MSC Software Corporation

1993-1999 MSC Users' Conference Proceedings

Aeroelasticity

AERODYNAMICS-STRUCTURES INTERACTION IN AIRFRAME DESIGN, (Acrobat 999K) #1097, 11pgs.
V.B. Venkayya and V.A. Tischler--Wright-Patterson AFB, Ohio ABSTRACT: Aerodynamics and structures interaction play a critical role in airframe design. It becomes even more significant when viewed in the context of emerging Multidisciplinary Design Optimization (MDO), because the fidelity of the aerodynamic and structures models improves the reliability of the optimal solutions. The primary airframe components affected by the aero-structures interaction are lifting surfaces such as: wings, canards, fins, vertical and horizontal tails, etc. The flexibility effects on the aerodynamic load predictions on modern aircraft can be very significant. They effect both the steady and unsteady aerodynamic behavior as well as the stability aspects. There is a growing interest in both the national laboratories and in industry to develop Aero-Structures Interaction (ASI) tools.

AEROELASTIC ANALYSES IN "PZL-MIELIC" USING MSC/NASTRAN (Acrobat 293K) #2199, 13 pgs.
Wojciech Chajec--Aircraft Factory "PZL-MIELEC" Ltd.

ABSTRACT: Presented here is implementation of MSC/NASTRAN system in aerolastic computation practice in "PZL-Mielec". This computation system is compared with our own old flutter calculation programs. Discussed are advantages and also difficulties caused overcoming of old habits and the fact that MSC/NASTRAN is an universal system not only for flutter calculation. PC programs which were created specifically to overcome the difficulties are presented additionally. A few interesting results of calculations are also showed.
Contents
1. Short view on flutter calculation methods in "PZL-Mielec" before MSC/NASTRAN based on calculated (beam-like structural calculation model) or in GVT measured modes.
2. Implementation of MSC/NASTRAN system.
3. Description of additional programs for PC - useful for aeroelastic calculation in MSC/NASTRAN, prepared in "PZL-Mielec"

programs for natural mode and flutter mode animation and drawing

program for drawing and sorting flutter calculation results: g(V), f(V)

graphic preprocessor for aerodynamic data generation and static pressure distribution drawing (for static aeroelasticity calculation)

some modification of propf.for program (in propa.v68 - alter) for aerodynamic forces in whirl-flutter calculation

4. Examples of aeroelastic calculation in "PZL-Mielec" and problems
5. Conclusions

BALANCED CONTINUOUS TURBULENCE GUST LOADS USING SOLUTION 146(Acrobat 195K) #2099, 13 pgs.
James E. Locke, Sr. Technical Specialist--Raytheon Aircraft Company

ABSTRACT: This paper describes and illustrates a method to obtain balanced (time-correlated) continuous turbulence gust loads using MSC/NASTRAN Solution Sequence 146 (SOL 146). Continuous atmospheric turbulence is modeled in the frequency domain as a power spectral density (PSD) function using the von Karman gust PSD. SOL 146 is used to obtain the complex frequency response for each load quantity. Balanced loads are determined using the equations of random process theory. Maximized load quantities correspond to RMS values determined from response PSD functions. Balanced loads for each maximized load correspond to scaled cross-correlation functions. Results are presented for a typical gust load condition.

COMPUTATION OF DYNAMIC LOADS ON AIRCRAFT STRUCTURE DUE TO CONTINUOUS GUST USING MSC/NASTRAN, (Acrobat 819K) #0797, 17 pgs.
Eduardo A. Rodrigues and Mauro T. Kamiyama--EMBRAER S.A., Brazil

ABSTRACT: The computation of gust loads on the structure of an aircraft is part of the engineering work during the development and certification phases of a new project. The present work describes the methodology used at EMBRAER to compute dynamic loads caused by atmospheric continuous gusts. The mathematical formulation assumes that the gust phenomenon is described as a stationary random process and that the aircraft dynamics is linear. MSC/NASTRAN is used for obtaining the dynamic system modal data by means of SOL1O3 (normal modes solution), and the modal amplitudes necessary to generate the dynamic system frequency-response functions by means of S0L146 (aeroelastic response solution). An example is given in which the methodology is applied to a modern jet aircraft.

COUPLED AEROELASTIC ANALYSIS OF A FREE FLIGHT ROCKET(Acrobat 228K) #2399, 11 pgs.
D.S. Livshits, S. Yaniv--IMI - Israel Military Industries
M. Karpel--Technion - Israel Institute of Technology

ABSTRACT: Aeroelastic analysis of rockets is an essential part of their design procedure. In most cases, the analysis is limited to calculation of the divergence velocity, sometimes leading to unrealistic prediction of the rocket response. The coupled dynamic aeroelastic analysis approach is established to allow for the consideration of coupling effects between the rocket spin, its imperfection parameters and the airflow. The approach is based on integrated dynamic aeroelastic/CFD modeling methodology

COUPLING FLIGHT CONTROL SYSTEM DYNAMICS WITH AEROELASTIC EQUATIONS OF MSC/NASTRAN, (Acrobat 207K) #997, 11 pgs.
Yan Mursal, Pipit Puspitasari, and Nineu Disyani--Aircraft Design Div.,PT.IPTN ABSTRACT: This paper presents development of a procedure to include flight control system dynamics with aeroelasticity in MSC/NASTRAN. The specific application is on flutter analysis of a twin engine propeller aircraft with the yaw damper flight control system ON. The flutter analysis is performed using the PK-method. The yaw damper transfer functions are introduced into the aeroelastic equations of motion through a combination of EPOINT and TF entries. One of the extra-points represents the rudder deflection resulting from the yaw damper system. The additional generalized unsteady-aerodynamic forces due to this extra-point are provided with down-washes supplied on DMI entries in the Bulk Data. The analysis results are presented on V-G and V-F diagrams for two configurations, nominal and yaw damper ON.

AN ENHANCED CORRECTION FACTOR TECHNIQUE FOR AERODYNAMIC INFLUENCE COEFFICIENT METHODS
(Acrobat 488K) #2299, 12 pgs.
Ioan Jadic, Dayton Hartley and Jagannath Girl--Raytheon Aircraft Company, Kansas

ABSTRACT: The present Enhanced Correction Factor Technique (ECFT) is intended to provide an improved solution to the classical problem of correcting the Aerodynamic Influence Coefficients (AIC) formulation produced by panel methods, such as the Doublet Lattice Method (DLM). In the case of MSC/NASTRAN aeroelastic analysis methods, provisions are made for inclusion of correction matrices which premultiply the AIC matrix in order to provide a level of accuracy of the aerodynamic forces consistent with experimental and/or CFD data. Classical techniques use a diagonal correction matrix allowing for limited correction capabilities: typically, one mode. By contrast, the present ECFT uses a full correction matrix that can handle multiple modes simultaneously, allowing a complete correction capability including any interference effects. Further, it is possible to define by means of ECFT several correction matrices that tackle nonlinearities for a given Mach number.
Several comparisons are presented which cover a wide range of application cases. The results obtained with ECFT are shown to match the input data.

INTERFACING EXTERNAL, HIGH ORDER AERODYNAMICS INTO MSC/NASTRAN FOR AEROELASTIC ANALYSES, (Acrobat 748K) #897, 18 pgs., color
Brent Whiting--Boeing Defense and Space Group
Douglas J. Neill--The MSC.Software Corporation

ABSTRACT: In the design of aircraft, it is important to have an accurate simulation of both the structural characteristics and the aerodynamic characteristics of the vehicle. For static aerodynamic loads, MSC/NASTRAN uses unsteady aerodynamics at zero reduced frequency. To utilize the accurate structural representation of MSC/NASTRAN in the computation of aeroelastic loads, it is desirable to incorporate aerodynamic and aeroelastic data into the MSC/NASTRAN solution sequence that better represents the actual geometry of the vehicle. This entails importing data that replaces or augments the unsteady data. The Boeing Company, in conjunction with MSC personnel, has prototyped an interface procedure that allows the static aeroelastic loads computations in MSC/NASTRAN to use the rigid aerodynamic forces and aeroelastic corrections from the A502 High Order Panel Method.

THE MSC FLIGHT LOADS AND DYNAMICS SYSTEM, (Acrobat 54K) #1197, 8 pgs.
Douglas J. Neill and Greg Sikes--The MSC.Software Corporation

ASTRACT: The MSC.Software Corporation (MSC) developed an aeroelastic analysis and design capability in the late 1970's and 1980's as part of MSC/NASTRAN. This capability includes flutter analysis, gust analysis and flight loads calculations. The latter is more suited to preliminary and conceptual design. As aerospace companies move to simulate the aeroelastic behavior of the vehicle early in the design cycle, however, there is a need to augment these capabilities to better fit within the current design processes. This augmentation includes new system architecture concepts, enhanced data management and model management and integrated visualization tools that understand aeroelastic models. Finally, new engineering tools need to be implemented that can better model aeroelastic phenomena at an appropriate level of fidelity for use in both vehicle design and production analysis.
This paper will present the critical requirements of the system as understood from numerous discussions with aerodynamicists, loads analysts, dynamicists and aeroelasticians in the aerospace community. Results from this work-in-progress will be presented where appropriate to illustrate the basic architecture, data flow and usage paradigms and their interaction with the aircraft design process.

Aircraft/Aero/Assemblies

LOCAL STRESS ANALYSIS OF STIFFENED SHELLS USING MSC/NASTRAN'S SHELL AND BEAM p-ELEMENTS, (Acrobat 68MB) #4797, 10 pgs.
Sanjay Patel, Claus Hoff, and Mark Gwillim--The MSC.Software Corporation

ABSTRACT: In large finite element models of aircraft structures, traditional h-elements give sufficient accuracy for most purposes, for example in vibration analysis. However, for local stress analysis of stiffened shells, h-elements may give inaccurate answers at shell-stiffener connections. The paper shows how to use p-elements at those locations where more accurate stresses are required. P-elements work with the existing h-element mesh. A few modifications of the input are necessary to convert local parts of the model into p-elements. The p-version elements improve local stresses significantly. The increase in accuracy is demonstrated on two examples of stiffened shells.

