MSC Software Corporation

1993-1999 MSC Users' Conference Proceedings

Process Strategies
Space
SuperModel & PATRAN
Shape Optimization
Spacecraft
Stress Analysis
Superelements
Test/Analysis Correlation
Testing and Applications
Thermal Analysis

Nonlinear Analysis

BUCKLING AND GEOMETRIC NONLINEAR ANALYSIS OF A TIE ROD IN MSC/NASTRAN VERSION 68 (Acrobat 630K) #1594, 15 pgs. George Campbell -- Ford Motor Company Wen Ting -- Ford Motor Company Peyman Aghssa -- The MacNeal-Schwendler Corporation Claus C. Hoff -- The MacNeal-Schwendler Corporation

ABSTRACT: The improved geometric capability in MSC/NASTRAN Version 68 is tested on a large scale finite element model of a tie rod. The static buckling load of a tie rod is analyzed. The results of the finite element model are compared with experimental results. The analysis is performed in three steps. First, linear buckling is analyzed with SOL 105. Second, a nonlinear static analysis with arc-length method is performed in SOL 106 to determine the instability behavior of the structure. In the last step, a nonlinear buckling analysis is done with restart into SOL 106 to determine the nonlinear buckling load. The tie rod has a strongly nonlinear behavior which is due to material yield and geometric nonlinear effects. It is shown that MSC/NASTRAN's computed buckling load agrees well with the experimental buckling load.

A DESIGN STAGE NON-LINEARISATION OF STIFFENED-COMPRESSION PANELS FOR LINEAR MSC/NASTRAN/ARIES MODELLING OF DIAGONAL TENSION FIELD SHELLS (Acrobat 1.61 MB) #3095, 22 pgs. S. Basic--Morrison Knudsen Corporation

ABSTRACT: This paper extends applicability of the fundamental theory of compressed shells to the refinement of a linear finite element model.

In light of Von Karman's, Trefftz's, Cox's and Marguerre's interpretations of elementary elastic instabilities, the compression end-load member quad element thicknesses have been determined to take into account, with a reasonable degree of approximation, the main non-linear responses of a shell subjected to compression. Consequently, the Modal and the Static Finite Element Method Results will be improved.

FULLY NONLINEAR HYPERELASTIC ANALYSIS OF NEARLY INCOMPRESSIBLE SOLIDS: ELEMENTS AND MATERIAL MODELS IN MSC/NASTRAN (Acrobat 1MB) #2995, 16 pgs. Katerina-D. Papoulia--MacNeal-Schwendler Corporation

ABSTRACT:

A NEW METHOD DEVELOPMENT TO PREDICT BRAKE SQUEAL OCCURRENCE (Acrobat 453K) #1494 , 12 pgs. Lajos I. Nagy -- Ford Motor Company James Cheng -- Ford Motor Company Yu-Kan Hu -- BQUAD Engineering, Inc.

ABSTRACT:

NONLINEAR ANALYSIS OF FREE FLIGHT ROCKETS USING MSC/NASTRAN (Acrobat 511K) #3694, 16 pgs. David S. Livshits -- TAAS - Israel Industries Ltd. David Saltoun -- MSI Engineering Software Ltd

ABSTRACT:

PRODUCTION ORIENTED NONLINEAR ANALYSIS OF SOLIDS AND STRUCTURES (Acrobat 917K) #0394, 14 pgs. H. D Hibbitt -- Hibbitt, Karlsson & Sorensen, Inc.

ABSTRACT:

SPACE STATION FREEDOM SOLAR ARRAY WING NONLINEAR TRANSIENT ANALYSIS OF PLUME IMPINGEMENT LOAD (Acrobat 767K) #3594, 17 pgs. C. C. Tang -- Lockheed Missile & Space Company

ABSTRACT:

STABILITY ANALYSIS OF PERFECT AND IMPERFECT CYLINDERS USING MSC/NASTRAN LINEAR AND NONLINEAR BUCKLING (Acrobat 1.48MB) #2795, 16 pgs.
M. H. Schneider, Jr.--McDonnell Douglas Aerospace
R. J. Feldes--McDonnell Douglas Aerospace
J. R Halcomb--MacNeal-Schwendler
C.C. Hoff--MacNeal-Schwendler

ABSTRACT:

STATIC TEST AND NONLINEAR ANALYSIS OF THE MAST FOR INTERNATIONAL SPACE STATION ALPHA SOLAR ARRAY WING (Acrobat 1.17MB) #2895, 21 pgs.
C.C.Tang--Lockheed Missiles & Space Company
A.J. Elliott--Lockheed Missiles & Space Company
Dr. M. L.Bowden--AEC-Able Engineering Company, Inc
S. Robinson--AEC-Able Engineering Company, Inc.

ABSTRACT:

THREE-DIMENSIONAL SLIDELINE CONTACT IN VERSION 68 (Acrobat 553K) #1694, 15 pgs.
Rakesh Allahabadi -- The MacNeal-Schwendler Corporation
Dianxiang Xiang -- The MacNeal-Schwendler Corporation
Detlef Liebe -- MSGmbH
Glenn C. Grassi -- The MacNeal-Schwendler Corporation
Peyman Aghssa -- The MacNeal-Schwendler Corporation
Behrooz K. Shahidi -- Ford Motor Company

ABSTRACT:

This paper shares the experience of using the MSC/NASTRAN slideline contact capability. It (a) demonstrates the capability through real life applications and (b) provides guidelines for effective usage.

VULNERABILITY ANALYSIS OF AIRCRAFT FUSELAGE SUBJECTED TO INTERNAL DETONATIONS
(Acrobat 990 K) #3494, 17 pgs.
Geetha Bharatram -- Wright Patterson AFB
Capt. Scott A. Schimmels -- Wright Patterson AFB
Dr. Vipperla B. Venkayya -- Wright Patterson AFB

ABSTRACT:

Two types of analysis will be addressed in this paper:

1. Fluid structure interaction (blast pressures and airframe interaction) using MSC/DYTRAN.

2. Joint and buckling analysis of a B-52 panel using MSC/DYTRAN.

The ultimate goal of the proposed analysis is to develop a vulnerability map of the entire fuselage. This map can be used to make cost effective decisions on hardening of the aircraft against bomb blasts.

