Schwendler Corporation
DYNAMIC DESIGN ANALYSIS METHOD (DDAM) USING MSC/NASTRAN (Acrobat 314K) #3194, 10 pgs. Pam Barber -- Newport News Shipbuilding Kevin Arden -- Newport News Shipbuilding
AN EFFICIENT PROCEDURE FOR DATA RECOVERY OF A CRAIG-BAMPTON COMPONENT (Acrobat 506K) #2694, 15 pgs. Edward T. Tong -- Rockwell International Craig C.J. Chang -- Rockwell International
MODEL REDUCTION AND MODEL CORRELATION USING MSC/NASTRAN (948K) #0895, 16 pgs. Y T. Chung--McDonnell Douglas Aerospace Company-West
SHAKE TEST SIMULATION USING MSC/NASTRAN (Acrobat 744K) #3294, 21 pgs.
Randal H. Visintainer -- Ford Motor Company
Farhang Aslani -- Automated Analysis Corporation: ABSTRACT: Advances in Computer-Aided Testing technology have led to the Simulation of Service Operation and test track loads in the laboratory. The controlled environment of the lab creates an ideal Situation for attempts to simulate the lab test. Furthermore, the concept of up-front engineering using analytical prototype has pushed the demands on the CAE analysts to develop methodology to simulate operating conditions, durability events, and laboratory tests. To address this need, the frequency response solution (SOL 111) of MSC/NASTRAN is used to simulate the vehicle shake test of a heavy truck. The displacement-controlled lab test was performed between the frequency range of 20 to 50 Hertz (Hz). The MSC/NASTRAN simulation of the test and the correlation between the test and analysis results revealed several important points that should be considered in a computer simulation using the analytical prototype.
SIMULATION OF PROVING GROUND EVENTS FOR HEAVY TRUCK CABS USING ADAMS, MSC/NASTRAN, and P/FATIGUE (Acrobat 862K) #0594, 19 pgs.
Farhang Aslani -- Automated Analysis Corporation
Manicka Yatheendar -- Automated Analysis Corporation
Randal H. Visintainer -- Ford Motor Company
David S. Rohweder -- Ford Motor Company
Juan Lopez de Alda -- Mechanical Dynamics Inc.

ABSTRACT: The concept of up-front engineering using analytical prototype has pushed the demands on the CAE analysts to develop methodologies which simulate operating conditions, proving ground events, and laboratory tests well ahead of the availability of structural prototypes of the vehicle. One purpose of such analysis is to provide fatigue life prediction at an early stage of the design to permit the incorporation of design modifications prior to initial tooling release. The stress history resulting from the operation of the vehicle on the proving ground events can be simulated by enforcement of the profile of proving ground events using transient analysis in MSC/NASTRAN However, some of the proving ground events for heavy truck cabs include tire patch displacement of 12 inches that can not be simulated in MSC/NASTRAN directly. A methodology has been developed for use of the ADAMS vehicle model which provides accelerations at the cab mounts under those events. The acceleration response from the ADAMS model was used to perform transient analysis in MSC/NASTRAN to predict the time history of stresses in the cab. The time history of the stresses are input to the P/FATIGUE program to predict fatigue life of the structure under specific proving round events.

A STUDY ON THE ANALYSIS AND IMPROVEMENT OF THE ACOUSTIC CHARACTERISTICS OF THE MUFFLER WITH COMPLEX GEOMETRY (Acrobat 466K) #0694, 10 pgs.
Jin-Yong Mo -- SAMSUNG ELECTRONICS Co
Man-Sun Huh -- SAMSUNG ELECTRONICS Co
Jung-Rae Kim -- SAMSUNG ELECTRONICS Co
Heui-Jong Kang -- SAMSUNG ELECTRONICS Co
Sang-Kyoung Oh -- SAMSUNG ELECTRONICS Co

ABSTRACT: An acoustic transmission loss analysis method for mufflers with complex geometry is developed using MSC/NASTRAN on the basis of acoustic-structural analogy and two-microphone method. In this study, mufflers with simple and complex shapes are analyzed using this method and compared with theoretical and experimental results for verification.
Applying this method to design of suction muffler of reciprocating compressor, we could obtain 4dB(A) total noise reduction, especially more than 10dB(A) noise reduction at 500Hz.
VIBROACOUSTICS RANDOM RESPONSE ANALYSIS METHODOLOGY (Acrobat 566K) #0995, 11 pgs.
Gregory J. Michels--Eastman Kodak Company

ABSTRACT: The theory, application, and assumptions of a dynamic modal analysis based technique are presented to familiarize users with a method to use MSC/NASTRAN to determine the random response of a structure subjected to acoustic loads. Emphasis is placed on computing the mechanical response of a structure due to applied acoustic loads with worst case spatial correlation. MSC/NASTRAN solutions 101, 103 and 111 with the random response processor are used in the analysis method.

Electromagnetics

EDDY CURRENT SIMULATIONS FOR THE SSCL LOW ENERGY BOOSTER CAVITY (Acrobat 420K) #1693, 11 pgs.
Y Goren -- Superconducting Super Collider Laboratory
L. Walling -- Superconducting Super Collider Laboratory

ABSTRACT:

INDUCTION FURNACES: INTEGRATED MSC/EMAS, MSC/XL, AND MSC/NASTRAN ANALYSIS (Acrobat 873K) #2093, 25 pgs.
Vern D. Overbye -- STM Consulting, Inc.
Glenn H. Stalker -- STM Consulting, Inc.
Scott M. Schaefer -- STM Consulting, Inc.
Roy H. VanderHeiden -- STM Consulting, Inc.
S. Rajendran -- Mobil Solar Energy Corporation

ABSTRACT:

MAGNETIC SENSOR DEVELOPMENT USING FINITE ELEMENT ANALYSIS (Acrobat 990K) #1893, 18 pgs.
T.J. Wagener -- Honeywell Systems and Research Center
James R. Campbell, Jr. -- Honeywell Systems and Research Center
James E. Lenz -- Honeywell Systems and Research Center

ABSTRACT:

MSC/EMAS NONLINEAR TRANSIENT ANALYSES OF MULTITURN COILS WITH ATTACHED CIRCUITS (Acrobat 622K) #2293, 14 pgs.
John R. Brauer -- The MacNeal-Schwendler Corporation
Charles R. Figer, Jr. -- The MacNeal-Schwendler Corporation

ABSTRACT:

3D NONLINEAR MAGNETIZATION STUDIES OF THIN AMORPHOUS RIBBONS (Acrobat 558K) #1993, 10 pgs.
Richard L. Copeland -- Sensormatic Electronics Corporation
Markus B. Kopp -- Sensormatic Electronics Corporation

ABSTRACT:

USING FINITE ELEMENT SOFTWARE TO PREDICT EMC PERFORMANCE FROM ELECTRICALLY SMALL SOURCES (Acrobat 555K) #1793, 9 pgs.
Mark L. Markel -- General Motors Corporation

ABSTRACT:

USING MSC/EMAS IN STIMULATING A PARALLEL MICROSTRIP TRANSMISSION LINE (Acrobat 298K) #2193, 9 pgs.
Markus B. Kopp -- Sensormatic Electronics Corp.
Vichate Ungvichian, Ph.D. -- Florida Atlantic University
Richard L. Copeland, Ph.D. -- Sensormatic Electronics Corp.

ABSTRACT:

MSC/EMAS produced results that are accurate to within 4 percent of the closed form solution. It also clearly demonstrated that the magnitude of crosstalk, as a function of substrate height, asymptotically approaches a final value.

Electronics

STRUCTURAL ANALYSIS OF KA-BAND GIMBALED ANTENNAS FOR A COMMUNICATIONS SATELLITE SYSTEM (Acrobat 192K) 1996, 15 pgs. Hong Su--COM DEV Ltd.

ABSTRACT

3D MSC/EMAS SIMULATION OF A THREE PHASE POWER TRANSFORMER BY MEANS OF ANISOTROPIC MATERIAL PROPERTIES (Acrobat 544K) 1996, 11 pgs. Dr. E. Schmidt--University of Technology, Vienna S. Ojak--University of Technology, Vienna ABSTRACT: This paper deals with the MSC/EMAS simulation of a three phase power transformer using a 3D finite element model. The most important part of the presented simulation is the modelling of the multiturn windings and the iron core by means of anisotropic material properties. Characteristic calculation results with the derived transformer model will show that the modelling technique is practicable for many low frequency applications.

Elements

ANALYSIS OF SHELL STRUCTURES USING MSC/NASTRAN'S SHELL ELEMENTS WITH SURFACE NORMALS (Acrobat 643K) #2695, 18 pgs.
C.C.Hoff--MacNeal-Schwendler Corporation
R.L.Harder--MacNeal-Schwendler Corporation
G.Campbell--Ford Motor Company
R.H.MacNeal--MacNeal-Schwendler Corporation
C.T.Wilson--MacNeal-Schwendler Corporation

ABSTRACT: MSC/NASTRAN's lower order shell elements TRIA3, QUAD4, TRIAR, and QUADR are some of the most frequently used shell elements in the finite element market. The performance and quality of MSC's shell elements have been tested over a long period of time, but there is still potential for improvement. It has been reported that moderately thick shell elements with transverse shear flexibility are too soft in twist for cases where additional bending and membrane forces are active. In addition, spurious out-of-plane rotations have been reported. The behavior occurred only in very few practical problems and it did not appear in the MacNeal-Harder standard test problems. Unique surface normals at grid points are introduced in MSC/NASTRAN Version 68.2 to improve the behavior of the shell elements. The improvement of shells with normals is shown.