MSC DEVELOPMENTS IN AEROELASTICITY, (Acrobat 41K) #4497, 9 pgs.
Erwin H. Johnson--The MSC.Software Corporation

ABSTRACT: The MSC.Software Corporation has a long history of involvement with aeroelasticity. This paper briefly reviews past development efforts and the current capabilities in this area. Recent developments that have not been incorporated into standard documentation are given somewhat more emphasis. This paper concludes with a discussion of ongoing development activity.

MSC/SUPERMODEL A CAE DATA MANAGEMENT AND ADVANCED STRUCTURAL MODELING SYSTEM (Acrobat 1.2MB) #4597, 11 pgs., color
Greg Sikes--The MSC.Software Corporation

ABSTRACT: MSC/SuperModel supports the processes typically used in the design of large structures comprised of multiple components, typical of aircraft, jet engines, satellites, and launch vehicles. The engineering design and analysis of these large assembly structures is often conducted at the component level with multiple project engineers or project teams each responsible for a given component. In addition to modeling and simulating the performance of each individual component, the assembled vehicle performance must be verified as well. MSC/SuperModel provides an integrated engineering environment that greatly facilities the coordination and communication of engineering modeling and analysis results data among the project team(s). MSC/SuperModel is a powerful CAE process and data management system with engineering tools for advanced modeling and simulation.

RANDOM ANALYSIS USING MSC/NASTRAN ISHELL MODULE, (Acrobat 1.5MB) #4897, 13 pgs.
Mohan Barbela--The MSC.Software Corporation

ABSTRACT: MSC/NASTRAN version 70 has a new DMAP module called ISHELL that allows users to execute an external program from within MSC/NASTRAN. This module is very powerful and can be used to perform various tasks; for example, sorting, margin of safety calculation, and any data block manipulation using an external user written program. This paper briefly describes the ISHELL DMAP module and the procedure to perform random analysis using MSC/NASTRAN ISHELL DMAP module and an external program.

Aero Engines

CHARACTERIZATION OF MSC/NASTRAN & MSC/ABAQUS ELEMENTS FOR TURBINE, (Acrobat 379K) #2097, 15 pgs.
Lt. Jeff Brown--Air Force Research Lab

ABSTRACT: An accuracy study of MSC/NASTRAN and MSC/ABAQUS three dimensional element types was conducted for turbine engine blade natural frequency analysis. Linear, quadratic, hexahedral, and tetrahedral elements were used with different mesh densities in the frequency and mode shape predictions. These results were compared to bench test data and laser holographic mode shapes. Recommendations are made on the selection of finite element meshes for future analyses.

DEFLECTION ANALYSIS OF AERO GAS TURBINE STRUCTURE DURING PROTOTYPE DEVELOPMENT, (Acrobat 525K) #2197, 10 pgs.
M.Chandrasekaran and K.Ramachandra--Gas Turbine Research Establishment, Bangalore, India

ABSTRACT: This paper presents a refined finite element procedure to obtain the cold dimensions of aero engine structural assembly from the dimensions of larger hot gas flow path and also establish the operating clearances between rotor blades and casings. The effects of stiffness distribution on the circularity of casings-frames assembly and its weight optimization are also discussed.

DYNAMIC ANALYSIS OF FLEXIBLE TURBO-ROTOR SYSTEM USING SUPER-ELEMENTS
(Acrobat 130K) #1799, 14pgs.
A. Surial and Dr. A. Kaushal--Rolls Royce, Montreal

ABSTRACT:The approach presented in this paper will give an overview on the dynamic analysis of gas turbine engines. It will help a user to prepare an input file for MSC/NASTRAN in order to perform the critical speed (SOL 107) and forced response analysis (unbalance response — SOL 108) of any size rotating structure(s), taking into account gyroscopic effects using MSC/NASTRAN DMAP, ridgyroa.v705.

FINITE ELEMENT ANALYSES OF A LAMINATED BLADE RETENTION SYSTEM, (Acrobat 456K) #2297, 18 .pgs.
Dennis K. McCarthy and Robert T. Fort--McDonnell Douglas Helicopter Systems

ABSTRACT: Design of a helicopter main rotor blade retention system is a challenging problem. This critical system must reliably carry large blade loads while allowing extreme blade motions. Several different methods for blade retention systems are currently in service including laminated metallic stacks (LMS). Due to the lack of precise analytic methods laminated metallic stack systems have historically been developed through test. A methodology, developed by the authors, is presented herein to accurately predict the behavior of a LMS blade retention system. This method uses nonlinear finite element (FE) analysis to predict LMS motions and stresses. Finite element results are interrogated to obtain damage and fatigue life predictions. The analytical results are compared to test data with excellent agreement thus verifying the methodology.

HYDROELASTIC ANALYSIS OF A RECTANGULAR TANK, (Acrobat 271K) #2397, 26 pgs.
M.C. Kim and S.S. Lee--The Aerospace Corporation

ABSTRACT: A hydroelastic analysis of a rectangular tank is performed using MSC/NASTRAN. Natural frequencies of slosh modes and hydroelastic modes are evaluated, and are compared with results from other approaches as well as analytical values.

SNECMA BLADE AND DISK MESHING METHODOLOGY(Acrobat 325K ) #1699, 10 pgs.
Antoine Soeiro--MacNeal Schwendler, France

ABSTRACT:This paper will describe a consulting project that MSC France did for Snecma. This project was called time cycle reduction. We aimed at increasing the productivity of Snecma's Design Office by defining the most accurate methodology for meshing a compressor blade and disk using MSC/PATRAN.
Throughout this presentation the detailed process will be developed to explain how the time reduction was obtained.
According to what has already been done, both Snecma and MSC have great hope to enhance our first results by using MSC new tools.

STRUCTURE SIMULATION AND BLADE DESIGN OF AN AIRCRAFT ENGINE(Acrobat 1.3MB) #1899, 12 pgs.
André Ollivier--SNECMA

ABSTRACT:Structural analysis have progressed at a level such that they are now increasingly used all days in activities of mechanical engineering
Since 25 years at SNECMA, analyses have for main objective to provide in both detail and overall a knowledge of the behaviour and damage of the part, they are an help with the decision in design conception via optimization.
We are currently in a period of utilization of more and more simulations , what allows to reduce significantly the number of tests. Researches allow to develop tools simulating the behavior increasingly precisely.
These simulations have become of necessary tools, to reduce costs, to reduce cycles, to design robust. Take into account very early manufacture constraints in simulations, improved the simultaneous engineering.
It is demonstrated here after that the large use of simulation during the period of life of the product, will allow to improve them, and to answer as quickly as possible to quality and reliability needs of the companies.
Finally, it is necessary to insist on the inter-operability of tools of simulation, centered on a numerical geometrical model. This inter-operability has to accompany the concept of extended enterprise and the world cooperation necessity. These are the keys of the success of industrial products design for the next century.

VALIDATION AND UPDATING OF AN AERO ENGINE FINITE ELEMENT MODEL BASED ON STATIC STIFFNESS TESTING(Acrobat 65 K) #1999, 8 pgs.
E. Dascotte --Dynamic Design Solutions
A. Schönrock--CargoLifter Development GmbH

ABSTRACT: Today's aerospace industry uses finite element analysis in a huge variety of applications in order to optimize structures and processes before hardware is procured. Efficiencies can be enhanced and margins are reduced because external loads and the structural properties are identified with higher confidence. The accuracy of finite element analysis predictions therefore becomes more and more important and directly influences the competitiveness of the product on the market.
In particular, accurate shell element models are difficult to generate because of the inability to account for fillet radii and problems with coupling of the in-plane rotational stiffness. Another common uncertainty is the accuracy of modeling shell structure bolted flanges and especially their behaviour under large loads. These features are widely used for structural finite element modeling within the aeronautic industry.
Although modal testing has proved to provide valuable reference data for FE model validation and updating, static stiffness tests have the advantage to allow the application of large forces. In addition, static deformations are independent of the mass parameter.
To process static test data and MSC/NASTRAN analysis results and perform correlation analysis and FE model updating, appropriate methods were developed and implemented into the existing FEMtools software. This paper describes the approach and gives reference to a successful application.

Aircraft Applications

ADVANCED COMPOSITES REPAIR ANALYSIS TOOL (ACRAT) (Acrobat 64K) 1996, 12 pgs.
Thomas E. Mack--The MacNeal-Schwendler Corporation James Y. Song--USAF Advanced Composites Program

ABSTRACT

ACRAT's software system design emphasis has been focused on standardized methods of electronic data modeling and exchange; a UNIX-less process management environment which insures geometric configuration management and material release control; integration of COTS and/or public domain software wherever possible to reduce the cost of development while maximizing system functionality and reducing future costs of ownership (upgrading/porting supportability); and a single user friendly graphical user interface (GUI) capable of supporting a wide range of perspective users (field technician or expert CAE/composites engineer).

Four (4) customized database schemas (M&P, Aircraft Design, Composite Repair, Component Test) were designed and sufficiently populated to evaluate each data model's ability to meet specific ACRAT system requirements. These prototype databases, coupled with the ACRAT Executive Control System (ECS) database, represent the foundation upon which the fully self contained ACRAT software system has been built.