Nonlinear Applications

LARGE DEFORMATION HYPERELASTIC ANALYSIS IN MSC/NASTRAN VERSION 67.5 (Acrobat 586K) #5693, 13 pgs.
Katerina-D. P. Papoulia -- The MacNeal Schwendler Corporation
Steve S. Hsieh -- The MacNeal Schwendler Corporation

ABSTRACT: Version 67.5 of MSC/NASTRAN includes finite deformation analysis for problems that involve large strain and large rotation. The material law is Green-elastic (hyperelastic) with a strain energy function of the generalized Rivlin type, extended to include the effect of compressibility at the nearly incompressible limit. The stress-strain relations are discussed in some detail as well as the approach taken to avoid the occurrence of volumetric locking. Examples are presented that illustrate the capabilities of the formulation to model problems with large strain and large rotation.

NONLINEAR SEISMIC ANALYSIS OF BRIDGES: PRACTICAL APPROACH AND COMPARATIVE STUDY (Acrobat 721K) #5793, 19 pgs.
Yohchia Chen, Ph.D., P.E. -- Pennsylvania State University

ABSTRACT: A simplified numerical model with an efficient computational scheme is proposed for nonlinear seismic analysis of bridges. The results obtained from the simplified model are compared to those from the refined model and other methods. The proposed model is shown to be especially effective for obtaining maximum responses, and is practical and economical. Effects of bridge skews on responses are also carefully examined. The paper concludes with a number of bridge examples and design recommendations.

NONLINEAR SUPERELEMENT ANALYSIS TO MODEL ASSEMBLY PROCESSES (Acrobat 1.09MB) #5993, 18 pgs.
Mark J. Stone -- Eastman Kodak Company
Vic Genberg -- Eastman Kodak Company

ABSTRACT: It is often desirable to know the residual effect of assembly processes on the final product. Although only a linear static analysis may be desired, the changes in loads and constraints throughout the assembly process prevent the use of a simple linear solution. If the product is fairly complex, it is often necessary to use a large finite element model. This paper describes the use of a single nonlinear solution (MSC/NASTRAN V66A SOL 66) using superelements to analyze a large model subjected to varying loads and constraints. As the load and support change in each subcase, the structural deflection changes by adding to or subtracting from the previous deformation state. The model used represents the High Resolution Mirror Assembly (HRMA) for NASA's Advanced X-Ray Astrophysics Facility (AXAF). The process represented is the alignment and assembly of the AXAF mirrors to the support structure.

SNAP-THROUGH BUCKLING ANALYSIS OF A SHALLOW GEODESIC DOME USING MSC/NASTRAN (Acrobat 758K) #5893, 24 pgs.
S. Loganathan, BSc Eng Civil (Hons), M. Eng, PhD -- BHP Engineering
R.C. Morgan, BE, M.Eng Sc MIE Aust -- BHP Engineering

ABSTRACT: This paper illustrates the nonlinear analytical and experimental study of a shallow geodesic dome comprising thin walled circular hollow sections. A 156-member shallow geodesic dome that has a rise to span ratio of 1:10 (i.e. a rise of 0.6m to span of 6.0m) was constructed and tested experimentally. The present investigation is focused to study the snap-through phenomena of the dome subjected to a static load at the centre of the dome. The dome is discretized as 156 beam elements and its perimeter supports are assumed as ideal pin supports. Displacement control of the load point was employed to trace snap-through and this prevents any possible dynamic jump in the vicinity of the snap-through region. Experimental observation shows that the members near the loading point deformed severely under the applied load without resulting in any damage to the welded joints, apart from material yielding in certain members.

MSC/NASTRAN Version 67 installed on the BHP Research CRAY-YMP (EL) SuperComputer was used as the numerical tool to validate the complex nonlinear behaviour of the dome. The results of geometrical and material nonlinear analysis of the dome from MSC/NASTRAN compare well with the experimental results for cases where the displacements can be reasonably measured with the linear transducers employed. A second nonlinear large displacement analysis was carried out with MSC/NASTRAN on a Schwedler dome in which the connection details are based on the Harley Spaceframe structures. The Schwedler dome considered has a rise-to-span ratio of 1:4 (i.e., a rise of 2.5 m to span of 10.0 m).

Nonlinear Methods

IMPROVEMENTS IN LINEAR BUCKLING AND GEOMETRIC NONLINEAR ANALYSIS FOR MSC/NASTRAN'S SHELL ELEMENTS (Acrobat 543K) #4993, 26 pgs.
Claus C. Hoff -- The MacNeal-Schwendler Corporation

ABSTRACT:

NONLINEAR ANALYSIS USING A MODAL BASED REDUCTION TECHNIQUE (Acrobat 530K) #5193, 13 pgs.
D. Shalev -- Israel Aircraft Industries
A. Unger -- Israel Aircraft Industries

ABSTRACT:

NONLINEAR GAP-TYPE SOLUTIONS USING A LINEAR F.E.A. CODE (Acrobat 733K) #5093, 13 pgs.
R. D. Hilton -- Bell Helicopter Textron

ABSTRACT:

Many common FEA codes do not support gap elements; for those that do, adding a gap element complicates the solution by requiring extensive changes to the linear model, and by increasing the CPU time required (often several times over). As the gap behavior can vary from one loading condition to the next, a separate solution for each condition must be obtained.

The Enforced Strain Method uses an approach in which a compensating enforced strain is used to give linear elements gap-like load vs. deflection behavior. The technique can be used with linear FEA codes that do not support gap elements, or can be used as an alternate solution for gap-capable codes. Benefits of the method are reduced CPU requirements, the ability to run multiple loading cases, and no need for superelements.

The Enforced Strain Method is a more efficient gap solution, particularly when a given model has a relatively small proportion of gaps, and when multiple loading conditions are required. An example problem is presented in which the required CPU time was reduced by 43% as compared to the fastest MSC/NASTRAN gap solution. Though presented as a program external to MSC/NASTRAN, the method could be implemented through DMAP alters to the standard linear static solution. Run as a DMAP, CPU time savings for the example problem would have increased from 43 to 66% as compared to MSC/NASTRAN's nonlinear gap Solution 66.