COMGEN-BEM: BOUNDARY ELEMENT MODEL GENERATION FOR COMPOSITE MATERIALS MICROMECHANICAL ANALYSIS (Acrobat 1.88MB) #2395, 20 pgs.
Robert K. Goldberg--NASA Lewis Research Center
Michele D. Comiskey--University of Akron

ABSTRACT: COMGEN-BEM (Composite Model Generation - Boundary Element Method) is a program developed in MSC/PATRAN's PATRAN Command Language (PCL) which generates boundary element models of continuous fiber reinforced laminated and woven composites at the micromechanical (constituent) scale. Through the use of menus and forms, the user enters a few simple parameters such as fiber volume fraction, fiber diameter, mesh density, material properties, fiber rotation information and load and boundary condition data. From the user defined parameters, a complete boundary element model is automatically generated. Once the model is generated, the user can invoke a provided translator to convert the model information into an appropriate boundary element analysis input format. This program demonstrates the ability of MSC/PATRAN and PCL to simplify the parametric generation of boundary element models in general, and composite micromechanical models in particular.

AN INTERFACE ELEMENT FOR GLOBAL/LOCAL AND SUBSTRUCTURING ANALYSIS (Acrobat 1.48MB) #2595, 20 pgs.
Jerrold M. Housner--NASA Langley Research Center
Mohammad A. Aminpour--Old Dominion University
Carlos G. Davila--National Research Council Associate
John E. Schiermeier--MacNeal-Schwendler Corporation
W. Jefferson Stroud-- NASA Langley Research Center
Jonathan B. Ransom--NASA Langley Research Center
Ronnie E. Gillian--NASA Langley Research Center

ABSTRACT: NASA and the MacNeal Schwendler Corporation have entered into a cooperative agreement to further the development of Interface Technology for finite element modeling. This new technology enables incompatibly meshed models to be accurately joined together even when their grid points do not coincide. Until recently, this technology was being developed solely by NASA. To improve technology transfer and to ensure relevancy of NASA developments in this area, NASA and MSC will work together to extend the capability in an experimental version of MSC/NASTRAN. This paper describes the Interface Technology, demonstrates its capabilities and value, and reviews the activity of the NASA/MSC joint venture.

USE OF MSC/NASTRAN GENERAL ELEMENTS IN COMPLEX STATIC PROBLEMS (Acrobat 855K) #2495, 19 pgs.
Mitchell L. Greenberg--Spar Space Systems

ABSTRACT: This paper shall explore uses of MSC/NASTRAN general (GENEL) elements. Basic stiffness matrix concepts as pertaining to GENEL formulation will be discussed, and techniques to reduce large linear static structures to a single GENEL connected at the boundary GRIDs shall be presented. The methods herein provide an alternative to and supplement the capabilities of SuperElements for manipulating and modelling sub-components.

Fatigue Analysis

ANALYTICAL FATIGUE LIFE ASSESSMENT OF VIBRATION INDUCED FATIGUE DAMAGE (Acrobat 786K) #1895, 17 pgs.
NWM Bishop--University College London (UCL)
LW Lack--nCode International
T Li--Ford Motor Company
SC Kerr--University College London (UCL): ABSTRACT: Vibration testing of components using accelerated test tracks or laboratory simulators is widely used in automotive design, as is fatigue testing for reliability. Furthermore, there are many common features between these two disciplines. However, problems often arise when engineers who are skilled in one field have to use techniques and concepts more generally used in the other. One example of such a situation concerns the use of frequency domain descriptions of structural response, which are commonplace in vibration testing for ruggedness, for computing the fatigue life or reliability of the same component. Many engineering applications, such as offshore engineering and wind turbine engineering, have already seen the benefits of using frequency domain fatigue tools for reliability assessment. The purpose of this paper is to assess the benefits of frequency domain fatigue analysis by comparison with a more conventional time series transient fatigue analysis. A typical automotive component has been analysed using MSC/NASTRAN and MSC/PATRAN FATIGUE in both the time domain (using a transient time history analysis) and in the frequency domain using spectral fatigue analysis techniques. Probability density functions and fatigue lives computed using the output from these two different approaches show good agreement.

FATIGUE ANALYSIS USING RANDOM VIBRATION (Acrobat 389K) #1795, 8 pgs.
H. L. Schwab--Ford Motor Company
J. Caifrey--F.E.Tools
J. Lin--Ford Motor Company

ABSTRACT

A LIFE PREDICTION ALGORITHM IMPLEMENTED IN P3 USING PCL (Acrobat 1.01MB) #1995, 11 pgs.
Matthew E. Melis--NASA Lewis Research Center
Joseph A. Ogonek--Analex Corporation

ABSTRACT: A life prediction methodology is implemented in P3 through a computer program, Probable Cause, written in Patran Command Language (PCL). The software uses finite element analysis data, and probabilistic material parameters to predict the component life and probability of survival for the analysis model. Probable Cause is imbedded in P3 and is accessed through a graphical user interface called from the main menu bar.

The theory in Probable Cause is briefly outlined in this paper and its use is demonstrated with a finite element analysis of a jet engine turbine disk. The usefulness of PCL in accomplishing a task of this nature is shown and the lessons learned in the development process are discussed.

A Life Prediction Algorithm Implemented in P3 Using PCL 1.

A SPOT-WELD FATIGUE ANALYSIS MODULE IN THE MSC/FATIGUE ENVIRONMENT (Acrobat 256K) 1996, 13 pgs. Peter Heyes--nCode International Limited Mikael Fermér--Volvo Car Corporation: ABSTRACT: A software system has been developed in the MSC/FATIGUE [1] environment which permits fatigue life predictions to be made for automotive spot-welds joining two steel sheets. The method uses bar element forces to calculate the "structural stresses" in each spot-weld nugget and the adjacent sheets using the methodology described by Rupp, Störzel and Grubisic [2]. The system described here extends this general method to support the use of dynamic stresses derived from road load data, using either a quasi-static or transient approach to stress history determination. The method is geometry independent and suitable for application to large models (because it does not require local mesh refinement). The system provides a convenient way for users of MSC/PATRAN [3], MSC/NASTRAN [4] and MSC/FATIGUE to predict the location and life of fatigue sensitive spot-welds.

A STEPWISE APPROACH FOR FATIGUE EVALUATION OF ENGINE ACCESSORIES PRIOR TO PROTOTYPING USING HYBRID MODELLING TECHNOLOGY (Acrobat 1.7MB) 1996, 12 pgs. L. Gielen--LMS International M. Brughmans--LMS International C. Petellat--MACK

VIBRATION FATIGUE ANALYSIS IN THE FINITE ELEMENT ENVIRONMENT (Acrobat 4.3 MB) #1398, 15 pgs.
Dr. Neil Bishop and Alan Caserio--MSC

ABSTRACT: Fatigue damage is traditionally determined from time signals of loading, usually in the form of stress or strain. However, there are many design scenarios when the loading, or fatigue damage process, cannot easily be defined using time signals. In these cases the design engineer usually has to use a test based approach to evaluate the fatigue life of his structure or component. Or, alternatively, a frequency based fatigue calculation can be utilized where the loading and response are categorised using Power Spectral Density (PSD) functions.

One very important design problem, which falls into this category, is that of acoustic fatigue. However, there are also many other situations where structures are subjected to a random form of loading such as wing flutter, landing gear runway profiles, engine vibrations and so on. All of these situations can be analysed using new fatigue life estimation techniques now incorporated in MSC/FATIGUE.

The theory of random vibration fatigue has seen a number of important developments over the last fifteen years. The authors have been personally involved in developing new fatigue analysis theories and structural analysis techniques in the frequency domain. More recently this work has focused on the link with Finite Element Analysis (FEA) because of the powerful design opportunities which this creates. The work has found many important practical applications. This paper will provide a state of the art perspective of random vibration fatigue technology. A number of design applications will be presented.

General Stress Analysis

APPLICATIONS OF FINITE ELEMENT ANALYSIS FOR AN IMPROVED MUSICAL INSTRUMENT DESIGN (Acrobat 896K) 1996, 20 pgs. Mark Carlson--Fender Musical Instruments Corporation

ABSTRACT

bending and twisting of the neck due to string forces
bending and twisting of the neck due to moisture content expansion forces
the cylindrical orthotropic nature of wood
individual musician's preferences (neck adjustment capability)
elimination of less resonant "dead spots" which occur for certain notes on the neck

Several analysis types will be utilized for different steps of the design phase as follows:

linear static analysis for stability against string and moisture content loads
nonlinear slideline contact analysis for developing the adjustment capability
unstressed and prestressed modal analysis for tuning out "dead spots"

APPLYING VIRTUAL REALITY TECHNOLOGIES TO THE INTERACTIVE STRESS ANALYSIS OF A TRACTOR LIFT ARM (Acrobat 455K) #0198 , 15 pgs.
Michael J. Ryken, and Dr. Judy M. Vance-- Iowa State University

ABSTRACT: The objective of this research is to examine the challenges of applying virtual reality techniques to the interactive stress analysis of a tractor lift arm. NURBS-based free form deformation, finite element analysis, sensitivity analysis, collision detection, and virtual reality are combined to create an interactive environment for designers to view and modify part shape, evaluate the resulting stresses, and check for interference of the new part shape and surrounding parts in real-time. These methods are implemented using a surround screen virtual environment where the part of interest and associated geometry surrounding that part are displayed together using stereo projection to provide a three-dimensional view of the assembly.

COMPARISON OF MSC/NASTRAN ANALYSIS RESULTS TO SOME WELL KNOWN CLOSED FORM SOLUTIONS TO GUIDE MODELING OF VEHICLE STRUCTURES (Acrobat 1.3MB) 1996, 14 pgs.
Bijan K. Shahidi--Ford Motor Company
John V. Fazio--Ford Motor Company

ABSTRACT

There are several options available in MSC/NASTRAN when one desires to create a finite element model of a vehicle structure. The question that remains unanswered is, what is the best way to model a vehicle in a real world environment economically, and believe in the results without creating the actual part for testing. In order to gain some insight and answer this question, one often looks into the well-known classical mechanics problems in literature where there is either a closed form solution or a repeatable lab experiment conducted in a controlled envionment, to compare with modeling techniques.