CALCULATION WITHIN MSC/NASTRAN OF THE FORCES TRANSMITTED BY MULTIPOINT CONSTRAINTS (MPC) AND THE FORCES GENERATED IN SUPPORT CONSTRAINTS (Acrobat 128K) 1996, 21 pgs. E. de la Fuente--Instituto Nacional de Técnica Aeroespacial (INTA) J. San Millán--Instituto Nacional de Técnica Aeroespacial (INTA)

ABSTRACT

COMBINING ACCELERATION AND DISPLACEMENT DEPENDENT MODAL FREQUENCY RESPONSES USING AN MSC/NASTRAN DMAP ALTER (Acrobat 96K) 1996, 10 pgs. Alan R. Barnett--Analex Corporation Timothy W. Widrick--Analex Corporation Damian R. Ludwiczak--NASA Lewis Research Center

ABSTRACT

EMB-145 NOSE LANDING GEAR DOOR STRESS ANALYSIS (Acrobat 1.6MB) 1996,14 pgs. Francisco K. Arakaki--EMBRAER-Empresa Brasileira de Aeronáutica Filipe K. Honda--EMBRAER-Empresa Brasileira de Aeronáutica Maria Luci P. Salomão--EMBRAER-Empresa Brasileira de Aeronáutica ABSTRACT: In the present report the structural analysis of EMBRAER's EMB-145 Aircraft Nose Landing Gear Door (N.L.G.D.) is shown. The EMB-145 Nose Landing Gear Door is attached to the aircraft fuselage through three hinges which are driven by a hydraulic actuator attached to the central hinge. The EMB-145 N.L.G.D. structure, is made of two solid prepreg carbon/epoxy laminated skins, cold bonded and fastened. Carbon/epoxy tape is used in order to avoid panel buckling and to increase the required stiffness of the Aerodynamic Smoothness Requirements for EMB-145. The hinges are machined from aluminum alloy, attached to the structure by titanium alloy bolts. The EMB-145 Nose Landing Gear Door is designed to resist the critical aerodynamical loading in normal condition and in case one of the hinges fails. The EMB-145 Nose Landing Gear Door structural analysis including finite element data, boundary conditions and acting loading are presented in this report. The present output results in MSC/NASTRAN allow one to obtain the most critical condition among all subcases very quickly, when post-processed. EVALUATION OF AN ANALYTICAL DESIGN TOOL FOR BALLISTIC DYNAMICS SIMULATION (Acrobat 672K) 1996, 13 pgs. Ashish K. Sareen--Bell Helicopter Textron, Inc. Michael R. Smith--Bell Helicopter Textron, Inc.
ABSTRACT: Usefulness of ballistic dynamics simulations as a design tool in assessing ballistic tolerance and as an aid in pretest guidance is studied. Accurate simulations of hydraulic ram, including failure mode prediction, can be useful in enhancing survivability and in guiding pretest specimen setup to ensure projectile strike and exit at critical locations, thereby minimizing the cost of expensive development tests. To understand the potential of ballistic simulation as a design tool, MSC/DYTRAN code has been evaluated at Bell Helicopter Textron, Inc. by conducting simulations using projectiles of different sizes to impact and penetrate a generic fluid-filled tank and a composite wing structure containing fuel cells. Projectile trajectory, fluid pressures in the fuel tank, and wing structural response from the analysis are compared with the measured data. The physics of the phenomenon appears to be accurately simulated, indicating that MSC/DYTRAN could be a useful design tool for enhancing ballistic tolerance.
GETTING FEA INTO THE DESIGN PROCESS: RAPID ANALYSIS OF TUBES (Acrobat 667K) #0495, 15 pgs. Raymond N. Frick, Ph.D., RE.--Pratt & Whitney

ABSTRACT:

A MSC/DYTRAN SIMULATION OF THE LYNX HELICOPTER MAIN LIFTFRAME COLLAPSE (Acrobat 480K) 1996, 19 pgs.
Marcio J. Cavalcanti--Brazilian Navy
Rade Vignjevic--Cranfield University

ABSTRACT: MSC/DYTRAN, an explicit nonlinear finite element code, was used to determine the collapse characteristics of the Lynx helicopter main liftframe, for the vertical crash case. The liftframe was modelled by the Belytschko-Tsay four node shell elements. The analysis of the influence of the collapse velocity on the component structural failure modes and a sensitivity analysis of the material failure criteria were performed. The increase in crashing velocity from 4 to 8 m/s changed the mode of structural failure from torsional buckling, to bending/axial failure. The material failure criteria, however, did not significantly affect the structure collapse mechanism nor the force vs. displacement results. The MSC/DYTRAN simulation results showed good agreement with the full scale test data.

MSC/FLIGHT LOADS AND DYNAMICS VERSION 1 (Acrobat 237K) #1198, 8 pgs.
Greg Sikes and Douglas J. Neill--The MacNeal-Schwendler Corporation

ABSTRACT: For the past year, the MacNeal-Schwendler Corporation (MSC) has been actively developing solutions to the challenges faced by our customers in the area of external loads and aerodynamic response. Through strategic partnerships with the world's leading civilian and military air vehicle manufactures, MSC has developed an in-depth understanding of our customers' needs. These efforts have lead to the development of an integrated, process-driven external loads and dynamics system called MSC/FlightLoads and Dynamics.

MSC/NASTRAN FLUTTER ANALYSES OF T-TAILS INCLUDING HORIZONTAL STABILIZER STATIC LIFT EFFECTS AND T-TAIL TRANSONIC DIP (Acrobat 768K) 1996, 10 pgs.
Emil Suciu--Gulfstream Aerospace Corporation

ABSTRACT:

MSC/PATRAN AS A PART OF A TOOL IN THE FIELD OF STATIC AND DYNAMIC AEROELASTICITY (Acrobat 1MB) 1996, 8 pgs. Jari Hyvärinen--Anker-Zemer Engineering AB Per Kjellgren--Anker-Zemer Engineering AB ABSTRACT: This paper uses two measures for stability when studying aeroelastic behaviour in problems which require Non-linear fluid mechanics modelling for the solution. One measure is defined for static stability and the other for dynamic stability. The simulation performed on the fluid-structure interaction of a 2D ellipse in a sub critical Reynolds number flow field is shown in this paper. PARTICULARITIES OF SINGLE SHEAR PIN JOINTS MODELING FOR MSC/NASTRAN (Acrobat 3.5MB) #3898, 12 pgs. Adrian Viisoreanu--Boeing Commercial Airplane Group Kris Wadolkowski--Aerostructures, Inc. ABSTRACT: Inspired from the analysis of aircraft engine mount fittings, this paper presents techniques applicable to the solid modeling of single shear pin joints in MSC/NASTRAN. A parametric study describes the influence of some joint geometry parameters on the stress and bearing load distribution along the pin length. The effect of the residual stress induced by the bushing interference fit is also considered.

POSTPROCESSOR FOR AUTOMATIC MODE IDENTIFICATION FOR MSC/NASTRAN STRUCTURAL DYNAMIC SOLUTIONS WITH EMPHASIS ON AIRCRAFT FLUTTER APPLICATIONS (Acrobat 33K) #1498, 4 pgs.
Emil Suciu--Raytheon Systems Company
Joseph Buck--DeHavilland Inc.,Ontario

ABSTRACT: A practical procedure and postprocessor FORTRAN program which sums strain energies for an aircraft structure, elastic element by elastic element for each component as outputted by MSC/NASTRAN Solution 103 or Solutions 145 and 146 is described and an example is provided showing an output table of strain energies for a hybrid finite element model of a twin turboprop aircraft and comparison with a few plotted mode shapes. The application of the procedure to the .f06 output of one of the structural dynamic solutions results in automatic naming of the analytical modes of vibration, a powerful aid for the flutter analyst.

PREDICTION OF BREAK-OUT PATTERNS FOR AIRCRAFT CANOPIES FRAGILIZED MECHANICALLY OR WITH DETONATING CORD (Acrobat 160K) 1996, 7 pgs.
Rocky Richard Arnold--Leapfrog Technologies, Incorporated
Patrick S. Collins--Leapfrog Technologies, Incorporated

TURBINE ROTOR BURST CONTAINMENT ANALYSIS USING MSC/DYTRAN AN ANALYTICAL APPROACH TO PREDICTING PRIMARY CONTAINMENT (Acrobat 768K) 1996, 14 pgs. Kelvin Y. Ng--Hamilton Standard
ABSTRACT: With the common use of turbo-fluid machinery in the aerospace industry, rotor burst containment is an important design requirement. More demanding weight reduction goals are pushing containment structures to the brink of containment efficiency. Design engineers at Hamilton Standard have been reliant on design similarities and empirical data, to predict containability. However, limitations in the current methodology make detailed predictions difficult, especially if the geometry is not based on a previous design. In some cases, the limitations in the empirical method can lead to many costly tests. With the use of MSC/DYTRAN, and the help of the MacNeal-Schwendler Corp., Hamilton Standard has been developing an analytical method to predict rotor burst containment. Preliminary case studies have shown that MSC/DYTRAN can handle the physics involved with turbine rotor containment. Using the analytical methodology, structural damage and material response are characterized from the physics. Therefore, the prediction is independent of similar designs.
A VULNERABILITY MAP OF A COMMERCIAL AIRCRAFT (Acrobat 1.5MB) 1996, 19 pgs. Y. I. Moon--Wright Patterson AFB G. Bharatram--Wright Patterson AFB Capt. S. A. Schimmels--Wright Patterson AFB Dr. V. B. Venkayya--Wright Patterson AFB ABSTRACT: A method of developing a vulnerability map of a commercial aircraft is presented using MSC/DYTRAN and MSC/NASTRAN. The intent of the map is to establish the vulnerability of every point in the cargo hold where a bomb can explode. One might interpret each point in the cargo bay as having four dimensions. Three are spatial coordinates and the fourth is the maximum size of the bomb the structure can withstand without catastrophic failure. The vulnerability of the aircraft is examined from two distinct failure scenarios. The first is the response immediately after the bomb explosion. The second is the subsequent flight to the nearest airport for safe landing. The immediate response analysis is determined with MSC/DYTRAN and the post explosion analysis is made by MSC/NASTRAN. A complete vulnerability map requires many failure scenarios and a large number of MSC/DYTRAN and MSC/NASTRAN analyses. Six points in the cargo hold were critically examined to demonstrate the concept.