THREE DIMENSIONAL SLIDELINE CONTACT (Acrobat 938K) #4893, 22 pgs.
Rakesh Allahabadi --The MacNeal-Schwendler Corporation

ABSTRACT:

The finite element formulation for both contact and friction is based on the penalty method. But, the user need not specify the penalty values as the program automatically calculates them. The slide line element force vector and the stiffness matrix are derived from a variational principle using a consistent linearization procedure. The formulation is capable of modeling nonlinear contact geometry and inelastic material behavior including large deformation.

The three dimensional slideline contact is a standard feature in Version 68 for quasi-static analyses (SOL 106). However, a special DMAP is required for Version 67.5.

Nonlinear Transient Response

APPLICATION OF MSC/DYTRAN TO THE HYDRODYNAMIC RAM PROBLEM (Acrobat 1.43MB) #1295, 20 pgs.
Geetha Bharatram--Wright Patterson AFB
Capt. Scott A. Schimmels--Wright Patterson AFB
Dr. Vipperla B. Venkayya--Wright Patterson AFB
EXTENDING MSC/DYTRAN FOR THE NUMERICAL SOLUTION OF THE NAVIER-STOKES EQUATIONS (Acrobat 1.08MB) #5295, 21 pgs.
Ortwin Ohtmer--California State University, Long Beach

NONLINEAR IMPACT ANALYSIS OF INTERNATIONAL SPACE STATION ALPHA MODULE BERTHING USING MSC/NASTRAN (Acrobat 1.59MB) #5095, 20 pgs.
Timothy S. West--McDonnell Douglas Aerospace
David A VanHorn--McDonnell Douglas Aerospace
John R LeCour--McDonnell Douglas Aerospace
Mitchell W. Usrey--McDonnell Douglas Aerospace

ABSTRACT: MSC/NASTRAN nonlinear gap element modelling techniques were implemented to analyze the impact between berthing modules and on-orbit structure during assembly of International Space Station Alpha (ISSA). Component mode synthesis techniques were used to create superelements to reduce the analysis set degrees of freedom during the nonlinear analysis. Superelements were again used in structural response recovery, where the impact forces were applied to the reduced ISSA model in modal transient analysis and responses were recovered for a large number of response items. This procedure is illustrated with three different examples.

THREE-DIMENSIONAL SIMULATION OF CLOSED-DIE FORGING PROCESS USING MSC/DYNA (Acrobat 805KB) #1395, 18 pgs.

Mary Wicklin Schleider--Mercer University Engineering Research Center

ABSTRACT: A three-dimensional, elastic-plastic finite element model using MSC/DYNA was used to simulate a closed-die forging process. An H-shaped cross-section forging die and a rectangular billet were modelled. Die/billet interface contact friction, and die geometry were varied to determine the effects of these variables on material flow, strain, and die force.

USE OF MSC/NASTRAN IN PREDICTING STRUCTURAL RESPONSE TO AN UNDERWATER EXPLOSION (Acrobat 430KB) #5195, 12 pgs.

Kevin E. Arden--Newport News Shipbuilding

ABSTRACT: The prediction of the response of submerged structures to underwater explosions requires solving a fluid-structure interaction problem. This paper is based on experiences with MSC/NASTRAN's interface with the USA (Underwater Shock Analysis) code. The phenomena associated with an underwater explosion and how MSC/NASTRAN/USA is used to solve the problem will be discussed. As a validation, analytical results will be compared to a test. The statements and opinions herein are those of the author and do not necessarily represent Newport News Shipbuilding.

VULNERABILITY AND SURVIVABILITY ANALYSIS OF AIRCRAFT FUSELAGE SUBJECTED TO INTERNAL DETONATIONS (Acrobat 1.13MB) #1195, 17 pgs.

Young Moon--Wright Patterson AFB

Geetha Bharatram--Wright Patterson AFB

Capt. Scott Schimmels--Wright Patterson AFB

Dr.Vipperla Venkayya--Wright Patterson AFB

ABSTRACT: The Air Force, in support of the FAA's (Federal Aviation Administration) Transport Aircraft Survivability Program (TASP), is conducting an extensive test and analysis procedure to determine the vulnerability of commercial airplanes to internal explosions. The program is in response to increasing terrorist activities against civilian targets resulting in loss of life, property damage and general disruptions.

The purpose of this program is to develop survivability strategy to mitigate the effects of internal explosions. Airframe damage is viewed from two aspects, related but requiring different approaches for assessment. The first issue is the damage immediately after explosion and the immediate damage is assessed using simpler local models. The second issue is the safety of post explosion flight which is examined by global models.

Vulnerability maps of the fuselage based on various failure scenarios are being developed for the purpose of examining airframe hardening options.

All analysis results are compared to those obtained from the test program, and the simulations are performed using both MSC/NASTRAN and MSC/DYTRAN.

Numerical Methods

A BREAKTHROUGH IN PARALLEL SOLUTIONS OF MSC.SOFTWARE (Acrobat 260K) #2899, 12 pgs.
Louis Komzsik, Paul Vanderwalt, Petra Poschmann, and Reza Sadeghi--MSC.Software Corporation
Stefan Mayer--MSC.Software Corporation, München, Germany

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 processing and is now ready to deliver MSC.NASTRAN V70.7 and MSC.MARC V9.1, both of which contain very important new parallel features.
This paper describes these exciting features and provides preliminary performance results. We believe that these systems mark the best in parallel performance in commercial finite element analysis ever and present a breakthrough in parallel computing in our market.