In this paper, several classical problems are sought from literature, which are modeled using MSC/NASTRAN, and the results are compared to one another. The problems range from linear static analysis of slender beams to free vibration and nonlinear static analysis. The conclusions are drawn from the comparison of several modeling methods to the closed form solutions available to the authors. It is found that one must take great caution when modeling a vehicle structure on choice of element types, their size and range validity. Discussions on the accuracy of results in deflection analysis vs. stress or vibration analysis are made by using different modeling methods and rationalizing the comparison of the results to the analytical solutions.

COMPARISON OF THE MSC/NASTRAN AND HOLOGRAPHIC INTERFEROMETRY DATA ON A LOCAL STRAIN/STRESS EVALUATION IN THE ELASTO-PLASTIC RANGE (Acrobat 992K) 1996, 21 pgs. A.S. Dzuba--Moscow Institute of Physics and Technology V.D. Grigoriev--Moscow Institute of Physics and Technology V.S. Pisarev--Moscow Institute of Physics and Technology

ABSTRACT

The elastic stress concentration problem in a thin plane specimen under tension and thin-walled curved circular cylindrical shell subjected to torsion are considered carefully through the use of the Version 68.1. The accuracy of numerical results in both cases is established by comparing them with the corresponding experimental data obtained by means of holographic interferometric measurements. The calculation of maximum stress values is carried out by using QUAD4 Corner Output. An excellent agreement between numerical and experimental results have been revealed.

An evolution of local elasto-plastic strains in a thin plane strip with a circular open hole under static tension is studied. The data of holographic interferometric measurements are used again in order to estimate the accuracy of numerical solution for different levels of applied external load. An influence of the circumferential strain gradient on results of a maximum elasto-plastic strain calculation is dicussed in detail.

MSC'S SOLVERS PREDICT THE BEST ATTACHMENT OF THE SUNBEAM TIGER FIBERGLASS FRONT-END (Acrobat 160K) 1996, 5 pgs. Gert Lundgren--LAPCAD Engineering

ABSTRACT

The proper choice of the occlusion pattern, hereafter considered the way prosthetic and dental cusps fit together, is fundamental for the homogeneous distribution of mastication loading around implants that totally support the prosthesis.

Through the Finite Element Method, the stress distribution around the prosthesis supporting implants has been studied. Two kinds of occlusion patterns have been considered: canine guide and balanced occlusion. The three-dimensional finite element model of the lower jaw with a prosthesis supported by six osseointegrated implants was developed and analyzed regarding both loading (occlusion) conditions. MSC/XL was used for pre and post-processing and MSC/NASTRAN for the analysis. Considering just the biomechanical aspects, it was observed that:

The balanced occlusion shows stress distributions around the implants more homogeneous than the canine guide;
The regions around distal (border) implants on both sides of the mandible were the most stressed;
The working side shows higher stress concentration in both simulations. Many interesting challenges were identified allowing to expect for increasing interest in this interdisciplinary field of research.

Interfaces to MSC/NASTRAN

AN ADVANCED POST PROCESSING METHODOLOGY FOR VIEWING MSC/NASTRAN GENERATED ANALYSES RESULTS (Acrobat 529K) #2194, 7 pgs. Michael McMeekin -- Swales and Associates Paul Kirchman -- Swales and Associates
CREATING A FINITE ELEMENT MODEL WITH THE MSC/ARIES APPLICATION MODULES (Acrobat 993K) #2394, 17 pgs.
Marianne L. Kronenberg -- The MacNeal-Schwendler Corporation: ABSTRACT: Software generated solid models provide complete and unambiguous visual and mathematical definition of design objects. The MSC/ARIES Solids software application module affords an easy to use, highly intuitive way of creating solid models to capture the design intent of engineers and analysts. The objectives of this presentation are to:

USING VERSION 67.5 OUTPUT2 NEUTRAL FORMAT OPTION FOR FILE TRANSFER ACROSS DISSIMILAR MACHINES (Acrobat 297K) #2494, 8 pgs.
John Brown -- Northrop Corporation
Grant Parker -- Northrop Corporation
Ted Rose -- The MacNeal-Schwendler Corporation

ABSTRACT: A new option in Version 67.5 provides the ability to write OUTPUT2 files in a machine-independent format. Northrop's Aircraft Division F/A-18 E/F Program has migrated a large portion of its engineering computer use from a large mainframe to a multi-node client/server networked workstation environment. Finite element modeling and analysis software, both proprietary and commercial, have been migrated to the workstation - including MSC/NASTRAN.
Special features in Northrop's mainframe based proprietary pre and post processing code (NCASA) has required its continued use. This mainframe program requires OUTPUT2 data from MSC/NASTRAN. Prior to the introduction of workstations, both NCASA and MSC/NASTRAN were resident on the mainframe, and transfer of files between the programs was not a problem.
VARIATION ANALYSIS BY MONTE CARLO RANDOMIZATION OF LOAD VARIATION SENSITIVITIES (Acrobat 1.38MB) #2294, 21 pgs.
Mark J. Stone -- Eastman Kodak Company ABSTRACT: Most analysis considers only the nominal loads acting on a structure, but there may be significant impact due to the variation or error in the loads as well. When there are multiple load sources, the effect from the combination of these load variations is difficult, if not impossible, to predict. This paper describes the use of a Monte Carlo randomization method applied to the displacement results generated from MSC/NASTRAN analyses using sensitivity loads. A Monte Carlo process is used to efficiently obtain a statistical distribution of possible results from the random combination of load variations. Using the method presented minimizes the number of analyses which must be run in order to obtain a population of results from which accurate conclusions can be drawn. The model used represents the High Resolution Mirror Assembly (HRMA) for NASA's Advanced X-ray Astrophysics Facility-Imaging (AXAF-I). The variation analysis discussed considers the impact from support induced load variations during alignment and assembly of the AXAF-I mirrors to the mounting structure.

MSC/DYTRAN

CRASH SIMULATION OF A 1/5-SCALE MODEL COMPOSITE FUSELAGE CONCEPT (Acrobat 1.2MB) #0399, 14 pgs. Karen E. Jackson and Edwin L. Fasanella--U.S. Army Research Laboratory, Vehicle Technology Center Sotiris Kellas--MRJ Technology Solutions

ABSTRACT: This paper describes the MSC/DYTRAN crash simulation of a 1/5-scale model composite fuselage concept, which was developed to satisfy structural and flight loads requirements and to satisfy design goals for improved crashworthiness. The fuselage consists of a relatively rigid upper section which forms the passenger cabin, a stiff structural floor, and an energy absorbing subfloor which is designed to limit impact forces during a crash event. The impact design requirement for the scale model fuselage is to achieve and maintain a 125-g floor-level acceleration for a 31 ft/s vertical impact onto a rigid surface. This impact requirement corresponds to a 25-g floor-level acceleration for a geometrically-similar full-scale fuselage section. To demonstrate compliance with the impact design requirement, the scale model fuselage section was impacted at 31 ft/s vertical velocity onto a rigid surface. The experimental data demonstrate that the fuselage section with a foam-filled subfloor configuration satisfied the impact design requirement. In addition, a second drop test was performed with a 15°-roll impact attitude, which demonstrated that the fuselage concept maintained good energy absorption behavior for an off-axis impact condition. As an aid in the evaluation process, a detailed three-dimensional finite element model of the 1/5-scale model fuselage section was developed using MSC/DYTRAN. Good correlation was obtained between the experimental data and the MSC/DYTRAN analytical results for both impact conditions.

HTML- AND VRML-BASED RESULTS REPORTING FOR MSC/DYTRAN AND MSC/SuperForge
(Acrobat 553K ) #4699, 10 pgs.
Darin Mckinnis and Arjaan Buijk--The MacNeal-Schwendler Corporation

ABSTRACT:MSC/DYTRAN is a general purpose 3D, transient non-linear explicit finite-element and finite-volume solver. Result inspection for MSC/DYTRAN models is difficult because of the large variety of problems and the fact that models may include large deformations, failed elements, fluids, fluid-structure interaction, and fluid free-surfaces. The amount of data generated by an MSC/DYTRAN calculation can be over whelming, especially for the novice user.
Traditional results inspection methods use ASCII based output files for summaries and error messages, and the most common visualization method is to use powerful post-processing software tools such as MSC/PATRAN to view the MSC/DYTRAN results stored in binary results files.

A new method of results inspection will be introduced. MSC/DYTRAN will automatically generate an HTML and VRML based report, which provides access to the results in a structured, fast and easy way. The results are web-based, and can thus be shared directly with others.

SMALL DEBRIS IMPACT SIMULATION USING MSC/DYTRAN(Acrobat 3.2 MB) #4599, 15 pgs.
Franco Olmi and Kennedy Diniz do Nascimento--EMBRAER

ABSTRACT:The problem of rotor blade fragment impact against an airplane fuselage (representing the "Small Debris" effect, due to rotor burst) has been investigated. The simulations were performed using the MSC/DYTRAN software, taking into account some different approaches, such the influence of the finite elements modeling (comparison between solid and shell elements) as well as the material behavior (involving characteristics like constitutive law, strain rate effects and failure modes). Finally, to corroborate the analysis, the numerical results were compared with experimental data.

MSC/DYTRAN & MSC/FATIGUE

AIRFRAME WATER IMPACT ANALYSIS USING A COMBINED MSC/DYTRAN DRI/KRASH APPROACH, (Acrobat 986KB) #3697, 13pgs
Gil Wittlin--Dynamic Response, Inc.
Michael Smith and Ashish Sareen, Ph.D.--Bell Helicopter Textron, Inc.
Marv Richards--Simula Government Products, Inc.