Analysis Methods

COUPLING OF MSC/NASTRAN AND BEM STRUCTURAL MATRICES (Acrobat 702K) #0493, 15 pgs.
M. J. MeNamee -- United Technologies Corporation
K. L. Leung -- United Technologies Corporation
P. B. Zavareh -- United Technologies Corporation

EXACT CALCULATION OF MINIMUM MARGIN OF SAFETY FOR FREQUENCY RESPONSE ANALYSIS STRESS RESULTS USING YIELDING OR FAILURE THEORIES (Acrobat 465K) #0593, 10 pgs.
Françis Charron -- Université de Sherbrooke
MSC/NASTRAN SHELL AND SOLID ELEMENT MESH REQUIREMENTS IN THE VICINITY OF A CIRCULAR HOLE STRESS CONCENTRATION (Acrobat 1.04MB) #0393, 18 pgs.
Robert P. Thacker, Jr. -- Boeing Computer Support Services
PARALLEL PROCESSING IN MSC/NASTRAN (Acrobat 500K) #0293, 11 pgs.
Dr. Louis Komzsik -- The MacNeal-Schwendler Corporation

Applications

THE COMBINATION OF MECHANICAL SYSTEM SIMULATION AND FINITE ELEMENT ANALYSIS SOFTWARE TO MODEL STRUCTURAL FAILURE IN AN AIRCRAFT ACCIDENT INVESTIGATION(Acrobat 943 K) #2699, 15 pgs.
Greg Savoni--Boeing Long Beach
J. McConville-- Mechanical Dynamics

ABSTRACT: The MSC/NASTRAN finite element analysis (FEA) code is used in conjunction with the ADAMS mechanical system simulation (MSS) program to simulate the structural behavior of the airframe of a commercial aircraft maneuvered beyond its
design limits during a landing. FEA-generated linear elastic structures are subjected
to non-linear boundary conditions in the MSS analysis to simulate the initial
structural failure of the airframe. The analysis results are compared with crash site
evidence and subsequent, independent engineering analysis.

COMPUTATION OF STRESS INTENSITY FACTORS USING MSC/PROBE VERSION 5 (Acrobat 1.16MB) #7693, 20 pgs.
John E. Schiermeier -- The MacNeal-Schwendler Corporation

ABSTRACT: In fracture mechanics, the stress intensity factor is used to determine whether a crack will run, possibly causing catastrophic failure or arrest. Typically, this value can be computed from the stress or displacement fields around the crack tip, either by hand or by numerical methods, and then compared with empirical data.

MSC/PROBE-PLANAR has long had two methods of computing Mode l and II stress intensity factors which take advantage of the p-version, the contour integral and cutoff function methods, as well as the standard energy release rate. In Version 5, MSC/PROBE-SOLID has incorporated singularity elements to model exactly the displacement field for a closed crack, and the crack-opening displacement (COD) method to automatically compute Mode I, II, and III stress intensity factors. Combined with the automatic p-adaptivity, accurate and reliable factors may be computed for fully three-dimensional problems in an efficient manner.

This paper provides an explanation of the stress intensity factors and the methods used to compute them. Sample problems are run, using MSC/XL V3B as the pre- and postprocessor, and the computed stress intensity factors are compared with theoretical results where available.

DESIGN AND ANALYSIS OF CORIOLIS MASS FLOWMETERS USING MSC/NASTRAN (Acrobat 833K) #5493, 17 pgs.
C. P. Stack -- Micro Motion, Inc.
T. J. Cunningham -- Micro Motion, Inc.

ABSTRACT: A Coriolis mass flowmeter measures mass flow directly by vibrating a fluid-conveying pipe at resonance. Design of these meters was facilitated by solving the equations of motion via the finite element method. A complex eigenvalue analysis (SOL107) was necessary due to the presence of the Coriolis force terms in the damping matrix. Performance parameters of the meter can be predicted from the complex eigenvectors and were found to match experimentally determined values to within five percent.

Since vibration occurs during Coriolis meter operation, low stress designs must be used to preclude fatigue failure. This analysis was also performed using MSC/NASTRAN.

DETERMINING TUBE STRESS FROM CBEND ELEMENT FORCES AND MOMENTS (Acrobat 740K) #6493, 15 pgs.
Raymond N. Frick, Ph.D., P.E. -- Pratt & Whitney

ABSTRACT: MSC/NASTRAN is used extensively in the design of external tubing for turbo-fan aircraft engines at Pratt & Whitney. It accurately calculates the stress of tubes under pressure, thermal, and case displacements and also natural frequencies. Many of the external tubes are small diameter (under 3/4 inch) and are part of a complex tube system. The most effective element type for these tubes is a "beam" element such as the CBEND. A complex small diameter tube system modeled with CBEND elements is very efficient compared with the same system modeled with CQUAD4 plate elements. However, while the MSC/NASTRAN CBEND element uses the ASME Code equations to account for the ovalization of the tube in the bends, the stress output is not complete. The in-plane and out-of-plane bending moments are not combined while the torque stress and the hoop stress are ignored. Therefore, the correct principal stresses are not determined. Pratt & Whitney developed a CBEND post-processor which uses the ASME Code equations to determine the complete stress field from the MSC/NASTRAN calculated forces and moments. This paper presents the ASME Code equations used by the CBEND post-processor and compares the results to equivalent plate models. Based upon these comparisons, the use of the MSC/NASTRAN CBEND element has been implemented in the design of small diameter tubes.

THE DEVELOPMENT AND USE OF A MATERIALS DATABASE FOR PRODUCT DESIGN AND COMPONENT LIFING.(Acrobat 228K) #0199, 13 pgs.
Barry J Piearcey, Chris K Bullough, Martin Hughes and Steven J Moss--ALSTOM Energy Technology Centre

ABSTRACT:Tremendous progress has been achieved in the application of finite element analysis techniques for the modelling of the behaviour of components and structures but the success of application is often limited by the availability of appropriate materials design data. Even when data are available, usually from published sources, some of the supporting metadata is often missing and validation of the design data is not possible. Even well planned characterisation of materials properties through well executed testing programmes lose their value as details of the test parameters and materials are inadequately recorded; and ad-hoc statistical assessment methods obscure the true minimum properties of a material.

This paper describes the development and structure of an MSC/MVISION materials database which is designed to store test and design data. Metadata has been defined to describe each material product and property precisely, standard methods of data analysis provide validated design data and each datum is allotted a quality value. Examples are included which illustrate how the data are used for statistical process control, thermal analysis, stress analysis and the prediction of component life using a continuum damage approach.

The similarity in the technologies used for these disparate activities is counterbalanced by the lack of material property data of sufficient quality. This situation is recognised world-wide as is the inability of any single company to justify adequate resource to correct it. It is concluded that the high cost of producing high quality material product data by independent testing calls for more facilities for the assessment, reporting and exchange of data within MSC/MVISION and highlights the need to agree an international schema and glossary of terms for data exchange.

DYNAMIC MODELING AND ANALYSIS OF SPINNING POLYGON ASSEMBLIES USING MSC/NASTRAN (Acrobat 438K) #6693, 7 pgs.
Bill Nowak -- Xerox Corporation
Courtney James -- Xerox Corporation

ABSTRACT: This paper describes the application of MSC/NASTRAN to calculate the dynamic response of a spinning polygon, motor, and motor housing used in xerographic printers. Initially, different levels of model sophistication were evaluated showing convergence to a representative model. Using the converged model, the dynamic response of the polygon mirror was evaluated from the effects of base excitation. Frequency correlation in the 0 to 1000 hertz range was demonstrated to be better than 10% when compared to a dynamic modal test. Mechanical gain correlation at the fundamental rotor resonance was of the same order as the modal test with amplitude variations attributed to the assumed damping of the model and differences between empirical and analytical response locations. Conclusions and recommendations on future work are also cited.

ELECTRO-MECHANICAL RESPONSE SIMULATION OF ELECTROSTATIC VOLTMETERS USING MSC/NASTRAN (Acrobat 469K) #6593, 8 pgs.
Bill Nowak -- Xerox Corporation

ABSTRACT: This paper describes the application of MSC/NASTRAN to simulate the electro-mechanical behavior of in situ electrostatic voltmeters. These "tuning fork" style transducers are used to continuously monitor photoconductor voltage during xerographic copier and printer operation. Voltmeter theory of operation is discussed, and finite element model development is detailed showing a 6% correlation of natural frequency with empirical results. From an existence proof, model boundary conditions were adjusted to show correct voltmeter dynamic response. Based on this empirical behavior, structural design modifications were made to the model until similar dynamic response was analytically achieved. These modifications were then applied to the hardware and correct performance was empirically verified. Conclusions and recommendations on future work are also cited.

EXTENDED DETAILED FINITE ELEMENT ANALYSIS OF A 9.6 METRE AUTOGENOUS SAG MILL (Acrobat 1.52MB) #5393, 25 pgs.
John Hadaway -- ANI PRODUCTS
Eric Hecht -- COMPUMOD Pty. Ltd.

ABSTRACT: Finite element analysis is becoming an integral part of the design and manufacturing process of heavy engineering machinery for the mining industry in Australia. The Grinding Mill division of Australian National Industries (ANI) which is the division of ANI responsible for design, manufacture and supply of ore grinding mills to mines throughout Australia and overseas have been using the MSC/NASTRAN finite element analysis code extensively in all phases in the supply of their mills.

The finite element analyses of a 9600 mm diameter (5640 mm length) Autogenous Grinding Mill is used to describe how today's available technology is being used by one company to design and manufacture machinery for the mining industry.

FINITE ELEMENT ANALYSIS OF THE RISER COLUMN CHAINTABLE AND CHAINHAWSE STRUCTURES FOR A FLOATING PRODUCTION STORAGE AND OFFLOADI NG FACILITY USING MSC/NASTRAN (Acrobat 1.92MB) #4393, 17 pgs.
D. J. Twine -- BHP Engineering Pty. Ltd. Dr. S. Loganathan -- BHP Engineering Pty Ltd

ABSTRACT: An overview is given of a recently completed finite element stress analysis of the Riser Column Chaintable and Chainhawse Structures for an offshore Floating Production Storage and Offloading (FPSO) oil and gas facility.

The project involved finite element modeling of a symmetric half model of the chaintable and analysis of the model under a series of Unit Load Cases and Load Combinations. The primary objective of the analysis was to quantify stress levels and stress combinations throughout the structure to enable strength and fatigue capacity of the chaintable and chainhawse structures to be confirmed.