DISTRIBUTE MEMORY PARALLEL MSC.NASTRAN ON AN IBM WORKSTATION CLUSTER AT FORD COLOGNE (Acrobat 130K) #3099, 16 pgs.
Ulrich Viersbach, Dr. Matthias Weinert, and Christian Wilmers--Ford Werke Aktiengesellschaft, Germany
Dr. Stefan Mayer--MacNeal-Schwendler GmbH, Germany

ABSTRACT: MSC.NASTRAN is the main structural FE code and the second most used CAE code on compute servers at Ford worldwide. To reduce costs, alternative ways of computing are being investigated such as using idle cycles on the large number of available Ford workstations. While smaller analyses run efficiently on single workstations, more complex calculations require larger computer resources as potentially available with several workstations clustered together using a distributing memory parallel code.
The presented paper outlines results from evaluating and benchmarking a V70.7 development version of the distributed memory parallel MSC.NASTRAN code on an IBM RS/6000 model 590 workstation cluster at Ford Cologne. It covers linear static (solution 101), normal modes (solution 103) and direct frequency response (solution 108) analyses which were carried out for the first time ever on a workstation cluster. Cluster turnaround times are compared with those on IBM compute servers and Cray C90.
The evaluation showed that the development version has great potential for typical jobs used for the analysis of Ford body structures. Good speed-up with an increasing number of processors is achieved on the workstation cluster. The cluster with 8 workstations showed better turnaround times than the Cray C90 for SOL101 benchmark cases. When using latest technology workstations the cluster is expected to show even better turnaround times with also superior performance to the C90 for SOL103 and SOL108. The turnaround target of overnight completion could be achieved with 8 cluster workstations for all benchmark cases. The IBM SP compute server at MSC.Software's office in Los Angeles which is equipped with similar processors as the cluster workstations showed similar performance as the cluster. The IBM SP compute server at IBM's benchmark center at Poughkeepsie/USA using 8 latest technology processors and a superior I/O subsystem was performing better than the workstation cluster with 8 processors and the Cray for all benchmark cases.
As next steps Ford is planning to carry out runs with the distributed memory parallel version 70.7 on a Ford compute server once this version is officially released and consider production implementation depending on results. Ford is also planning to evaluate the code with our largest CAE models on the above workstation cluster and in a production environment. Ford will encourage MSC.Software to implement several improvements to MSC.NASTRAN such as the integration of the code with a workload management package to enhance cluster robustness.

NVH

ACOUSTIC PREDICTION MADE PRACTICAL: PROCESS TIME REDUCTION WITH PRE/SYSNOISE, A RECENT JOINT DEVELOPMENT BY MSC & LMS (Acrobat 260K), #3699, 10 pgs.
L.Cremers, O. Storrer, and P. van Vooren--LMS International NV

ABSTRACT: Finite element models for structural dynamic analysis and boundary elements models for acoustic radiation analysis have different meshing requirements. Acoustic boundary element analysis requires a mesh of the sound radiating surface with a uniform discretization of about six degrees of freedom per shortest acoustic wavelength whereby small details, relative to the acoustic wavelength, can be omitted. In most cases the acoustic analyst needs to generate the acoustic boundary element mesh from the original detailed structural finite element mesh as no geometry information is available for the model. This so-called mesh coarsening process involves in general four phases, i.e. mesh processing, subdomaining, creation of surfaces and re-meshing. Pre/SYSNOISE, a joint-development by MSC and LMS, is a powerful tool to help the acoustic analyst in this tedious task. It combines both the geometry and finite element meshing tools of v8.0 and an advanced set of automatic mesh coarsening routines. The different techniques involved in the mesh coarsening process will be explained along with a practical real-life example.

BRAKE ANALYSIS AND NVH OPTIMIZATION USING MSC.NASTRAN (Acrobat 423K) #1699, 15 pgs.
Dr. Himanshu Misra--NEC Systems, Inc.
Dr. Wayne Nack--General Motors Corporation
Dr. Tom Kowalski--MSC.Software Corporation
Dr. Louis Komzsik--MSC.Software Corporation
Dr. Erwin Johnson--MSC.Software Corporation

ABSTRACT: Brake Analysis and NVH (Noise, Vibration and Harshness) Optimization have become critically important areas of application in the Automotive Industry. Brake Noise and Vibration costs approximately $1Billion/year in warranty work in Detroit alone. NVH optimization is now increasingly being used to predict the vehicle tactile and acoustic responses in relation to the established targets for design considerations. Structural optimization coupled with frequency response analysis is instrumental in driving the design process so that the design targets are met in a timely fashion. Usual design targets include minimization of vehicle weight, the adjustment of fundamental eigenmodes and the minimization of acoustic pressure or vibration at selected vehicle locations.
Both, Brake Analysis and NVH Optimization are computationally expensive analyses involving eigenvalue calculations. From a computational sense and the viewpoint of MSC.Nastran, brake analysis exercises the CEAD (Complex Eigenvalue Analysis Dmap) module, while NVH optimization invokes the DSADJ (Design Sensitivity using ADJoint method DMAP) module. In this paper, two automotive applications are presented to demonstrate the performance improvements of the CEAD and DSADJ modules on NEC vector-parallel supercomputers. Dramatic improvements in the DSADJ module resulting in approx. 8-9 fold performance improvement as compared to MSC.Nastran V70 were observed for NVH optimization. Also, brake simulations and experiences at General Motors will be presented. This analysis method has been successfully applied to 4 different programs at GM and the simulation results were consistent with laboratory experiments on test vehicles.

FUTURE TECHNIQUES FOR HIGH FREQUENCY NVH (Acrobat 423K) #0799, 11 pgs.
Stan Posey and Cheng Liao, PhD--SGI Mtn View, CA
Christian Tanasescu, PhD--SGI Munich, GR

ABSTRACT: The use of NVH analysis provides essential benefits towards designing vehicles for ride comfort and quietness, an increasingly competitive advantage in today's global automotive market. Requirements for NVH analysis at increasingly higher excitation frequencies is driving NVH modeling promoters beyond practical limits for conventional NVH methods. This paper examines details behind conventional NVH practice, NVH modeling directions for the future, and an alternative to conventional NVH that will allow future modeling targets to be achieved.