ABSTRACT: This paper describes a Naval Air Warfare Center (NAWC) sponsored Small Business Innovation Research (SBIR) Phase I Program to achieve long-range U.S. Navy water impact design objectives. In this program, a complementary approach utilizing both a nonlinear finite-element analysis program (MSC/DYTRAN) and a hybrid impact analysis code (DRI/ KRASH) is used to demonstrate the potential for airframe water impact analysis. Several water impact conditions were analyzed comprising various combinations of forward velocity and sink speed using MSC/DYTRAN and DRI/KRASH. Sampling of results along with test data are provided with regard to fuselage underside pressure contours, floor accelerations, airframe-water interactive forces, response comparisons and trends. No similar results have previously been presented.

AN EVALUATION OF SERVICE LIFE ANALYSIS OF METALLIC AIRFRAME STRUCTURE WITH MSC/FATIGUE, (Acrobat 999KB) #3397, color, 15pgs
Mark T. Doerfler--Lockheed Martin Tactical Aircraft Systems

ABSTRACT

IMPLEMENTATION OF A FLUID-STRUCTURE INTERACTION FORMULATION USING MSC/NASTRAN, (Acrobat 287KB) #3597, 15pgs
S. S. Lee, M. C. Kim, and D. R. Williamson--The Aerospace Corporation

ABSTRACT

INTEGRATING ADAMS AND MSC/NASTRAN IN THE DESIGN CYCLE, (Acrobat 569KB) #3497, 14 pgs.
Dave Riesland--Mechanical Dynamics, Inc.

ABSTRACT: In order to bring better products to the market faster and at less cost, aerospace companies around the world are embracing the concept of concurrent engineering at a system level. ADAMS, the world leader in Mechanical System Simulation (MSS), ties together diverse component design and analysis technologies such as Computer Aided Design (CAD) and Finite Element Analysis (FEA) in a single system virtual prototype, providing a more complete understanding of product performance. In short, MSS provides the critical enabling technology for meeting true concurrent engineering goals.

SOLDER JOINT RELIABILITY IN PATRIOT MISSLE ELECTRONIC COMPONENTS USING MSC/FATIGUE
(Acrobat 228 K) # 4799, 10 pgs.
Martin E. Bowitz--Boeing North American, Inc.
Alan K. Caserio--The MacNeal-Scwendler Corporation

ABSTRACT:The reliability, or fatigue life, of solder joints is investigated in the Patriot Advanced Capability (PAC-3) missile for various electronic components using MSC/FATIGUE. Frequency response and random vibration analysis is performed using MSC/NASTRAN to extract transfer functions due to a 1G acceleration, and RMS stress levels. The suspect joints are modeled using 8 noded brick elements. Acceleration input load PSDs are defined based on measured vibration test and flight worthiness levels. Stress response PSDs are extracted to determine fatigue lives based on S-N methods. The calculated fatigue lives give confidence that the troublesome solder joints will not only endure the various qualification test, but that there will be enough remaining life to survive actual flight.

MSC/NASTRAN Applications

ANALYSIS AND TEST OF GUN BLAST RESISTANT COMPOSITE STRUCTURE(Acrobat 1.0MB) #2799, 11 pgs. Dennis K. McCarthy--The Boeing Company

ABSTRACT:The lower skins on the Extended Forward Avionics Bay (EFAB) on the AH-64D Apache are exposed to muzzle blast effects from a belly mounted 30 mm chain gun. These composite skins must be sufficiently strong to withstand blast pressure at a minimum weight. Analytical methods presented predict behavior of structure subject to gun muzzle blast. This resulted in a weight-optimized, blast-resistant EFAB design which was fabricated and attached to an aircraft. The chain gun was fired near these skins during hover and forward flight without structural damage. Strain data collected during gun fire verified the analytical method.

AN EFFICIENT AND EXACT SOLUTION FOR RANDOM VIBRATION ANALYSIS USING MSC/NASTRAN PART II: GENERAL RANDOM SPECTRUM(Acrobat 325 K) #3299, 17 pgs
E. de la Fuente and J.San Millán--Instituto Nacional de Tecnica Aeroespacial

ABSTRACT: A new method for performing RANDOM vibration analysis within MSC/NASTRAN is presented in this paper. The method is a direct application of a well known result of Linear Systems Theory, and allows computation of RMS values of any number of structural outputs: displacements, stresses, element forces, accelarations, etc. These results can be postprocessed as if they were originated in a conventional static analysis (in colour plots for instance). The method is implemented within MSC/NASTRAN by means of a DMAP Alter, that is carefully described in the paper. The results of this DMAP are compared with those given by standard RANDOM solution of MSC/NASTRAN, in terms of accuracy, CPU time, and calculation capability, showing clear advantages of the presented method. Finally, extensions of the method are outlined.

CAD/FEA INTEGRATION WITH STEP AP209 TECHNOLOGY AND IMPLEMENTATION, (Acrobat 283KB) #1297, 13 pgs
Keith A. Hunten, P.E.--Lockheed Martin Tactical Aircraft Systems

ABSTRACT: The requirements to share geometric shape and analysis information in a large-scale system, especially composite structures, are essential. An emerging standard, the ISO10300 STEP AP209, has been developed to address the data exchange to the design/analysis/manufacturing process. This paper describes the scope, progress and implementation of this effective standards-based solution.

COMPONENT MODE SYNTHESIS OF STRUCTURES WITH GEOMETRIC STIFFENING IN MSC/NASTRAN (Acrobat 130K) #3199, 26 pgs.
Tarun Ghosh--Boeing North American, Inc.

ABSTRACT: Implementation of modal synthesis in MSC/NASTRAN is usually done using structural solution sequence based Direct Matrix Abstraction Programs, DMAPs. However, modal synthesis in MSC/NASTRAN without using structural solution based DMAPs is possible. But either method is tailored towards supporting components that have no non-linearity. Certain components, such as the solar arrays of the space station, exhibit non-linear behavior in the form of geometric stiffening. For structures with such components, the standard method of modal synthesis does not work. Special DMAPs need to be developed for these components. Realizing that the only difference between components with no geometric stiffening and those with geometric stiffening is in the method of obtaining the stiffness matrix, a simple solution is provided in this paper. The solution is to use the procedure for modal synthesis for components with no geometric stiffening by replacing the stiffness matrix with the one obtained from geometric stiffening. This approach, along with the recommended check runs, has been shown to work successfully in this paper. The method is also shown to be extremely efficient.

CREATION & AUTOMATIC ATTACHMENT OF REDUCED COMPONENT MODELS FOR DYNAMIC ANALYSIS, (Acrobat 64KB) #1597, 17 pgs.
Ted Rose--The MacNeal-Schwendler Corporation

ABSTRACT

DYNAMIC SIMULATION OF A LARGE DEPLOYABLE SPACE STRUCTURE WITH PINNED JOINTS
(Acrobat 65 K) #3499, 8 pgs.
Wen Rong D.L.Wu--Beijing Institute of Astronautical Systems Engineering

ABSTRACT: Plays of joints strongly influence the dynamics of the large deployable space structures. In this paper, dynamic simulation of space structures with pinned joints is discussed. The study can be simply divided into two parts: the flexible effect of structure is simulated by MSC/NASTRAN, and the global motion of rigid body by DADS. The details of how to select the deformation modes in MSC/NASTRAN and how to deal with the digital problems in DADS will be given.
Keywords: Space Structures Gap Deployable Nonlinear MSC/NASTRAN DADS

EFFICIENT CALCULATION OF TRANSVERSE STRESSES IN COMPOSITE PLATES, (Acrobat 173KB) #1497, 17 pgs.
Raimund Rolfes--Institute of Structural Mechanics, DLR, Braunschweig, Germany
Ahmed K. Noor--Center for Advanced Computational Technology, University of Virginia, NASA Langley Research Center
Klaus Rohwer--Institute of Structural Mechanics, DLR, Braunschweig, Germany

ABSTRACT

AN EFFICIENT AND EXACT SOLUTION FOR RANDOM VIBRATION ANALYSIS USING MSC/NASTRAN PART I: WHITE NOISE SPECTRUM, (Acrobat 284KB) #3797, 19 pgs.
E. de la Fuente and J. San Millan--Instituto Nacional de Tecnica, Madrid, Spain

ABSTRACT

exact

IMPROVEMENTS TO THE DOUBLET-LATTICE METHOD IN MSC/NASTRAN(Acrobat 98 K) #3799, 16 pgs.
William P. Rodden--William P. Rodden, Ph.D., Inc.
Paul F. Taylor--Gulfstream Aerospace Corporation
Samuel C. McIntosh, Jr.--McIntosh Structural Dynamics, Inc.

ABSTRACT:The Doublet-Lattice Method (DLM) is in use worldwide for flutter and dynamic response analyses of aircraft at subsonic speeds. The DLM is an aerodynamic finite element method for modeling oscillating lifting surfaces that reduces to the Vortex-Lattice Method at zero reduced frequency. The number of finite elements (boxes) required for accurate results depends on aspect ratio and reduced frequency, among other parameters. At high reduced frequency, the chordwise dimension of the boxes must be small. A new version of the DLM relaxes limitations of the previous version to permit higher box aspect ratios so that the number of spanwise divisions (strips) can be reduced significantly, leading to a reduction in the total number of boxes. The new version also improves the accuracy of predicted aerodynamic damping. The new version has been integrated into MSC/NASTRAN as a no-charge option that is selected using a NASTRAN system cell.
The present paper summarizes the chordwise and spanwise convergence criteria and presents examples illustrating new modeling guidelines, a tip correction to reduce the sensitivity to the number of spanwise strips, and the reduced computing time possible with the new version.