The model involved approximately 60,000 DOF and analysis was carried out using a CRAY-YMP Supercomputer.

The paper will present a summary description of the problem and objectives of the analysis, finite element discretisation of the structure, analysis approach, and quality assurance checking procedures applied to verify the results.

FINITE ELEMENT ANALYSIS (FEA) OF THE STATIC AND DYNAMIC RESPONSE OF THE SHEET MOLD COMPOUNDING (SMC) STRUCTURE USING THE ENHANCED MODELING TECHNIQUE OF THE ADHESIVE JOINING REGION (Acrobat 589K) #6393, 20 pgs.
Joon B. Park -- Automated Analysis Corporation
Randal H. Visintainer -- Ford Motor Company

ABSTRACT: An FEA study was conducted to examine the static and dynamic response of an SMC structure fabricated by adhesive joining method using MSC/NASTRAN. The appropriate modeling of the adhesive joining region is essential in precise FEA predictions of static and dynamic response of the SMC structure presented. An enhanced modeling technique for the adhesive joining region is presented in this paper. A composite mechanics approach was used to define the mechanical property of finite elements along adhesive joining region. Static and dynamic predictions of the enhanced modeling technique were compared with predictions of the conventional linkage modeling method in structure analysis.

A FINITE ELEMENT METHODOLOGY FOR PREDICTING RELATIVE MOTION OF AVIONICS MODULE CONNECTOR CONTACTS (Acrobat 99K) #4193, 15 pgs.
Mark H. Morton -- Lockheed Aeronautical Systems Company
David S. Layton -- Lockheed Aeronautical Systems Company

ABSTRACT

MANEUVERING OF THE SPACE STATION/ORBITER DURING AN ASSEMBLY FLIGHT (Acrobat 1.54MB) #3093, 20 pgs.
Paul A. Cooper -- NASA Langley Research Center
Alan E Stockwell -- Lockheed Engineering & Sciences Company
Shih-Chin Wu -- Lockheed Engineering & Sciences Company

ABSTRACT: A large-angle, multi-body, dynamic modeling capability was developed to help validate numerical simulations of the dynamic motion and control forces which occur while berthing Space Station Freedom to the Shuttle Orbiter during early assembly flights. The paper describes the dynamics and control of the station, the attached Shuttle Remote Manipulator System, and the Orbiter during a maneuver from a gravity-gradient attitude to a torque equilibrium attitude using the station reaction control jets. The influence of the elastic behavior of the station and of the remote manipulator system on the attitude control of the station/Orbiter system during the maneuver is investigated. The flexibility of the station and the arm had only a minor influence on the attitude control of the system during the maneuver.

MODELING AND ANALYSIS OF 4-STEP 3-D CARTESIAN BRAIDED COMPOSITES (Acrobat 1.04MB) #7593, 20 pgs.
Soheil Mohajerjasbi -- Boeing Defense & Space Group

ABSTRACT

In contrast with these findings, some of the present analytical models consider a "unit cell" as a repeat unit for the braided composite, and attempt to model the mechanical behavior of the composite from the properties of this unit cell. This unit cell is in the form of a parallelpiped with yarns connecting between the opposite corners along the body diagonals.

In this paper, a finite element based method is proposed for modeling the structure of the 3-D braided composite, and determining the elastic constants and coefficients of thermal expansion. MSC/NASTRAN is used in modeling the thermoelastic properties of the composite. Estimates of elastic constants and coefficients of thermal expansion are developed as a function of "interior braiding angle".

Among advantages of this technique are simplicity, and the ability to model and study the response of complex shapes subject to complex loads applied at the boundary.

MSC/FLIGHT LOADS AND DYNAMICS-VERSION 1(Acrobat 358 K) #0299, 10 pgs.
Greg Sikes and Douglas J. Neill--The MacNeal-Schwendler Corporation

ABSTRACT: MSC has been actively developing solutions to the challenges faced by our customers inthe area of external loads and aerodynamic response. Through strategic partnerships with the world's leading civilian and military air vehicle manufactures, MSC has developed an in-depth understanding of our customers' needs. These efforts have lead to the development of an integrated, process-driven external loads and dynamics system called MSC/FlightLoads and Dynamics.

MSC/FlightLoads and Dynamics Version 1 supports static aeroelasticity (steady state external loads). This paper will present the current state of the technology within MSC/FlightLoads and Dynamics Version 1.

THE NEW EXTERNAL SUPERELEMENTS IN MSC/NASTRAN AND A DMAP ALTER TO CREATE AND USE OTM
(Acrobat 325 K) #2499, 17 pgs.
Ted Rose--The MacNeal-Schwendler Corporation

ABSTRACT: It often seems to be several years after the introduction of a new feature before it gains recognition among the user community. This paper is intended to provide an introduction to the new external superelement features introduced in V69 and also provide a DMAP alter which allows the creation and usage of OTM for them, allowing the creation and usage of "deliverable" models.

N-250 WINDSHIELD FINITE ELEMENT MODEL (Acrobat 338K) #7893, 10 pgs.
Masduki Suwandi -- Nusantara Aircraft Industry Ltd.
Kurnia Witono -- Nusantara Aircraft Industry Ltd.
Nurdin -- Nusantara Aircraft Industry Ltd.

ABSTRACT: In analyzing the windshield of N-250, - Indonesian / IPTN's latest aircraft product - one major issue is how to model the windshield glass panel and the distribution of the load to its mounting structure. This paper concentrates on this issue.

NON-LINEAR ANALYSIS OF A PROPELLER BLADE RETENTION SYSTEM (Acrobat 480K) #3293, 6 pgs.
John C. Lambert -- United Technologies Corporation

ABSTRACT

RADIATION HEAT TRANSFER WITH SPECTRAL SURFACE BEHAVIOR (Acrobat 199K) #5593, 7 pgs.
Mike Chainyk -- The MacNeal-Schwendler Corporation

ABSTRACT: Prior to Version 68, MSC/NASTRAN radiation exchange was restricted to ideal black/grey opaque surfaces exhibiting diffuse emission, absorption, and reflection characteristics. Most real surface behavior is considerably more complicated due to varying degrees of specular, spectral, and temperature dependent properties, as well as radiant transmission. Generalized numerical treatment of all of these phenomena simultaneously is beyond the scope of the current Version 68 effort, however, most materials in a practical engineering sense may be characterized by one or two dominant surface conditions. In particular, most solar collection device materials as well as high temperature metals can be satisfactorily described in terms of their spectral and temperature dependent surface properties. This problem class is addressed with a method known as the radiation energy-band approximation.

A REFINED METHOD FOR LIVE-LOAD DISTRIBUTION PREDICTION OF BRIDGES AND COMPARATIVE STUDY (Acrobat 678K) #5293, 20 pgs.
Yohchia Chen, Ph.D., P.E. -- The Pennsylvania State University

ABSTRACT: A refined analysis method is proposed for predicting the distribution of vehicle live loads on bridge girders. An effective and efficient iteration scheme is used to solve the nonlinear equations. Two representative bridge systems are investigated. The obtained results from the proposed method are compared to experimental data and those obtained from other analysis methods. The prediction method for live-load distribution implemented in the current bridge design code is carefully examined. The paper concludes with a number of actual bridge examples and recommendations.

RESPONSE OF PROTECTIVE STRUCTURES TO INTERNAL EXPLOSIONS WITH BLAST VENTING (Acrobat 1.77MB) #4293, 22 pgs.
Y. Kivity -- The MacNeal-Schwendler Company
C. Florie -- The MacNeal-Schwendler Company
H. Lenselink -- The MacNeal-Schwendler Company

ABSTRACT

STRUCTURAL ANALYSIS OF AN 85 FT. FREE STANDING TOWER (Acrobat 946K) #3393, 23 pgs.
Paul F. Martin -- Massachusetts Institute of Technology

ABSTRACT

THERMOMECHANICAL FINITE ELEMENT ANALYSIS OF STIFFENED, UNSYMMETRIC COMPOSITE PANELS WITH TWO DIMENSIONAL MODELS (Acrobat 1.53MB) #3193, 18 pgs.
Craig S. Collier, P.E. -- Lockheed Engineering and Sciences Co., NASA Langley Research Center
Kevin A. Spoth -- Lockheed Engineering and Sciences Co., NASA Langley Research Center
Glenn C. Grassi -- The MacNeal-Schwendler Corporation

ABSTRACT

USING MSC/MVISION TO COMPARE MSC/NASTRAN RESULTS WITH FLIGHT TEST DATA
(Acrobat 488K) #2599, 20 pgs.
Kirsten Husak--Raytheon Systems

ABSTRACT:At Raytheon Systems Company in Waco, Texas, a MSC/MVISION database has been developed which allows the comparison of flight test data with MSC/NASTRAN results output. A model can be opened in MSC/PATRAN, and strain gauge results generated during a test flight viewed directly on the model. The MSC/NASTRAN strain output can be applied to the model and contrasted with test flight strains in the MSC/PATRAN graphical user interface. If the results are reconciled within a predetermined degree of tolerance, it will then be assumed that the model is accurate. A model predicting the behavior of the aircraft after it has been modified can then be assumed to be accurate also. After the aircraft has been modified, more flight test data will be collected, which can then be compared with the post-modification
predictions to aid in support of FAA certification of the modified aircraft. MSC/MVISION will provide a user-transparent interface between MSC/PATRAN and the raw flight test data, allowing engineers to view the accuracy of their models with real-time strain measurements within the MSC/PATRAN graphical environment. Because Raytheon Waco specializes in aircraft modifications, the concentration in this project has been on the comparison of flight test data with airframe finite element models, but the application of this methodology for comparison of strains with models can be used in any industry which employs modeling and testing procedures.

VIRTUAL MASS OF FLUID IN EGG-SHAPED DIGESTERS (Acrobat 316 K) #7793, 9 pgs.
Atis A. Liepins -- Simpson Gumpertz & Heger Inc.
Hamid Nazemi -- Simpson Gumpertz & Heger Inc.