LINEARISATION OF STIFFNESS AND DAMPING CHARACTERISTICS OF RUBBER VANISHES IN VEHICLE DYNAMICS BY USING FREQUENCY RESPONSE ANALYSIS OF MSC.NASTRAN (Acrobat 780K) #1399, 14 pgs.
Dr. Plank and Dr. Merk--AUDI AG
Dr. Stefan Dömök--Peters & Zabransky, Germany

ABSTRACT: For vehicle dynamics analysis detailed modelling of bushes is necessary. The following paper describes different possibilities to use measurement data of rubber bushes by linearisation of stiffness and damping characteristics in frequency response analysis.

A NONLINEAR SIMULATION OF CAR VIBRATION BY MSC/NASTRAN (Acrobat 943K) #2999, 12 pgs.
Sergey Sergievsky and Sergey Purgin--OJSC "GAZ"
Boris Shatrov--The MacNeal-Schwendler GmbH, Russia

ABSTRACT: Setting the task of creating a modern competitive vehicle, the designers need the more exact estimation of the degree of their design optimum at the early stages of the work. According to this, besides the traditional methods of analysis (static analysis, normal modes analysis and frequency response analysis), the transient response analysis of the car real loading becomes more interesting. This type of analysis provides the data, which are the close analogue to the test results and allows, later on, to go over to the fatigue analysis.
In this article the example of the nonlinear simulation of the car vibration in time domain by MSC/NASTRAN is considered.

SIMULATION OF VEHICLE PANELS WITH MULTILAYER DAMPING TREATMENT (NOT PRESENTED) (Acrobat 1.1MB) #3999, 17 pgs.
Shu Wang and Hinne Bloemhof--Rieter Automotive, Switzerland

ABSTRACT: By using equivalent material parameters and a special equivalent shell element, multi-layer damping treatments can be integrated into simulations of structural vibrations without significan increase of either modelling or computing efforts. The treatment representations are used to conduct classical single-layer FE calculations and determine the frequency response functions of the structure in which the individually treated panels (non-flat) are now included. The procedure presented here does not increase the number of active degrees of freedom, so that it is possible to include the effect of these treatments in large system level models. Two representative examples have been numberically investivgated and a practical aplication of the procedure to a real car floor has been conducted (comparing simulation with measurement). These examples confirm the accuracy, the efficiency and the flexibility of the procedure.

Optimization

DESIGN SENSITIVITY ANALYSIS FOR DURABILITY DESIGN OF BODY STRUCTURES (Acrobat 655KB) #4895, 19 pgs.
E Y. Kuo--Ford Motor Company
S. G. Kelkar--Ford Motor Company
R Nagpal--Ford Motor Company
ABSTRACT: Design sensitivity analysis (DSA) computes the derivatives of structural response quantities (e.g., displacements, stresses, modal frequencies, mode shapes) with respect to design variables (e.g., cross-sectional properties such as area, moments of inertia, torsional constant). These derivatives, defined as design sensitivity coefficients, give the designer a feel as to how the structure will respond to a proposed design change. Although the general concept of DSA has been well established, the application of this method to vehicle body durability design is relatively new. The current paper examines the relation between the body overall stiffness/strength characteristics and fatigue life. It also demonstrates how DSA can be employed to effectively identify design variables most affecting fatigue life through the body overall stiffness/strength evaluations. The methods and concepts are demonstrated using a very simplified finite element model which conceptually simulates a body structural system.

HANDLING OF WELDS IN SHAPE VECTORS GENERATION FOR FINITE ELEMENT SHAPE OPTIMIZATION - A CASE STUDY (Acrobat 33K) #2498, 5 pgs.
Murali M.R. Krishna--DANA Corporation

ABSTRACT: Design analysts, who work with finite element shape optimization, face a daunting task of handling welds. When the designer wants to find the optimum width of the leg of a bracket, which is welded to a base rail, the analyst has to remove the old welds, remodel and re-create new welds after extension of the bracket, and iterate. This method is not suitable for shape optimization. A numerical interpolation method based on 'Autodv', has been recommended to handle welds without remodeling. This method is very effective for finite element shape optimization. A case study has been given to illustrate the method using MSC/NASTRAN.

ABSTRACT: Synthetic responses in MSC/NASTRAN allow the user to combine responses, design variables, and grid locations to define new responses that can be incorporated into a structural design task. This paper indicates how this capability can be applied in a wide variety of applications. Four examples are presented showing the use of this capability to (1) minimize the maximum stress response, (2) create mean-square responses (3) include Johnson/Euler buckling conditions in the design task, and (4) perform topology optimization.

MSC/CONSTRUCT - FEATURES AND CAPABILITIES (Acrobat 2.3MB) #0898, 18 pgs.
Dr. Hans Sippel--MSC, Munich

ABSTRACT: For design engineers and analysts MSC/CONSTRUCT¹⁾ provides an exceptionally fast and easy-to-use, conceptional design tool consisting of two options:

MSC/CONSTRUCT TOPOLOGY is the topology optimization option, which distributes material within a design space envelope based on the optimum load paths.

MSC/CONSTRUCT SHAPE is the non-parametric shape optimization option, which homogenizes the stress distribution (Fully Stressed Design).

Both of these options are FEM-based and use an efficient optimality criteria technique. In the optimization cycle MSC/NASTRAN is used as the analysis engine. This guarantees reliable results and highest performance.

MSC/CONSTRUCT V2.5 was released in Q3/98. Major highlights are:

1. A graphical user interface within MSC/PATRAN
2. A restart option
3. High performance improvements which significantly increase the throughput
4. An automatic shape basis vector generation for MSC/NASTRAN's SOL 200 by MSC/CONSTRUCT

Especially items 3. and 4. will be presented by customers' real life examples.