INFLUENCE OF MODELING FOR ORTHOTROPIC MATERIALS PROPERTIES(Acrobat 390K) #3699, 7 pgs.
Ernst Dieter Sach, Georg Fleischmann and Wilfried Ulrich--DaimlerChrysler Aerospace AG

ABSTRACT: Shell type structures are usually modeled with plate elements (CQUAD, CTRIA). In case of thermal loads and orthotropic thermal expansion coefficients the analytical results do not represent the real behavior with sufficient accuracy. The reason is that changes in the thickness are not considered in the element stress/strain description which is correct for flat plates only. However, when a curvature is present, this effect leads to additional stresses and displacements.
As example a nozzle made of carbon fiber reinforced ceramics is used. For comparison an equivalent modeling with solid elements where the orthotropic properties can be fully represented, is applied. The differences in the results of the two models are shown.

AN INTEGRATED APPROACH TO RANDOM ANALYSIS USING MSC/PATRAN WITH MSC/NASTRAN
(Acrobat 520 K) #1099, 23 pgs.
Anthony Devenport--Northrop Grumman Corporation
Jim Leedom and Mohan Barbela--The MacNeal Schwendler Corporation

ABSTRACT:This paper describes an integrated and efficient approach to random analysis using MSC/PATRAN with MSC/NASTRAN. New enhancements available in MSC/PATRAN provide the analyst with an interactive pre- and post-processing environment for random analysis. These new features will be discussed and results presented demonstrating how the new capability was used on two different industry case studies. Performance improvements using the MSC/NASTRAN directaccess results database (xdb) over the standard output2 file will also be presented.

LANDING RESPONSE ANALYSIS OF AIRCRAFT WITH STORES USING MSC/NASTRAN, (Acrobat 57KB) #3997, 11 pgs.
Zeng Ning--South West United Machinery Corporation, Chengdu, P.R. China

ABSTRACT: In order to ensure safety flight of aircraft, it is very important to study the landing response analysis of aircraft with stores. Earlier aircraft was considered as a stiff body by reason of its lightweight and large structural stiffness. However, the structure of modern aircraft changes into more and more flexible with increasing of size and use of high strength materials. It would make for more accidents if the elastic effects were neglected for the aircraft. In this paper, the problem was solved successfully by means of generalized dynamic reduction and the large mass method of MSC/NASTRAN. The results in the paper show that the solution technique using MSC/NASTRAN is effective and feasible, which is especially suitable for the solution of the dynamic problem of large-scale structure subjected to base enforce motion.

LINK MESH MODEL OF AN ELEMENTARY PANEL BAY FOR LINEAR MSC/NASTRAN/PARAMETRIC ANALYSIS OF STIFFENED SHELLS, (Acrobat 57KB) #4097, 29 pgs.
Steven Basic, MS--Boeing Commercial Airplane Group

ABSTRACT

MICRO ELECTRONIC COMPONENTS VIBRATION FATIGUE DAMAGE EVALUATION(Acrobat 98K) #3399, 9 pgs.
T. E. Wong, F. W. Palmieri, B. A. Reed and H. M. Cohen--Raytheon Systems Company

ABSTRACT:In the current analysis tools, the outputs of random vibration analysis are limited to spectral densities and root-mean-square values of the strain components with no phase information, which is required to be able to correlate the strains and thus calculate von Mises strain resultant. In addition, due to the lack of phase information, it is impossible to use a macro-micro modeling technique, which is based on interpolation of the solution from an initial, relatively coarse, global model on the nodes at the appropriate parts of the boundary of the refined-meshed submodel, to determine the strains in the submodel. The objective of the present study is to develop a methodology to determine strains in electronic components (micro level) resulting from exposure of modules (macro level) to random vibration environments. Specifically, it addresses the problem associated with the analysis of almost microscopic elements attached to larger physical structures, e.g., ball grid array (BGA) solder balls attached to printed wiring board (PWB).
The proposed methodology includes two stages. The cross correlation of output displacement responses versus frequency for each of the degree of freedom of the connection points of the micro model to macro structure is first developed using a NASTRANTMfrequency response analysis of the macro model. In the second stage, a static analysis is conducted using NASTRANTM to generate the transfer functions of von Mises equivalent strains for each of the input source loading conditions. These transfer functions are then statistically correlated with the degree of correlation determined by the cross-spectral density in the first stage to calculate the auto-spectral density of the von Mises strains. In the methodology development process, several in-house developed Fortran computer programs, in conjunction with the outputs obtained from NASTRANTM static and frequency response analyses, are used to perform the required computations. An example of 600-pin BGA soldered onto the PWB is illustrated in the present study. Developing test modules, on which various sizes of the BGAs will be soldered, is currently under way to validate the proposed methodology.

MULTI-SPRING REPRESENTATION OF FASTENERS FOR MSC/NASTRAN MODELING, (Acrobat 322KB) #1397, 13 pgs.
Alexander Rutman, Ph. D and Joseph Bales-Kogan, M. Sc.--Boeing Commercial Airplane Group

ABSTRACT: The paper describes a particular modeling approach for 3-dimensional representation of fastener joints developed for MSC/NASTRAN. Different physical properties of plate-fastener systems are analyzed separately and interaction between them is established. Calculations of the system properties are shown, as well as the technique of their application in models. Description of a program automating generation of additional cards required by the method is included. The procedure is illustrated with an example showing both an application of the method and results of FEA based on its implementation.

ON CALCULATING THE RESPONSE OF AEROJET ENGINES WITH ROTOR IMBALANCE AND NON-LINEAR BEARINGS(Acrobat 228K) #2899, 14 pgs.
David Bella and Leo Dunne--CDH GmbH

ABSTRACT: Non-linear bearings are commonly used between the rotors and casing of aerojet engines. For rotor imbalance response calculations, these nonlinear components are often modeled as linear elements to avoid using the time consuming procedures required for nonlinear analysis. The standard procedure to determine the engine response requires several analyses in which the response of the previous run is used to determine the linear bearing properties for the new run. This iterative procedure is time consuming and neglects the engine response due to the
nonlinearities of the bearings. The methodology presented allows for efficient calculation of nonlinear response due to nonlinear bearings. The procedure is more stable and less resource intensive than a direct time-domain calculation and does not require manual iteration of bearing properties.
The analysis method takes advantage of the harmonic nature of rotor imbalance excitation and resulting engine response. The engine and bearing properties are transformed to a harmonic or frequency-domain representation. The system equations are then solved using an iterative procedure to determine the bearing properties and engine response. The iterative procedure calculates the response for one rotor revolution, the delity of the response is controlled by the number of harmonics used in the calculation. After the iterative calculation has converged, the system harmonic response is transformed to the time domain for standard data recovery. Suggestions for further improvements are also made.

OPTIMIZATION OF THE C/SiC THRUST CHAMBER FOR A 400N THRUSTER, (Acrobat 364KB) #3897, 10 pgs.
Georg Fleischmann and Ernst Dieter Sach--Daimler-Benz Aerospace AG

ABSTRACT

OPTIMIZED SPARSE SOLVER IN MSC/NASTRAN FOR COMPAQ ALPHA-BASED ARCHITECTURE
(Acrobat 65K) #1199, 15 pgs.
Susanne Balle,Chuck Newman, and Pari Rajaram--Compaq Computer Corporation

ABSTRACT: Numerical simulations of stress, vibration, and heat transfer for the analysis and optimization of structures and mechanical components are now mainstream engineering tools in the Aerospace and Automotive industries. As models become larger and more sophisticated, prediction accuracy increases, but computers need to work faster to keep turnaround time and throughput acceptable. In this paper we present substantially enhanced MSC/NASTRAN performance results using new sparse solvers, fully optimized for Compaq's test 64-bit Alpha systems. The combination brings true supercomputer power to the user, and offers the capacity to process a large number of analyses and the capability to solve large simulations fast and affordably, with direct benefit in time-to-market and product quality. The technologies used for CPU, system, and solver performance optimization, and the improvements achieved, are discussed and quantitative comparisons are made.

PARTNERING FOR SUCCESS (Acrobat 33K) #0999, 5 pgs.
John Hobday--British Aerospace Airbus Limited

ABSTRACT: In order for the Airbus Concurrent Engineering (ACE) project, and subsequently the next major Aircraft program to achieve ambitious targets of time and cost reduction, it was recognised that a substantially different and closer relationship with our IT Partners would be necessary. Partnerships were initially discussed with Computervision and Hewlett Packard, the aspiration of win-win scenarios and comfortable relationships proved difficult to achieve. In the early years of the ACE project (95-98) a lot was learnt by all involved about what Partnerships really were and the considerable effort and conciliation required by all involved to make them effective.

The ACE project has recently undergone a major re-organisation (1^stQtr99) which has coincided with the widening of the project to include other IT Partners to support our objective of delivering process improvements across the entire A/C Lifecycle from product concept to demise.

This presentation now monopolises upon the learning of the past three years. I shall attempt to communicate our vision of a generic Partnership Operating Framework, which will be contractually binding for both Airbus and our IT Partners and is the process reference standard against which our mutual engagement and respective performance in support of the Partnership modus operandi will be measured.