ABSTRACT

Automobile Applications

ANALYSIS OF FLEXIBLE ROTATING CRANKSHAFT WITH FLEXIBLE ENGINE BLOCK USING MSC/NASTRAN AND DADS(Acrobat 787K) #3595, 15 pgs. Lee S. Mayer--Computer Aided Design Incorporated Hans Zeischka--Computer Aided Design Incorporated NV Frank Maessen--Computer Aided Design Incorporated NV Marc Scherens--Computer Aided Design Incorporated NV

ABSTRACT

ANALYTICAL PREDICTION OF LEAF SPRING BUSHING LOADS USING MSC/NASTRAN AND MDI/ADAMS (Acrobat 2MB) 1996, 16 pgs. Shahriar Tavakkoli--Ford Motor Company Farhang Aslani--Ford Motor Company David S. Rohweder--Ford Motor Company Satyendra Savanur--Automated Analysis Corporation

ABSTRACT

THE APPLICATION OF FEM-EMA CORRELATION AND VALIDATION TECHNIQUES ON A BODY-IN-WHITE (Acrobat 1.05MB) #0693, 18 pgs. Marc Brughmans -- LMS International Kevin Blauwkamp -- GM - Saturn Corporation Jan Leuridan -- LMS International

ABSTRACT

APPLICATION OF A FRF BASED MODEL UPDATING TECHNIQUE FOR THE VALIDATION OF FINITE ELEMENT MODELS OF COMPONENTS OF THE AUTOMOTIVE INDUSTRY (Acrobat 1.77MB) #0795, 20 pgs. Stefan Lammens--LMS International Marc Brughmans--LMS International Jan Leuridan--LMS International Paul Sas-- Katholieke Universiteit Leuven

ABSTRACT

BACK LOAD CALCULATION: A METHOD OF MEASURING COMPONENT LOADS WITHOUT LOAD CELLS (Acrobat 1.6MB) 1996, 21 pgs. P. R. Perumalswami--Ford Motor Company A. J. Page--Ford Motor Company

ABSTRACT

This technique is applied to an automobile suspension component. Results show excellent correlation of back calculated load with the actual load. Also a conventionally instrumented (with designed load cell) component is used for comparison. The proposed method consistently showed considerable improvement over the conventional method.

BUMPER DESIGN USING COMPUTER SIMULATION (Acrobat 387K) #1093, 12 pgs.
Hwa-Won Lee -- SsangYong Motor Company
Sung-Kuk Jang -- SsangYong Motor Company

ABSTRACT

This paper attempts to present such a design and analysis method, using relatively simple beam model and fine meshed shell model. The analysis has been performed for center - center pendulum and barrier hits of a bumper system of XENOY™ 1102 newly developed by GEP (General Electric Plastics US) under the process of injection molding.

Finally, the results predicted from finite element method are compared with those of experimental tests to evaluate the analysis procedure.

THE CONTRIBUTION OF PASSENGER SAFETY MEASURES TO THE STRUCTURAL PERFORMANCE IN SPORTS RACING CARS (Acrobat 1.1MB) 1996, 19 pgs. Mark Roots--Cranfield University Jason Brown--Cranfield University Neil Anderson--Cranfield University Thomas Wanke--Cranfield University Marco Gadola--Cranfield University ABSTRACT: This report deals with the modelling of an Automotive Chassis using MSC/NASTRAN. The torsion stiffeness of the chassis was able to be increased by 500% over the initial configuration by judicious design. In an effort to allocate more science to the problem of roll cage design it was proposed that nonlinear finite element analysis using MSC/NASTRAN would give a good indication of the true load carrying capacity and deflection under load of the roll cage/frame. The analysis carried out was verified by the test programmme on a full scale chassis. This analysis gave results within an accepatable 10% of the test results despite the simplifying assumptions. This application of MSC/NASTRAN is new as most small automotive manufacturers rely on past experience for their development. This works well for evolutionary design but not for major structural modifications as were carried out. This report highlights the value of MSC/NASTRAN in this application. DEVELOPMENT OF A METHODOLOGY TO PREDICT THE ROAD NOISE PERFORMANCE CHARACTERISTICS (Acrobat 329K) #0993, 8 pgs. Mark P. Voutyras -- Chrysler Corporation William F. Resh -- Chrysler Corporation Kevin R. Thomson -- Chrysler Corporation ABSTRACT: This paper describes the development of a methodology for predicting the road noise performance characteristics of an automotive vehicle system. An MSC/NASTRAN finite element model of a complete suspension system was constructed and analyzed for dynamic response. In addition, a customized system simulation software package, GRADAM, was developed for combining the FEA and experimental results in order to assess vehicle structural sensitivity to noise and also to study the effect of suspension design modifications on the interior noise levels. In the model development stage, the FEM modal and frequency response results for all the relevant suspension components were validated by comparing with the corresponding experimental measurements. The interior noise levels were then obtained through the system simulation software. This customized software combines the MSC/NASTRAN force output at suspension-to-body attachment points with the corresponding pressure/force (P/F) experimental data in order to predict the interior noise levels. The methodology developed herein permits the noise pressure levels to be determined for desired frequency domains. Furthermore, this methodology allows design engineers to answer "what if" questions in order to evaluate the effect of suspension design changes on the interior noise levels. It is anticipated that the methodology presented herein will be instrumental in optimizing the noise and vibration (NVH) characteristics of future car lines. DEVELOPMENT OF A NONLINEAR FREQUENCY RESPONSE PROGRAM FOR SIMULATING VEHICLE RIDE COMFORT (Acrobat 491K) #3795, 9 pgs. Keuchiro Tsutsui-- ESTECH Corporation Ray Nogami--ESTECH Corporation John L. Breti, Ph.D.-- Structural Dynamics Research Corp.

ABSTRACT

FINITE ELEMENT ANALYSIS OF AUTOMOBILE CRASH SENSORS FOR AIRBAG SYSTEMS (Acrobat 288K) 1996, 9 pgs. Christopher A. Leger--Breed Technologies, Inc Claude A. Bryant--Breed Technologies, Inc ABSTRACT: Automobile spring bias crash sensor design time can be significantly reduced by using finite element analysis as a predictive engineering tool. The sensors consist of a ball and springs cased in a plastic housing. Two important factors in the design of crash sensors are the force-displacement response of the sensor and stresses in the sensor springs. In the past, sensors were designed by building and testing prototype hardware until the force-displacement requirements were met. Prototype springs need to be designed well below the elastic limit of the material. Using finite element analysis, sensors can be designed to meet force-displacement requirements with acceptable stress levels. The analysis procedure discussed in this paper has demonstrated the ability to eliminate months of prototyping effort. MSC/ABAQUS has been used to analyze and design airbag crash sensors. The analysis was geometrically nonlinear due to the large deflections of the springs and the contact between the ball and springs. Bezier 3-D rigid surface elements along with rigid surface interface (IRS) elements were used to model ball-to-spring contact. Slideline elements were used with parallel slideline interface (ISL) elements for spring-to-spring contact. Finite element analysis results for the force-displacement response of the sensor were in excellent agreement with experimental results.
FLEXIBLE VEHICLE SIMULATION OR MODELING VEHICLE SUSPENSION COMPLIANCE AT FORD MOTOR CO. USING A COUPLING OF ADAMS AND MSC/NASTRAN (Acrobat 712K) #0793, 12 pgs. Shawn P. McGuan -- Mechanical Dynamics, Inc. Steve Pintar -- Ford Motor Company ABSTRACT: The Core Development Technology group at the Ford Motor Company is actively involved in correlating analytical (ADAMS) vehicle models with objective (telemetric) data from instrumented vehicles. In the past, vehicle compliances were introduced into the ADAMS model by using the ADAMS elements; TIREs, nonlinear BUSHINGs and BEAMs. With the advent of ADAMS/FEA^TM, a data translator which provides a two-way interface between ADAMS and MSC/NASTRAN, vehicle models may now include the effects of geometrically complex component stiffness and total body compliance in the ADAMS full vehicle simulation. This paper examines the effects of these added compliances on an ADAMS vehicle model by comparing the dynamic toe and camber angles of a vehicle with rigid upper and lower control arms to a vehicle with flexible upper and lower control arms built from MSC/NASTRAN data. The results demonstrate that complex problems can be very efficiently modeled and simulated by combining finite element analysis (MSC/NASTRAN) and mechanical system simulation (ADAMS) technologies. FRICTION INDUCED VIBRATION (Acrobat 732K) #3695, 18 pgs. Wayne V Nack--General Motors Corporation Arun M Joshi--General Motors Corporation

ABSTRACT

MODAL TEST ON THE PININFARINA CONCEPT CAR BODY, "ETHOS 1" (Acrobat 785K) #0595, 15 pgs. ir M. Brughmans--LMS International ir F. Lembregts, PhD--LMS International ir F. Furini, PhD--Industrie Pininfarina
NONLINEAR DYNAMICS OF BRAKE SQUEAL (Acrobat 128K)1996, 20 pgs. M. L. Chargin--NASA Ames Research Center L. W. Dunne--CDH GmbH D. N. Herting--CDH GmbH ABSTRACT: An efficient procedure for the analysis of brake squeal using MSC/NASTRAN models is described. A unique nonlinear method accounts for both superelement modes and surface friction data. The motions at the pad/rotor interface are described by small velocities and pressures relative to the steady-state condition. Both Transient Analysis and Complex Eigenvalues are provided analysis of brake systems.
A STUDY ON IDLE VIBRATION ANALYSIS TECHNIQUE USING TOTAL VEHICLE MODEL (Acrobat 322K) #0695, 7 pgs. H.B. Park--Hyundai Motor Company J.K. Suh--Hyundai Motor Company H.G. Cho--Hyundai Motor Company G.S. Jung--Hyundai Motor Company

ABSTRACT:

TRUCK INTERIOR NOISE PREDICTION BY FEM AND BEM (Acrobat 3.8MB)1996, 9 pgs. Amiya R. Mohanty--Ford Motor Company Barry D. St. Pierre--Ford Motor Company P. Suruli-Narayanasami--Ford Motor Company

ABSTRACT

USING MSC/NASTRAN FOR THE CORRELATION OF EXPERIMENTAL MODAL MODELS FOR AUTOMOTIVE POWERTRAIN STRUCTURES (Acrobat 879K) #0893, 16 pgs.
L.D. Isley -- Borg Warner Automotive
W.R. Kelley -- Borg Warner Automotive

ABSTRACT: This paper describes the methods and analyses used in the correlation of experimentally determined modal models to analytical solutions. The paper illustrates the significant benefits of Component Mode Synthesis and Design Sensitivity Analysis options available in MSC/NASTRAN in the correlation process. Neutral File Interface programs and remote orthogonality calculation methods that simplify the communication between the FEA solution and the laboratory results are also discussed. Three (3) specific experimental procedures formulated the basis for the paper. The first, a simple free-free beam case is presented. The second and third are examples of more complex automotive transmission assemblies with special boundary condition issues and internal component influences. Specific recommendations for improving correlation potential both in laboratory test methods and in the finite element modeling task have been provided.