NASOPT: A FLEXIBLE OPTIMIZATION CAPABILITY FOR MSC/NASTRAN (Acrobat 64KB) 1996, 14 pgs. Harold Thomas--Structural Optimization Specialists
NONLINEAR ADAPTIVE ANALYSIS VIA QUASI-NEWTON APPROACH WITH MSC/NASTRAN
(Acrobat 802KB) #1394, 16 pgs.
Ortwin Ohtmer -- California State University, Long Beach

ABSTRACT: The Quasi-Newton method has proven to be the most efficient optimization method. The purpose of this paper is to apply this numerical procedure for optimization problems as well as large deflection analysis and animation. A FORTRAN program developed to calculate constrained optimization problems is used as the basic code within an iterative nonlinear adaptive analysis. The new numerical procedure calculates the displacements of an elastic structure due to given loading conditions. Then the displacements are added to the joint coordinates. In the deformed position the degrees of freedom of the structure are supported and the negative displacements are applied as loadings, to move the structure back to the old undeformed position. The difference of the reaction forces in both positions specifies the geometric nonlinear adaptive loading conditions. These additional forces are applied in an iteration procedure, until equilibrium is achieved. The software ME-BANK (Mechanical Engineering Program-Bank), written in C-language, was developed to execute MSC/NASTRAN and a constrained optimization FORTRAN-code via the SYSTEM-function within an iteration procedure.

NVH OPTIMIZATION ON NEC SUPERCOMPUTERS USING MSC/NASTRAN (Acrobat 1.7MB) #0599, 14 pgs. Dr. Himanshu Misra--NEC Systems, Inc. Dr. Erwin Johnson and Dr. Louis Komzsik--The MacNeal-Schwendler Corporation

ABSTRACT: NVH (Noise, Vibration and Harshness) Optimization has now gained popularity in driving the automotive design process using frequency response analysis of detailed full vehicle structural-acoustic models. Usual design targets include minimization of vehicle weight, the adjustment of fundamental eigenmodes and the minimization of acoustic pressure at selected vehicle locations. Typical NVH Optimization analyses require considerable computational resources, both in terms of cputime as well as memory. The availability of state-of-the-art high performance hardware coupled with software advances and improved methodology has made it possible to solve complicated NVH dynamic response problems very efficiently.
With the introduction of Adjoint Sensitivity Method in V70, MSC/NASTRAN has been increasingly used to perform large NVH Optimization analyses that were unimaginable with the Direct Method. The Adjoint Method usually requires a fraction of the computer resources to produce sensitivity coefficients as compared with the Direct Method. However, for extremely large NVH Analyses, the sensitivity calculations are very demanding in terms of cputime, especially in the context of Vector machines. The calculation of sensitivity coefficients is done inside the DSADJ module of MSC/NASTRAN. For V70.5 and V71, NEC initiated a project with MacNeal-Schwendler Corporation to address the performance bottleneck in the DSADJ module of MSC/NASTRAN. The DSADJ Module Performance Enhancement Project was done with the guidance of MSC and these enhancements are available exclusively on NEC platforms.
The DSADJ module was totally redesigned to improve vectorization and to exploit the vector architecture of NEC SX-4 and SX-5 Series Supercomputers. In this paper, automotive customers’ NVH Optimization applications are presented to demonstrate the performance improvements of the DSADJ module. Dramatic improvements in the DSADJ module resulting in approximately 8-9 fold performance improvement as compared with V70 were observed for NVH Optimization. With the tremendous improvements in the performance of the DSADJ module, and the fact that the eigenvalue analysis involved in NVH Optimization is inherently highly vectorized, NEC Supercomputers are well suited for running large NVH Optimization Analyses using MSC/NASTRAN.

OPTIMIZATION OF DAMPED STRUCTURES IN THE FREQUENCY DOMAIN (Acrobat 625KB) #2893, 18 pgs.
Tsung-hsiun Li -- Iowa State University
James E Bernard -- Iowa State University

ABSTRACT: This paper presents a way to efficiently compute the sensitivities of steady state resonant response and discusses the utility of these sensitivities in redesign and optimization. The resonant response sensitivities are calculated by combining the new capabilities of MSC/NASTRAN v67 in SOL 108,111 and DMAP solution sequences. Two examples illustrate the approach.

OPTIMIZATION TRIAL ANALYSIS OF A JOURNAL/THRUST BEARING STRUCTURE (Acrobat 779KB) #2993, 19 pgs.
Takao Miki -- Mitsubishi Heavy Industries, Ltd.
Mitsuru Kondo -- Mitsubishi Heavy Industries, Ltd.
Fumio Mizuguchi -- Mitsubishi Heavy Industries, Ltd.
Yasuhisa Ogino -- Ryoyu System Engineering, Ltd. ABSTRACT: Recently, due to the need to minimize structural weight and reduce material cost, several programs are offering optimization capabilities. An optimization capability has been added to MSC/NASTRAN in V66 and has been enhanced in V67. With V68, it will be also possible to optimize the shape of a structure. This paper presents a trial analysis of optimization capability using the current version (V67) performed on a journal/thrust bearing structure. While supporting the static load and satisfying design constraints on stress and displacement, weight is minimized. This trial analysis demonstrates the effectiveness of the optimization capability in MSC/NASTRAN in achieving satisfactory results while saving much of the designer time which is currently used in a manual iterative optimization procedure. Improvements such as easiness of use and shape optimization would help to put this capability to extensive use in design.
OPTIMAL DESIGN OF A SIMULATOR MODULE FRAME (Acrobat 384KB) #1595, 6 pgs. S.C. McIntosh, Jr.--McIntosh Structural Dynamics, Inc. Erwin H. Johnson--MacNeal-Schwendler Corporation ABSTRACT: The support frame of a simulator module for the entertainment industry is designed to meet stiffness and strength conditions while minimizing the weight. As such, it represents a straightforward design optimization task with the novelty associated with the nonconventional vehicle that is being designed. A simple frame structure is used for the design. MSC/NASTRAN's ability to synthesize property values allows considerable generality in the specification of cross-sectional dimensions. This paper presents the design concept, the loading conditions, and the design constraints. The MSC/NASTRAN model is discussed, and the results of the the optimization task are given. The initial arbitrary design was infeasible, with a 33 percent weight increase necessary to achieve the final optimal design.
OPTIMUM DESIGN OF A LIGHTWEIGHT TELESCOPE (Acrobat 560KB) #1495, 13 pgs.
Victor Genberg--Eastman Kodak Company ABSTRACT: The sizing and shape capability of MSC/NASTRAN was applied to the design of an orbiting lightweight telescope. Design variables included dimensions of the primary mirror, mounts, and metering structure. Constraints were applied to optical performance measures such as image motion and surface distortion, as well as the conventional stress, frequency, and buckling behavior.
PARAMETRIC DESIGN/ANALYSIS WITH MSC/PATRAN- A NEW CAPABILITY (Acrobat 4.7MB) #0899, 17 pgs. James G. Crose, Douglas A. Marx, Mark Kranz, Paul Olson and Carl Ball--MacNeal Schwendler Corporation
PRACTICAL GLOBAL-LOCAL DESIGN OPTIMIZATION OF VEHICLE BODY-IN-WHITE STRUCTURES (Acrobat 1MB) 1996, 10 pgs. Paramjot Bedi--Ford Motor Company Metin Dede--Ford Motor Company Greg Moore--The MacNeal-Schwendler Corporation
SHAPE OPTIMIZATION OF A CAST TURBINE MANIFOLD (Acrobat 1.4MB) 1996, 13 pgs. W.A. Holzmann--GenCorp Corporation V.J. Wagner--The MacNeal-Schwendler Corporation ABSTRACT: This paper discusses the application and lessons learned using the Shape Optimization capabilities in MSC/NASTRAN to analytically modify the existing design of a cast turbine manifold. Figure 1 shows a model of a typical cross section of the manifold. The objective of the analysis was to minimize weight while satisfying several load conditions as well as manufacturing and assembly constraints. Using MSC/PATRAN, a solid finite element wedge model of the cross section of the manifold was created. Basis vectors were generated with the analytical boundary method and used as shape design variables. The approach and results are discussed, as well as recommendations for future production use of the optimization capability.