THE PRIMARY STRUCTURE OF COMMERCIAL TRANSPORT AIRCRAFT WINGS: RAPID GENERATION OF FINITE ELEMENT MODELS USING KNOWLEDGE-BASED METHODS(Acrobat 358K) #2999, 13 pgs.
Dave Rondeau and Kostas Soumilas--British Aerospace Airbus

ABSTRACT: Early decisions in the development of a new aircraft programme depend critically on the availability of high fidelity structural analysis to validate design principles and quantify the effect of design changes on structural performance. This paper details British Aerospace’s (BAe) progress in the development of a tool to produce MSC/NASTRAN data decks of commercial transport aircraft wings, in hours, rather than months. The tool is integrated into British Aerospace Airbus’ Generic Transport Aircraft (GTA) knowledge-based design tool, created using the ICAD Design Language.
The GTA knowledge-based design tool enables a project team to design, analyse and optimise the primary structure of civil aircraft wings before creation and submission of MSC/NASTRAN decks. The tool rapidly produces consistent, high quality designs enabling several concepts to be considered during preliminary design 1 . It integrates surface geometry, structural layouts, 3D solid modelling, structural analysis, optimisation, manufacturability, weight and cost prediction to enable multi-disciplinary optimisation to be exploited. Recent developments have enabled the production of loads loop finite element (FE) models for a number of projects in a fraction of the time previously required.
The use of feature based modelling is also discussed, showing examples of where FE models of irregular assemblies, such as aircraft cockpit structure, can be rapidly generated. An example is shown using feature based methods to model the undercarriage attachment structure of a large civil transport aircraft.
The paper concludes that, using knowledge-based systems, it is now feasible to consider finite element modelling of wing primary structure to a level of detail previously considered impracticable during preliminary design. It also suggests that it is practical to use the same tools to establish mass/stiffness distributions throughout pre-production phases of the aircraft design cycle.

RELIABILITY ANALYSIS OF BGA PACKAGES- A TOOL FOR DESIGN ENGINEERS
(Acrobat 455K) #3599, 6 pgs.
James W. Jones, Jason Li--The MacNeal-Schwendler Corp.
Yuichi Yamazaki, Jidong Yang--The MacNeal-Schwendler Corp., Japan Ltd.
Masaki Shiratori--Yokohama National University
Qiang Yu--Yokohama National University

ABSTRACT: An innovative design and analysis procedure has been developed by The MacNeal-Schwendler Corporation (MSC) that enables the design engineer to perform analysis of Ball Grid Array (BGA) packages in an order of magnitude less time than was previously required by experienced analysts. This procedure captures the analytical expertise of the experienced analyst and makes it available to the design engineer with a minimum of training required.
This is accomplished using MSC's Acumen toolkit concept. MSC/Acumen is a unique programming procedure, which serves as an interface to the MSC/PATRAN pre- and post-processor. MSC/Acumen utilizes HTML programming to create the look and feel of a website devoted to a specific analytical problem. The expertise of the analyst as well as company procedures, processes and other, often proprietary, requirements, are captured by the MSC/Acumen developer.
The design engineer creates the analytical model from icon picks and a selection of pre-defined model components. Material properties are contained in the MSC/Acumen program as well as loading conditions, boundary conditions, and other analytical requirements. The design engineer needs not have an understanding of finite-element analysis to create the models or apply the loading and boundary conditions. The loading sequence is also pre-defined based upon the procedures and practices developed by the analysts or experts responsible for detailed analytical evaluations of such components. Life prediction techniques based upon large strain and creep analysis are used to calculate the location of failure and the number of allowable loading cycles. These techniques are well justified by extensive fatigue data at one of the authors' laboratories at Yokohama National University.

THERMAL ANALYSIS OF A COOLING SYSTEM USING FORCED CONVECTION
(Acrobat 130K) #3099, 14 pgs.
Jan Rune Nilssen --The Norwegian Defense Research Establishment

ABSTRACT:The objective of this paper is the thermal analysis of a cooling system for a High Power Traveling Wave Tube Amplifier by using forced convection. This cooling system is an integrated part of an Electronic Warfare (EW) suite in The Royal Norwegian Air Force’s EW training aircraft.
The analysis uses MSC/PATRAN for modeling and MSC/NASTRAN for the thermal analysis. Later versions of MSC/PATRAN has made it much easier for a design engineer to perform a preliminary thermal design than before. The paper will also show hand calculated values needed to run a thermal analysis with MSC/NASTRAN.
A comparison between analysis results and results from extensive laboratory testing of the actual device are made.

MSC/NASTRAN & MSC/PATRAN

ANALYSIS OF AN AIRCRAFT CARGO NET BARRIER USING MSC/NASTRAN
(Acrobat 228K) #4999, 15 pgs.
Alexander Rutman, Ph.D., Adrian Viisoreanu, Ph.D., Gary Cassatt, and John Caiazza--Boeing Commercial Airplane Group

ABSTRACT: Aircraft cargo net barriers are designed to arrest the cargo and protect the cabin crew during a survivable crash landing. Compared with metallic or composite aircraft structures, cargo nets are extremely flexible and develop large displacements under loading, making their behavior essentially non-linear and creating convergence problems. This paper presents modeling techniques and cargo net analysis strategy for MSC/NASTRAN solution 106. Parametric studies address the influence of the net initial shape and net - cargo interaction under crash landing conditions.

APPLICATION OF STRUCTURAL OPTIMIZATION ON REDESIGNING THE FRENCH-BRAZILIAN MICRO SATELLITE (Acrobat 163 K) #6399, 14 pgs.
F. M. N. Ravetti, M. Kataoka-Filho and C. A. Vidal--Insituto Nactional de Pesquisas

ABSTRACT:The French-Brazilian Micro Satellite (FBMS) is a scientific satellite, which will be piggyback launched by the rocket Ariane 5. Its most critical design constraints are: the lower bound of 40.0 Hz on the first natural frequency, in order to avoid coupling between the rocket excitation modes and the natural vibration modes of the satellite; and the upper bound of 10.5 kg on the structural mass. The structure of the FBMS is composed of a cylindrical aluminum alloy adapter for connection with the rocket, and eight sandwich panels (each composed of three layers) that define its topology. In this paper, we show the importance of structural optimization and design sensitivity analysis in the redesign cycles of Space Structures, by presenting all the steps taken and the difficulties encountered as we tried to maximize the first natural frequency from the low value of 18.78 Hz obtained with the first trial design, while maintaining the structural mass bellow the predefined upper bound. All the modal and sensitivity analyses as well as the optimization steps were performed using MSC/NASTRAN. The design variable space for the structural optimization steps was composed of the thicknesses of the faces and core of the sandwich panels.

AUTOMATIC 3D MESH GENERATION CONFORMING A PRESCRIBED SIZE MAP, (Acrobat 1.35MB) #4197, 23 pgs.
Paul Louis George--INRIA, Gamma Project, France
Houman Borouchaki--UTT, GSM-LASMIS, France

ABSTRACT

A BREAKTHROUGH IN PARALLEL PERFORMANCE IN MSC/NASTRAN V70.7
(Acrobat 98 K) #5599, 9 pgs.
Louis Komzsik, Stefan Mayer and Petra Poschmann--The MacNeal-Schwendler Corporation

ABSTRACT: More than a decade ago MSC offered the first parallel production system of MSC/NASTRAN. During this decade MSC has intensified its effort on parallel MSC/NASTRAN and is now ready to deliver MSC/NASTRAN V70.7, which contains very important new parallel features. This paper describes these exciting features and provides preliminary performance results for V70.7. We believe that this system marks the best in parallel MSC/NASTRAN performance ever and presents a breakthrough in parallel computing in our market.

CATIA ATTRIBUTE TRANSFER TO MSC/PATRAN FOR AIRCRAFT STRUCTURES (Acrobat 293K) #3899, 7 pgs.
Dave Swabey--GKN Westland Helicopter

ABSTRACT: GKN Westland Helicopters has adopted Catia as the main depository of geometric data. All future aircraft will be generated with Catia as Exact Solids on a One-Model per Part Basis. This data is then used within Catia to create a FE Degenerate Geometry Assembly of the Parts within an Aircraft Module. The Part Information and attributes, such as plate thickness and beam cross sections, are stored as Attribute Data with Catia. This information is then transferred to Patran via. Bespoke software that extracts the Attribute Data from Catia and writes a data file which is imported into Patran.

Within Patran our PCL code is used to import the Attribute Data and store it as Properties, Arbitrary Beam Sections and Client Data. As the Global Location of the Beam Cross Sections are known then the Beam Orientation and Offsets can be generated automatically and assigned to the properties.
To assist in the checking and use of this data we have generated our own PCL Functions to access and Display this Data, and in particular to display the Beam Cross Sections on the Geometric Curves imported from Catia.
Currently GKN Westland Helicopters is involved in a project, which is using data from Catia for the definition of the Aircraft Structure. As this is an existing aircraft the Catia Definition is a mixture of Exact Solids and Surfaces. This project will give us a good test platform with which to evaluate the process, highlight any problems and determine the best practice methods to be used in future projects.

DETERMINATION OF NONLINEAR STIFFNESS COEFFICIENTS FOR FINITE ELEMENT MODELS WITH APPLICATION TO THE RANDOM VIBRATION PROBLEM(Acrobat 163K) #6199, 14 pgs.
Alexander A. Muravyov--NASA Langley Research Center

ABSTRACT:In this paper, a method for obtaining nonlinear stiffness coefficients in modal coordinates for geometrically nonlinear finite-element models is developed. The method requires application of a finite-element program with a geometrically non-linear static capability. The MSC/NASTRAN code is employed for this purpose.
The equations of motion of a MDOF system are formulated in modal coordinates. A set of linear eigenvectors is used to approximate the solution of the nonlinear problem. The random vibration problem of the MDOF nonlinear system is then considered. The solutions obtained by application of two different versions of a stochastic linearization technique are compared with linear and exact (analytical) solutions in terms of root-mean-square (RMS) displacements and strains for a beam structure.