CAE Processes

ANALYSIS AND EVALUATION OF MINIVAN BODY STRUCTURE FINITE ELEMENT METHODS (NOT PRESENTED) (Acrobat 1.3MB) #4099, 15 pgs.
Jin ya-min--Harbin Hafei Motor Co., Ltd., China

ABSTRACT: The paper describes the application of MSC product in Harbin Hafei Motor Co., Ltd and then describes how the finite element methods can be used for analysis and evaluation of minivan body structure. Including static, dynamic, fatigue, crashworthiness analysis, optimization and sensitivity and so on. In this paper, Author use MSC-NASTRAN calculate the strength and stiffness in both bending and torsion loadcase. Summarized the strength and stiffness evaluation standards for minivan. And then done the normal model analysis in order to consider the influence of tyre unbalance and engine idle excite. The calculations and analysis were verified by test.

APPLICATION OF FEM ANALYSIS IN ENGINE DEVELOPMENT (Acrobat 780K) #3299, 13 pgs.
Naohisa Mamiya--Nissan Motor Co. Ltd. Japan

ABSTRACT: To address environmental issues and at the same time supply products that are attractive and a high quality to the market, Nissan is adopting predictive development based on the latest computer-aided engineering (CAE) technology in engine development.
To achieve efficiency in the development from an early stage of engine development to the making of a highly complete prototype and finally to the mass production stage, a tool for advance evaluation of engine performance, function, and reliability is needed. The use of computer simulation technology has become indispensable for that purpose.
Here, we briefly introduce the incorporation of CAE technology into actual engine design work and the current state of affairs, presenting some specific examples that focus on finite element method (FEM) analysis.

APPLICATION OF FEM-TOOLS IN THE ENGINE DEVELOPMENT PROCESS (Acrobat 18MB) #2399, 10 pgs.
H. Petrin and B. Wiesler--AVL List GmbH, Austria

ABSTRACT: The requirements for the development of a new engine are the considerable reduction of development time and costs as well as the reduction of production costs, considering a higher number of product variants and higher product quality, are boundary conditions for the actual engine development. To achieve this goal the automotive industry worldwide tries to organize their development activities more efficiently in "Development Processes" and searches for optimization potential.
AVL is working together with a various number of automotive companies all over the world trying to adjust its services (e.g. FEM-calculations) for best fitting into the "Engine Development Process" of each of the customers. AVL also takes over to some extend working parts of the customer's processes and is even asked to optimize the processes.
The paper discusses the effective use of FEM-tools in engine development processes, as derived in co-operation with many automotive companies and in-house engine development, under special consideration of latest tools for mesh generation and calculation performance.
The optimized correlation between the different calculation tasks and the development process, the right starting time and extend (time frame) for the use of the simulation and the application of fast and validated simulation software assures reliable results in time.
The proper application of the FEM-tools in the design phase and the best support during the testing phase reduces the risk and the testing effort in the prototype and pre-production phase and is the essential basis for the reduction of development time and costs.

AUTOMATIC SHAPE OPTIMIZATIONS OF ELASTOMERIC PRODUCTS (Acrobat 1.5MB) #2199, 15 pgs.
M. Friedrich and J. Baltes--Freudenberg Forschungsdienste KG
M. Schütz and H. Gärtner--Freudenberg Dichtungs- und Schwingungstechnik KG

ABSTRACT: In increasing international competition, technologically oriented companies can only survive, if they can also provide cost efficient products as well as a high technological innovation strength. Therefore, in modern development philosophies, like "Simultaneous Engineering" the calculations engineer is more and more consulted in the conceptional phase of product development. Consequently, it is compellingly necessary in an effective procedure that all tools and data be placed at everyone's disposal. This way, everyone is better able to assist the conceptional design of new products as well as to make detailed improvements on already existing designs. Therefore, efficiently implemented optimisation algorithms complement the proven discrete calculation procedures (FEM, BEM) of mechanically loaded structures .
In structural mechanics, there are three levels of optimisation:
•Topology
•Shape
•Sizing
Topology optimisation, like that from Bendsoe and Kikuchi , has the capability to support the design level. Presently, for the industrial application of topology optimisation only a small number of commercial codes is available. The shape optimisation has been used for industrial applications for some time, but it is used to handle almost exclusively linear problem sets. The sizing optimisation is offered from almost every large FEM-package. It is industrially applied mainly for complex beam and shell structures.
While not as complex as the topology optimisation is, shape optimisation will be strengthened and widely applied in industry in the near future. This results from the necessity to apply a detail shape optimisation to already topology optimized components, too. In this paper the special case of shape optimisation for handling models with hyperelastic materials is focussed.

BONDING AREA OPTIMIZATION FOR REDUCING WAVEFRONT ERROR IN OPTICAL ELEMENTS (Acrobat 683K) #1299, 15 pgs.
Yair Soffair--Electro-Optics Industries Ltd., Israel

ABSTRACT: The objective of this analysis is to recommend an optimal bonding configuration for a large Dove prism for minimal wavefront error, maintaining bond strength while subjected to severe environmental conditions.

DRIVING YOUR DESIGNS WITH MSC.SOFTWARE'S AUTOMOTIVE SOLUTIONS (Acrobat 455K) #0199, 5 pgs.
Ken Blakely--MSC.Software Corporation

ABSTRACT: The automotive industry accounts for nearly 30% of MSC.Software's business. It is truly global in nature for us, with our business being spread equally around each of the world regions (Americas, Europe, and Asia-Pacific). "Automotive" includes cars, trucks, SUVs, buses, motorcycles, tires, engines, and components, from OEMs to third-tier suppliers.
This paper briefly describes MSC.Software's automotive solutions. These are comprised of our core software, our automotive-specific software, and our automotive services. This paper provides a glimpse of things you will learn about in more detail during the Conference.

A FINITE ELEMENT VEHICLE ANALYSIS LIBRARY FOR COMMERCIAL VEHICLES (Acrobat 130K) #2799, 9 pgs.
Ir. J. Maasdam--DAF Trucks N.V.

ABSTRACT: MSC/NASTRAN is one of the general purpose finite element programs used at DAF Trucks N.V. Performing a finite element analysis of a commercial vehicle may be time consuming for two reasons. Firstly, many variations in vehicle specification exist, due to customer request. Secondly, the investigation of the static and dynamic behaviour of commercial vehicles often requires a full vehicle model. The resulting large numerical model has typically several hundred thousand degrees of freedom.
In order to perform the requested static and dynamic analysis on time, DAF Trucks N.V. applies component mode synthesis and automatically assembles a full vehicle model from a vehicle analysis library.
This paper addresses some aspects of the vehicle analysis library and shows examples of a full vehicle model used for static and dynamic analysis. The dynamic analysis example shows how frequency response functions, calculated with MSC/NASTRAN, are post-processed with the aid of a toolbox. This toolbox enables fast evaluation of e.g. ride comfort and load spectra for a variety of operating conditions. Furthermore, online sensitivity or optimisation studies are possible.

HIGH PERFORMANCE, PROCESS ORIENTED, WELD SPOT APPROACH (Acrobat 325K) #2599, 14 pgs.
Daniel Heiserer and Juergen Siela--BMW AG Muenchen
Mladen Chargin--CDH GmbH

ABSTRACT: Simulation of automotive vehicles has become a more important step in car development in the last few years. Rapid prototyping, which offers a close-to-market product, with less hardware, requires a fast and accurate computer simulation to guarantee a quality product.
Generation of body-in-white nite element models for full vehicle simulation of Linear Statics, Normal Modes, NVH, and Crash is one of the most critical items. This is due to the need to connect various body-in-white components which requires:
•a signicant amount of manpower because of difficult automation possibilities
•a "physically correct" representation of part-connectors such as weld spots, screws, etc., which cannot be easily automated and requires more manpower resulting in delays and a potentially large source of error
In the past, a number of methods were developed for joining these parts together, such as homogenous models and various other weld spot approaches. In the generation of FE-models, each part depended on its connected parts, which made it difficult to shorten the modeling process. Benefits of faster hardware, and some improvements in preprocessors, were diminished by the need for bigger models.
Despite the above improvements, a signi.cant amount of time was still required to generate FE models. CDH and BMW developed a spot welding approach, linchweld, which simultane- ously reduced the modeling time, invested manpower, and increased the quality of simulation (compared to test).
The program containing the linchweld approach is called CDH/SPOT.

INTEGRATION OF CFD AND THERMAL STRESS ANALYSIS FOR TURBOCHARGERS (Acrobat 650K) #3499, 7 pgs.
Mikio Obi, Nobuo Takei and Natsuko Matsuura--Ishikawajima-Harima Heavy Industries Co., Ltd., Japan

ABSTRACT: In the manufacturing industries, there is a trend lately to employ a new manufacturing method using 3D-CADs in the manufacturing process. The purpose of employing the new method is to cut the lead time of a new product and achieve the timely introduction of the product into the market when it meets customers' needs by solving manufacturing problems with 3D-CADS in the design phase. The real effects of introducing 3D-CADs can be realized by not only examining designs in three dimensions in the design phase, but also by converting entire development processes to be based on digital data by reflecting design model data in such production data as those for various analyses and mold production. We also have been changing development processes from drawing-based conventional processes to those based on digital data.