SHAPE OPTIMIZATION USING SHAPE BASIS VECTORS (Acrobat 428KB) #4795, 9 pgs. Jane Zhang--Ford Motor Company

ABSTRACT: Most shape optirnization methods require parametric modeling and automatic mesh generation. However, there are no robust tools available for parametric modeling and automeshing. This has resulted in few applications of shape optimization to large-scale industrial structures. Recently, the reduced basis method was introduced in shape optimization. Because it does not require the parametric modeling and auto-meshing, it has found wide applications in the automotive industry. Research engineers in Ford Motor Company have incorporated the reduced basis method in their design software. Development engineers in MacNeal-Schwendler Corporation also implemented this method in MSC/NASTRAN. They recently released MSC/NASTRAN version 68 which provides shape optimization capability with the feature of reduced basis vectors. In this paper, the shape optimization capability in MSC/NASTRAN V68 is discussed. The Modified Thermal Load Approach (MTLA) for generation of shape basis vectors is described. A procedure is developed for generating and inputting these basis vectors to the MSC/NASTRAN The convergence characteristics and the efficiency of incorporating MTLA for MSC/NASTRAN optimization process are demonstrated through two numerical examples. The optimized results are presented and discussed.

SHAPE PARAMETERIZATION AND OPTIMIZATION USING THE BOUNDARY SHAPES CONCEPT
(Acrobat 1.10MB) #1194, 18 pgs.
Hemant D Patel -- The MacNeal-Schwendler Corporation

ABSTRACT: The concept of boundary shapes for parameterization of design boundaries in shape optimization is introduced. In this concept the boundary definition of the finite element geometry is designed. In addition the requirement for use of shape basis vectors with low mesh distortion properties is ideally satisfied by interpolating domain point sensitivity by applying the boundary shapes or forms as enforced displacements and updating the shape basis vectors at each design cycle based on current geometry. This results in smooth mesh changes and minimizes the need for intermediate remeshing for small to moderate design changes. To support ease of use and provide flexibility in the prescription of boundary shapes the concept of auxiliary boundary models as been incorporated in MSC/NASTRAN as an integral part of the analysis model. The boundary shapes are generated with auxiliary boundary model analysis by exploiting available options in static analysis of applied loadings and multiple boundary conditions. Basic design examples demonstrating the power of the boundary shape approach are presented.

STRUCTURAL OPTIMIZATION WITH SOLUTION 2001 IN THE DESIGN PROCESS (Acrobat 2.57MB) #0494, 25 pgs.
Ingo Raasch -- BMW AG, Munich, Germany

ABSTRACT: The paper will explain the initiation and capabilities of S0L2001, a MSC/NASTRAN DMAP for structural optimization. The reminder will describe example problems, where 50L2001 has successfully used. Two examples show the achievements in concept design, followed by an example of a car body in white. Finally some shape optimization problems of engine components will be shown. A short outlook to the optimization capabilities of Version 68 will be given. In the conclusions it will be stressed that optimization is a very valuable (even in the meaning of $$) tool in the design process.

TOPOLOGY OPTIMIZATION USING MSC/NASTRAN (Acrobat 990KB) #1294,19 pgs.
B. P. Wang -- The University of Texas at Arlington
C M. Lu -- The University of Texas at Arlington
R.J. Yang -- Ford Motor Company: ABSTRACT: Recently, Bendsoe and Kikuchi developed a homogenization method which can be applied to find the optimal topology of a continuum in a fixed domain. The homogenization approach is based on an artificial but physical micro-structure whose properties are homogenized. Alternatively, it has been demonstrated that the solution of the optimum material distribution problem can be considerably simplified by employing a density-dependent isotropic material without a specific physical micro-structure. In this paper, topology optimization for minimum compliance under static loading and for maximum eigenvalue using this approach has been implemented using MSC/NASTRAN. Optimal topology for a plate under in-plane and bending loads is presented. Optimal material distribution for a plate to maximize the first frequency is also presented.

USE OF DSA ANALYSIS RESULTS FOR RITZ FAST ANALYSIS OF PERTURBED MODELS (Acrobat 228K) #0799, 11 pgs. Dr. J.N Bricout and J.M. Leduigou--Centre National d'Etudes Spatiales
USING OPTIMIZATION IN MSC/NASTRAN TO MINIMIZE RESPONSE TO A ROTATING IMBALANCE (Acrobat 1.11MB) #1695, 17 pgs.
Ted Rose--MacNeal-Schwendler Corporation

ABSTRACT: In any applications of rotating equipment, it is common for an engineer to try to minimize the response of a structure with a rotating imbalance. This paper demonstrates how to perform this minimization using MSC/NASTRAN. A practical example problem is used. This sample minimizes the response at the driver's seat of a car model with a wheel out-of-balance. The problem will begin by demonstrating how to perform frequency response analysis of the car model with a rotating imbalance, followed by dynamic sensitivity of the response, followed by minimization of the response by tuning the dampers (shock absorbers) and springs.