DEVELOPMENT OF AN AUTOMATED, FREE-BODY FORCES CONSTRUCTOR FOR C-2A(R) AIRFRAME STRUCTURAL ANALYSIS(Acrobat 260K) #4199, 15 pgs.
Kris Wadolkowski--Aerostructures, Inc.
Leigh-Ann Waughtel-- Naval Aviation Depot

ABSTRACT: In carrying out their responsibilities for providing maintenance support for the C-2A(R) Carrier On-Board Delivery (COD) aircraft, the Navy's Research and Engineering Office was faced with the problem of determining proper boundary conditions for their detailed stress models. A commonly used method involves extracting the boundary conditions for a local area from a larger loads-model and it was this approach that was adopted for the development of an automated procedure. In preparation for this effort, an MSC/NASTRAN loads-model of the C-2A(R) airframe was developed from Grumman's ASTRAL model and an interrogable database of internal forces was created. A Windows-based program, with an MSC/NASTRAN for Windows interface feature, was developed to access this database and generate boundary forces for the user-specified region. Output from this program is in MSC/NASTRAN format card images and includes a "starter" file for the detailed stress model.

DIAG-2 GEOMETRIC NON-LINEAR PARAMETERS CALCULATION FOR DIAGONAL TENSION SIMULATION USING MSC/NASTRAN(Acrobat 163K) #5399, 14 pgs.
Klaus Otto Schwarzmeier--EMBRAER-Empresa Brasileira de Aeronautica S/A

ABSTRACT: The analysis of Diagonal Tension effects on a thin walled reinforced shell structure that buckles under compression/shear loadings is essential. DIAG2 program was written to simulate the non-linear effects
due to the skin buckling (under compression/shear) of cylindrical structures with frames (ribs) and
stiffeners. The original structure model is therefore changed to simulate the post-buckling behavior of the
structure.

INTEGRATING MSC SOFTWARE AND CADSA PROGRAM FOR THE AIRCRAFT DETAIL STRESS ANALYSIS (Acrobat 98 K) #4499, 12 pgs.
Ming Chiu,Tian-Sheng Wu, Chun-Hui Lee,and Nan-Horng Lee--Aerospace Industrial Development Corporation

ABSTRACT: AIDC has involved several international cooperation projects for commercial airplane for several years. From CAE viewpoint, Structural detail stress analysis and certification analysis reports (such as: FAA/JAA Certification) are two major time and manpower consumer. So, Standardization and automation can further improve analysis processes and shorten working time. Therefore, AIDC has developed a program, Computer Aided Detail Stress Analysis (CADSA), cooperated with MSC/NASTRAN and MSC/PATRAN packages to do the detail stress analysis. This program provided a fast and efficient method to help analyst to do the detail stress analysis and to output formal stress reports. This CADSA program has been applied to some International Cooperation Project, and it has been proven to be very significant benefit on cost reduction and best quality.

INTERFACE ELEMENTS IN GLOBAL/LOCAL ANALYSIS - PART 2: SURFACE INTERFACE ELEMENTS, (Acrobat 1.3MB) #4397, 18 pgs.
John E. Schiermeier--The MacNeal-Schwendler Corporation
Jerrold M. Housner and Jonathan B. Ransom--NASA Langley Research Center
Mohammad A. Aminpour--Applied Research Associates, Inc.
Jefferson Stroud-- NASA Langley Research Center

ABSTRACT: When performing global/local analysis, the issue of connecting dissimilar meshes often arises, especially when refinement is performed. One method of connecting these dissimilar meshes is to use interface elements. In the previous Part 1, curve interface elements, implemented in MSC/NASTRAN Version 69 for shell and beam p-element edges, were presented. In the current Part 2, surface interface elements, being implemented in MSC/NASTRAN for solid and shell p-element faces, are presented with examples.

INTERFACE ELEMENTS IN GLOBAL/LOCAL ANALYSIS--PART 3: SHELL-TO-SOLID TRANSITION
(Acrobat 520K) #5699, 17 pgs.
John E. Schiermeier and Rajendra K. Kansakar--MSC
Jonathan B. Ransom and W. Jefferson Stroud--NASA Langley Research Center
Mohammad A. Aminpour--Applied Research Associates, Inc.

ABSTRACT: When performing global/local analysis, the issue of connecting dissimilar meshes often arises, especially when refinement is performed. One method of connecting these dissimilar meshes is to use interface elements. In the previous Parts 1 and 2, curve and surface interface elements, implemented for p-element edges and faces in MSC/NASTRAN Version 69 and 70.5, respectively, were presented. In the current Part 3, the shell-to-solid transition, being implemented to connect dissimilar p-element edges with p-element faces, is presented with examples. This transition completes the set of interface tools for global/local analysis.

LOCAL ANALYSIS OF RIVET HOLES USING THE LINEAR GAP TECHNOLOGY OF MSC/NASTRAN
(Acrobat 423K) #5799, 24 pgs.
John McCullough--Bell Helicopter TEXTRON, Inc.
Lance Proctor--The MacNeal-Schwendler Corporation

ABSTRACT:Local analysis of bearing stresses at rivet locations in helicopters provides the information needed to prevent cracks which could lead to catastrophic failures. The analysis has typically been done using nonlinear methods, which can lead to excessive run times. The "linear gap" technology introduced in MSC/NASTRAN V70.5 linear static solution (SOL 101) can be used to assess the bearing stress regions of the skin in an efficient manner. This paper will introduce the methodology and strategies of implementing linear gaps to solve bearing stress problems.

METHODOLOGY FOR CONNECTING STRUT LOADS CALCULATIONS DURING ASSEMBLY AND LAUNCH SEQUENCE OF TWO SPACE STATION MODULES(Acrobat 65K) #5899, 13 pgs.
Sanjay Patel--The MacNeal-Schwendler Corporation

ABSTRACT: This paper outlines the solution method for calculating residual loads in the connecting members (struts) of two space station modules during assembly and launch process using MSC/NASTRAN geometric nonlinear capability. Use of geometric nonlinear capability is essential since, the assembly and launch process the loads and boundary conditions are changing at each step causing the energy redistribution during the process. The process is demonstrated using a small problem and a realistic looking space structure.

MODAL ANALYSIS- AN ELEGANT SOLUTION(Acrobat 260K) #5299, 19 pgs.
Ir. J.J. Wijker, Ir. F.M. Maitimo, and Ing. C.J. de Haan--Fokker Space B.V.

ABSTRACT:In FEM analyses for large and complex structures small structural elements are mostly
modelled by scalar elements. These scalar elements represent either stiffness or mass
properties. In a linear bifurcation analysis, not only the stiffness matrix but also the
geometrical stiffness matrix is needed. However, scalar stiffness elements, as well as GENEL
elements and DMIG stiffness input do not possess such geometrical stiffness matrices.
Therefore these elements obstruct the buckling analysis. To overcome this problem, a non-linear
analysis in conjunction with a classical normal mode analysis is proposed. Zero
eigenvalues will define the buckling load and associated buckling mode. The approach will be
discussed in this paper and will be illustrated with the buckling analysis of an in-plane loaded
simplified deployed solar array.

NEW STANDARDS BASED DATA EXCHANGE "BRIDGE" FOR DESIGN (CAD), ANALYSIS (CAE) AND MANUFACTURING (CAM) OF COMPOSITE STRUCTURES (Acrobat 130K) #4099, 18 pgs.
Keith Hunten--Lockheed Martin Tactical Aircraft Systems (LMTAS)
John Klintworth and Tom Mac-- MacNeal Schwendler Corporation (MSC)
Narendra Pitre--Geometric Software Services Co., Ltd. (GSSL)
Tom Mack-- MacNeal Schwendler Corporation (MSC)

ABSTRACT: ISO/STEP Standards are providing international product data exchange models and versioning procedures for the purpose of capturing and sharing more complete enterprise-wide design, analysis and manufacturing data. In particular, the STEP AP209 Standard (presently at Draft International Standard (DIS) status) is focused on the product design and analysis (simulation) disciplines, and provides for data exchanges that include:

design geometry, with its associated configuration management (CM) data

idealized geometry, with its associated detailed finite element models and analysis results (FEM/FEA), including associated analysis version control data and critical associations back to the parent design geometry and CM data

composite material design and analysis details such as ply and zone shape geometry, ply laminate table stacking sequences, zone laminate percentage ply tables, composite analysis material models, and ply layer analysis results (i.e., "material structure-inside-a-structure" detailed definitions)

The benefits of AP209 over current practices are improved quality of the data exchange, automation (speed), and cost sharing via ISO Standard’s collaborations between partners and suppliers.
LMTAS has selected AP209 as a preferred approach for the integration of CAD, CAM and CAE software tools (in particular MSC/PATRAN&NASTRAN, CDT/FiberSIM, and Dassault Systemes CATIA) to meet its composite structural design and analysis process requirements. LMTAS has defined a pilot production implementation scenario, which will be used to demonstrate the robustness and completeness of this multi-discipline dynamic data exchange process, using AP209. This paper documents the role MSC/PATRAN will play in this industrial scenario demonstration, using new product features which have been added to MSC/PATRAN to meet this next generation CAD/CAM/CAE composite structures integrated process.

THE ON-ORBIT THERMAL-STRUCTURAL ANALYSIS OF THE SPACECRAFT COMPONENT USING MSC/NASTRAN
(Acrobat 98K) #5999, 8 pgs.
Lihua Zhang andYuegen Chen--Beijing Institute of Spacecraft System Engineering

ABSTRACT:The predicting of thermally induced structural responses of high precision spacecraft components operating in space environment is a complex and interdisciplinary problem. Mainly using the MSC/NASTRAN software, an integrated resolution for the on-orbit thermal-structural response analysis of the spacecraft antenna reflector was presented in this paper. A unified finite element model was used in all associated analyses, including on-orbit heating loads analysis, view factor calculating, thermal analysis to obtain the temperature distributions, structural analysis to obtain thermally induced distortions as well as the best-fit analysis of the distorted reflector.