Our company develops such rotating machinery as turbochargers and turbo-compressors. Because they are fluid machinery with complex geometry consisting of many free form surfaces, many good results can be expected by employing 3D-based development. Further, because we produce products by partially altering the design of our standard specification products for general-purpose applications according to the customer's requirements, we can expect to improve design speed by establishing the new development processes mentioned about and by re-using existing data effectively. Generally, rotating machinery consists of many machine elements and some of them are put into such severe conditions as high-speed rotation under high temperature. Therefore, analysis is very important in the developing processes and it is fundamental to implement analysis procedures smoothly in the development processes. We analyzed the thermal stress of a turbine housing of turbocharger by transferring the results of temperature distribution analysis, which is based on the results of thermofluids analysis, to structural analysis. By comparing the flow of the analysis with the conventional analysis procedures, we will describe the effects and problems of the new procedures, which we encounter when applying them to design procedures.

INTEGRATION OF INNOVATIVE CAE METHODS IN CHASSIS ENGINEERING AT PORSCHE (Acrobat 163K) #1899, 11 pgs.
Harald Bähr--Porschestraße

ABSTRACT: The consistent application of CAE methods in Porsche's Chassis Engineering helps to clearly lower development times and costs while improving both quality and reliability.
This presentation describes the CAE-assisted development procedures used by Porsche in chassis engineering. It outlines the results obtained and the development activities planned for the future.
The CAE process chain is presented and software packages for various tasks such as linear and non-linear statics, dynamics, optimization, misuse and life are explained.
Further new subjects such as process simulation (casting, forming) are discussed.
Due to the rapid development in the field of CAD-integrated calculation tools, standard calculations are increasingly done in the design departments themselves. This trend will further intensify in future, since the scope and complexity of the calculation tasks to be accomplished by the calculation engineers keeps increasing.
Some examples of current chassis developments are given.

METALLIC GASKET MODELING USING MSC/PATRAN ADVANCED FEA (Acrobat 98K) #3399, 8 pgs.
Michael de Jesus Fernandes--Sabó Indústria e Comércio Ltda, Brazil

ABSTRACT: This work presents the modeling methodology for multi-layer and single-layer-steel gaskets, MLS and SLS. Among the approached themes discussed are some concepts regarding metallic gaskets, the design methodology itself, main considerations and assumptions, as well as the most common problems in regards to the input data acquisition, and in the convergence process. The entire approach is carried out considering a fictitious problem example.

MSC.ACUMEN EXPERT SYSTEM ACCELERATES TRUCK STRUCTURE DESIGN (Acrobat 664K) #3199, 21 pgs.
Les Grundman--Navistar International Transportation Corp.
David Bremmer, Sue Rice, and Geetha Bharatram--MSC.Software Corporation
Tom Phillips--Thermal Engineering Services, Inc.

ABSTRACT: Navistar Technical Engineering Center has teamed with MSC to exploit a new technology with the goal of significantly enhancing the impact of concurrent simulation on the truck structure design process. MSC.Acumen was used to build an expert system of designer tools. Design Engineers use these tools to perform up-front concurrent simulation, yielding the same quality of results that the dedicated simulation experts produce. The specific best practices and methods for simulating particular design categories were captured from the experts at the NTEC structural analysis group and cast into customized and automated applications.
By using this system, component structural performance takes place on the same day that the design form is first rendered in CAD, as opposed to waiting in a queue for 4-to-6 weeks. If fact, design iteration for changes of material dimension, shape, or structural reinforcements is now supported by high quality simulation on the same day.
The custom MSC.Acumen applications are unique because they drive a Navistar specific process. They serve the collaboration and review process through automatic output of supporting data and simulation results in the form of web page HTML reports.
Navistar has selected two "work flow categories" for the first application set. They consist of eleven different "simulation templates" for structural brackets. These categories were chosen as very common and frequently designed structural components. The "simulation templates" will therefore see a high usage rate and yield the maximum impact to the design process. An additional benefit is that the structural analysis group experts are freed to pursue more complex and challenging tasks.

OPTIMIZATION OF CAR COMPONENTS USING MSC/CONSTRUCT (Acrobat 1.9MB) #2099, 15 pgs.
Dr. F. Dirschmid--IABG

ABSTRACT: New CAE tools are necessary to fulfill the increasing demands for new car components. Typical demands are lightweightness, costs and developing time. Efficient tools and methods have to be used in the very early stage of development to achieve these goals. As soon as the design space, the boundary conditions and the loads are fixed, the topology optimization is an appropriate method to define a first design of the component. The topology optimization is a method that change the density and stiffness distributions in an iterative process to achieve a homogeneous stress distribution. This design proposal must be transferred in a real component by taking into account manufacturing and design points of view. The industrial application of this optimization method using MSC/CONSTRUCT is demonstrated in this paper for different car components.

STRUCTURAL OPTIMIZATION IN VEHICLE DEVELOPMENT (Acrobat 878K) #0899, 10 pgs.
Leo W. Dunne--CDH GmbH

ABSTRACT: This paper presents an overview of structural optimization and some closely related subjects in the automobile industry. An historical review of the development of structural optimization is given. Some of the fundamental steps which were taken and the nature of the problems that had to be overcome will be highlighted. The current state of technical affairs relating to the optimizer algorithms, analysis and pre/post processing is reviewed, considering theoretical as well as application oriented aspects. Finally, the application of structural optimization during the development process of an automobile is discussed, including identification of its major benefits. Examples and case studies will demonstrate the applicability and limitations of structural optimization in daily engineering practice. The paper ends with a review of future trends in structural optimization applications and their implications.

Civil Structures

ANALYSIS OF HYPERBOLIC SHELL NATURAL DRAUGHT COOLING TOWERS USING MSC/NASTRAN (Acrobat 623K) #3994, 14 pgs. V. S. N. Raju -- A.P.S.E Board/Hyderabad, Andhra Pradesh

ABSTRACT:

IMPACT ANALYSIS OF A CONCRETE STORAGE CONTAINER (Acrobat 6MB) 1996, 21 pgs. H.P. Lee--Ontario Hydro

ABSTRACT

THE INFLUENCE OF PHASE-DIFFERENCE EFFECTS ON EARTHQUAKE RESPONSE OF CABLE-STAYED BRIDGES (Acrobat 294K) #3794, 9 pgs. Hongye Zhou -- China Academy of Railway Sciences Youping Chen -- China Academy of Railway Sciences

ABSTRACT

NON-LINEAR FINITE ELEMENT ANALYSIS OF REINFORCED CONCRETE MEMBERS USING MSC/NASTRAN (Acrobat 64K)1996, 10 pgs. Sreekanta Das--University of Wollongong Dr. Muhammad N.S. Hadi--University of Wollongong

ABSTRACT

This paper presents the uses of MSC/NASTRAN and advantages of using this software for non-linear analyses of RC members. Brief discussion on modeling procedures and discussion of results of three RC shallow beams are also presented to illustrate the degree of accuracy in results which could be achieved from non-linear post-yielding analyses of R.C. members by using MSC/NASTRAN.

PENETRATION ANALYSES DUE TO PIPEWHIP LOADS (Acrobat 448K)1996, 20 pgs. H.P. Lee--Ontario Hydro

ABSTRACT

REFINED ANALYSIS FOR SOIL-PIPE SYSTEMS (Acrobat 765K) #3894, 19 pgs. Yohchia Chen, Ph.D., P.E.-- The Pennsylvania State University

ABSTRACT

Composites

COMPOSITE BLADE DESIGN FOR BIRDSTRIKES USING MSC/DYTRAN: AN AUTOMATED APPROACH TO ENABLE RAPID SCREENING OF COMPOSITE LAY-UPS (Acrobat 2.6MB)1996, 10 pgs. John C. Lambert--Hamilton Standard, a Division of United Technologies

ABSTRACT

AN INTEGRATED FEA AND DESIGN OPTIMIZATION SYSTEM FOR COMPOSITE STRUCTURES (Acrobat 704K)1996, 16 pgs. Craig S. Collier--Collier Research & Development Corporation

ABSTRACT

A SIMPLE MODEL TO ANALYZE THE THROUGH-WIDTH DELAMINATIONS (Acrobat 96K)1996, 8 pgs. Francisco Kioshi Arakaki--EMBRAER-Empresa Brasileira de Aeronáutica Sérgio Frascino Müller de Almeida--ITA-Instituto Tecnológico de Aeronáutica ABSTRACT: In the most of the studies, if not all, the composite stress analysis is made considering the unidirectional graphite/epoxy prepreg (tape). However, in the practical design, in many situations it is interesting to use the woven graphite/epoxy prepreg (cloth). Therefore, this report outlines the preliminary results in through-width delamination specimens made of graphite/epoxy prepreg tape with graphite/epoxy prepreg cloth. Initially, a simple model based on the results presented in ref. [ 1 ] was made, analyzed and compared with MSC/NASTRAN, ref. [ 2 ]. This model considered a two-dimensional geometrically nonlinear finite element. The results obtained by MSC/NASTRAN in finite element model with 153 nodes and 128 four-node isoparametric elements were in very good accordance when compared to classical theory, presented in ref. [ 1 ]. The model contained four sub-structures with a total of 813 nodes and 740 four-node isoparametric elements. The next step was to analyse through-width delaminations in specimen made of graphite/epoxy tape with graphite/epoxy cloth. This specimen not only contains two types of graphite/epoxy, tape and cloth, but also presents a non-symmetrical laminated. The results obtained by MSC/NASTRAN were compared with the classical theory and were found to be in very good accordance. This report shows how these results were obtained.

1993-1999 MSC Users' Conference Proceedings

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