OPTIMIZATION OF AERO-STRUCTURES USING MSC/CONSTRUCT (Acrobat 15.6 MB) #5099, 24 pgs.
Gerald Himmler, Annett Kalmutzke, and Dr. Hans Sippel--MSC Germany
Walter Huber--MTU Germany

ABSTRACT:Aircraft and jet engine development requires being economical and reliable. A lot of efforts are taken to reduce the Direct Operating Costs (DOC) and to increase the payload of the aircraft. Therefore it is worth to lower the weight even on small parts. The next step is to reduce the time to market. New procedures like the Simultaneous Engineering come up where the analyst is already integrated into the concept phase of the product development process. Efficient methods of working require powerful optimization algorithms to be provided in addition to the discrete methods (FEM/BEM) proved to support the engineer in the draft and design phase.
MSC/CONSTRUCT provides an exceptionally fast and easy - to - use conceptional design tool for design engineers and analysts consisting of two options:

MSC/CONSTRUCT Topology distributes material within a design space envelope based on the optimum load path.
MSC/CONSTRUCT Shape is a non parametric shape optimization, which homogenizes the stress distribution

MSC/CONSTRUCT is available since late 1997 and is very well accepted within the automotive industry.

MSC/CONSTRUCT V3.0 will be released in Q2/99. Major highlights are:

Eigenvalues as Objective Function
Support of Cyclic Symmetry SOL 114
Support of single level superelements (SESET)
Midside Node Elements in Shape Optimization
Update of the Graphical User Interface (GUI) of MSC/PATRAN
Mesh Smoother within MSC/PATRAN

RANDOM RESPONSE ANALYSIS OF PRE-STRESSED STRUCTURES USING MSC/NASTRAN
(Acrobat 33 K) #5199, 5 pgs.
Xu Xiaocheng--China Academy of Launch Vehicle Technology

ABSTRACT:There are the static load, the thermal load and the dynamic load acting on a
vehicle structure simultaneously. Hence, the research of design method based on accounting for the coupling effects of the static load, the thermal load and the dynamic load is necessary and important. The random response analysis of pre-stressed structures is one of key problems in this research.The random response
analysis of pre-stressed structures using MSC/NASTRAN has been explored, the solution steps and key points are given in this paper. First the modal analysis of pre-stressed structures is done using the nonlinear static solution sequence SOL106,then the random response analysis of pre-stressed structures is completed by the RESTART method and using the frequency response analysis solution sequence SOL111.The verification of this method using some examples is also given in this paper.

SENSITIVITY EVALUATION ON SPHERE ATTACHMENT SHEAR STRENGTH, (Acrobat 150KB) #4297, 8pgs, color
T. E. Wong and H. K. Jew--Hughes Aircraft Company

ABSTRACT

SHAPE OPTIMIZATION IN MSC/NASTRAN AND MSC/PATRAN(Acrobat 358 K) #4899, 15 pgs.
Lance Proctor--The MacNeal-Schwendler Corporation

ABSTRACT: This paper provides a method for design shape optimization using MSC/PATRAN and MSC/NASTRAN. MSC/PATRAN provides the Graphical User Interface (GUI) to pre-and post-process shape optimization parameters and results. MSC/NASTRAN is used to solve the model and optimize the shape of a structure. This paper is not intended to be a comprehensive review of optimization theory, but rather it is intended to provide a practical process to solving real engineering problems. Two example problems will be used to show the process; one example will use shape optimization only, and one will use both sizing and shape optimization simultaneously.

STABILITY ANALYSIS OF PLATES AND DOUBLY CURVED SHALLOW SHELLS USING FINITE ELEMENT METHODS AND APPLICATIONS OF MSC/NASTRAN(Acrobat 390K) #5499, 16 pgs.
Ricardo Nonato Pereira--EMBRAER
Maher N. Bismarck-Nasr--Instituto Tecnologico de Aeronautica, ITA

ABSTRACT: A variational formulation of doubly curved shallow shells is presented. The analysis used Reissner’s two-field variable variational principle with the transverse displacement w and Airy stress function F as field variable. Euler-Lagrange equations and boundary conditions are obtained. A finite element based on this variational principle preserving C⁽¹⁾ continuity is formulated, and your eigenvalues for free vibrations and buckling analyses are abtained. Applications for free vibrations and buckling analyses in MSC/NASTRAN model are given as well as yours respective geometry shape. Several numerical calculations are presented. The results obtained are discussed and are compared with previous analytical solutions and numerical calculations.

THERMAL DESIGN ANALYSIS OF A SATELLITE WITH ARTICULATING SOLAR PANELS
(Acrobat 1.7MB) #3999, 13 pgs.
Dieter Roos--MAN Technologies
Alan I. Diner--MacNeal-Schwendler Corporation

ABSTRACT: Nearly all satellites have articulating components such as solar panels or antennas that cause the geometry of the spacecraft to vary during the orbit. MAN Technologie AG is currently in the preliminary design phase of a constellation of communication satellites. These satellites are earth oriented, except for the solar panels which are gimbaled with two axes of rotations to keep them perpendicular to the solar vector. In the proposed satellite design, the proximity of the solar panels to the radiators makes it necessary to consider the effects of the orbit-varying geometry on the absorbed heat loads and radiation network. This paper describes the orbital thermal analysis of such types of satellites performed using the TRASYS interface in MSC/PATRAN THERMAL. This system proved to be an efficient simulation tool for thermal analysis of a satellite with a complex articulating motion during the various orbits.

TRANSIENT BLAST ANALYSIS OF THE GALAXY ECOS HULD (Acrobat 1.8MB) #6299, 28 pgs.
Ashok K. Singh

ABSTRACT: A transient blast analysis of the Galaxy ECOS Hardened Unit Load Device (HULD) is performed by applying the nonlinear transient analysis algorithm of the MSC/DYTRAN program. The transient internal pressure distributions on each of the surfaces are obtained from ISO 6517 representing the C4 explosion in a partially filled container. The HULD is made of GLARE material which has alternating layers of aluminum and high strength fiberglass. This report contains a description of the model, the special modeling features, the material properties, the transient loading applied, a discussion of the results, and some conclusions.

UNCERTAINTY ANALYSIS AND DESIGN WITH MSC/NASTRAN AND PROMENVIR
(Acrobat 1 MB) #4399, 15 pgs.
Enrique Marchante --Department of Analysis and Studies. CASA

ABSTRACT:The intensive use of Finite Element Techniques in structural analysis has been accompanied by the increase in mesh density, sometimes reaching the limits of the current computer resources. The intention is to increase the model accuracy. Nevertheless, to consider data uncertainties in the analysis has been consistently ignored in the past. As a form of compensation, conservative assumptions such as, for example, reduced values for the material strength characteristics, minimum values for dimensional tolerances or factors of safety in the loads, are being considered. This approach covers some sources of uncertainty but others are traditionally ignored, as for example: Youngs modulus. Simulation techniques are the only general method to account for uncertainties, but its application to structural analysis with finite elements has been impossible in the past due to the unavailability of computational resources. Today, the resources are available and the technology exists and is implemented in the PROMENVIR system. It allows to account for uncertainties in the wide range of analysis presently available in MSC/NASTRAN. The general applicability of this methodology and the versatility of the environment is shown via three examples. The first one is oriented to show the possibilities to account for data uncertainty at analysis level. The second one focused on model updating, by definition of uncertain mobile model parameters. The third one deals with the uncertain design, in which the design parameters are treated as uncertain variables.

USING MSC/NASTRAN AND LMS/PRETEST TO FIND AN OPTIMAL SENSOR PLACEMENT FOR MODAL IDENTIFICATION AND CORRELATION OF AEROSPACE STRUCTURES
(Acrobat 195K) #6099, 12 pgs.
Tom Van Langenhove and Marc Brughmans--LMS International

ABSTRACT: As time-to-market also in aerospace begins to play a crucial role, accurate predictions and simulations of the behavior of new structures based on analytical models become more and more important. A modal identification must be performed to obtain modal parameters which can be compared with the pre-test analytical results using correlation techniques. Based on the outcome of the correlation analysis, the analytical models must be ‘updated’ such that they more accurately predict the actual test results. Since often the time is lacking to validate each component separately, it is a great challenge to define an optimal sensor set for the complete assembly, including internal components. Also, new materials, hyper-new design and not to forget the ever growing model sizes do not make the job more easy. This paper approaches the sensor placement problem from the standpoint of the structural dynamicist who must use the modal parameters obtained during a ground vibration, or eventually an on-orbit test, to perform a test-analysis correlation and updating analysis. The paper also explains which tools are available to make his life easier. A good choice is crucial not only for experimental observability of the dynamic behavior of the structure, but also for the accuracy of the reduced matrices (for orthogonality calculations). Eventually it will help also the modal analysist during his tests and it will make the (often-difficult) geometric correlation obsolete.

MSC/PATRAN & Other MSC Products

BATCH COMPUTING IN CLIENT/SERVER IT-INFRASTRUCTURES USING LSF AND THE MSC/ANALYSIS MANAGER, (Acrobat 19KB) #3297, 4 pgs.
Klaus-Peter Wessel--Daimler Benz Aerospace Airbus

ABSTRACT

DESIGN OF AN INTELLIGENT STRUCTURAL QUALIFICATION ENVIRONMENT USING MSC/PATRAN, (Acrobat 175KB) #3197, 12 pgs.
N.J. Dullaway and A.J. Morris--Cranfield University, England.

ABSTRACT

OPTIMIZING THE ENGINEERING PROCESS AT ROCKETDYNE USING MSC/MVISION, (Acrobat 217KB) #3097, 14 pgs, color
Terry Wong--Boeing North American, Inc.

ABSTRACT

THE USE OF AUTOMATIC TET MESHING WITHIN A CONCURRENT ENGINEERING ENVIRONMENT #2997cr (Acrobat 7MB, color) or #2997bw (Acrobat 1.44MB, b&w;), both 15 pgs.
C.P. Griffiths--British Aerospace

ABSTRACT

1993-1999 MSC Users' Conference Proceedings

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