During the process, special features in MSC/NASTRAN will be used to assist in understanding the dynamic problem and in determining the best approach to minimizing the response.

USING DESIGN SENSITIVITY FOR STATISTICAL RESPONSE ANALYSIS (Acrobat 690KB) #2793, 19 pgs.
Ken Blakely -- The MacNeal-Schwendler Corporation

ABSTRACT: Statistical response analysis computes the statistical distribution of responses, given the distribution of design variable values. Variation in design variable values can result from manufacturing tolerances, and it can also be attributed to a level of uncertainty about the finite element input. Statistical distributions discussed herein are the standard deviation and variance.

Statistical response analysis can be accomplished in MSC/NASTRAN by using SOL 200 and DMAP alters in Version 67.5. This paper describes the theory, alters, and examples.

Optimization and Nonlinear

ADJOINT SENSITIVITY ANALYSIS IN MSC/NASTRAN, (Acrobat 322KB) #2897, 12pgs.
Erwin H. Johnson--The MSC.Software Corporation

ABSTRACT

BOSS-QUATRO AND MSC/PATRAN: A NEW GENERATION OF OPEN-ARCHITECTURE MULTIDISCIPLINARY OPTIMIZATION SOFTWARE, (Acrobat 215KB) #2497, 16pgs.
Patrick Morelle--SAMTECH s.a.John Klintworth--MSC Ltd.

ABSTRACT: Today's design in industry is in fact a combination of techniques whose primary goal is to understand the model's behavior. The next step is then to analyze the performance of the model using numerical simulation. Various sequences of trade-off, parametric analysis, sensitivity analysis, are then performed in order to formulate the final optimization problem properly. A basic feature of many design problems is their multi-disciplinary nature. As a result, more and more physical phenomena are being modeled and taken into account in the design problem formulation. This has required the use of more disparate and heterogeneous analysis and simulation software.

For those reasons, Samtech s.a. has developed an open design and optimization architecture: BOSS-QUATTRO. This new software has been applied with success in multi-disciplinary (e.g. fluid/structure) analysis and optimization as well as in parametric studies and Monte Carlo analysis. In particular, a very powerful system has been built by linking the BOSS-QUATTRO system to the MSC/PATRAN environment, providing new capabilities for multi-disciplinary optimization by taking advantage of MSC/PATRAN's existing links to multiple analysis codes.

The BOSS-QUATTRO environment is designed as an application manager: it includes existing analysis chains in arbitrary loops and sequences, and provides new capabilities like parametric studies, Monte-Carlo simulation, sensitivity analysis or optimisation. BOSS-QUATTRO is linked to application programs in a standard way through drivers. This open architecture means that the system is able to exchange information with present and future commercial products as well as with in-house codes. For example, drivers exist for popular commercial software MSC/PATRAN, MSC/NASTRAN, SAMCEF, PRO-ENGINEER and CATIA. In addition, any application using a text file for input and output can be linked through a flexible "neutral" driver.

Within the present paper, two applications developed in the context of a BRITE/EURAM project (MODSYSS, CT94-0590) are presented. The first takes advantage of links between MSC/PATRAN and several analysis codes to perform multidisciplinary analyses on a component. The second links a parametric CAD system to an analysis code to allow full three-dimensional shape optimization. These examples demonstrate the ability to link together disparate commercial software systems to perform effective design optimization.

DETERMINISTIC DESIGN, RELIABILITY-BASED DESIGN AND ROBUST DESIGN, (Acrobat 78KB) #2597, 11pgs.
Wei Wang and Justin (Y.T.) Wu--Southwest Research Institute
Robert V. Lust--General Motors Research & Development Center

ABSTRACT

NEXT GENERATION STRUCTURAL OPTIMIZATION TODAY, (Acrobat 1.1MB) #2697, 14pgs., color
Craig S. Collier, P.E., Mark Pickenheim, and Phil W. Yarrington--Collier Research & Development Corporation

ABSTRACT: Characteristics of a next generation software product are presented for a coupled MSC/NASTRAN FEA and structural optimization system. These characteristics include methods for automated structural analysis and optimization such as a statistical approach for determining 'design-to' loads and analytical/numerical 'zooming' for detailed global to local response. Software characteristics include a collection of standard panel and beam concepts, and an object oriented approach to strength and stability failure analyses. These features are provided in a multiproject, multiuser, secure database environment where the Internet standard Virtual Reality Modeling Language (VRML) is used for visual interpretation of results.

NONLINEAR STRENGTH AND STABILITY ANALYSIS OF A LANDING GEAR COMPONENT, (Acrobat 1.17MB) #2797, 15pgs.
Andrew Mera--The Boeing Company

ABSTRACT: The reserve strength of an aircraft landing gear beam is evaluated, using an MSC/NASTRAN finite element model. The load is incremented until positive margins of safety can be demonstrated for the various design criteria considered. Differences in simulated behavior are identified when the model formulation includes initial stress stiffening, geometric and material nonlinearity, and instability. The sensitivity of the results is investigated to variations in end restraints and to geometric imperfections.

p-elements

THE APPLICATION OF INTERFACE ELEMENTS TO DISSIMILAR MESHES IN GLOBAL/LOCAL ANALYSIS (Acrobat 704KB) 1996, 16 pgs. John E. Schiermeier--The MacNeal-Schwendler Corporation Jerrold M. Housner--NASA Langley Research Center Jonathan B. Ransom--NASA Langley Research Center Mohammad A. Aminpour--Applied Research Associates, Inc. W. Jefferson Stroud--NASA Langley Research Center

ABSTRACT

PCL

CFD DATA TRANSFER TO STRUCTURAL ANALYSIS (Acrobat 2.9MB) 1996, 19 pgs. W. Scott Taylor--Sverdrup Technology, Inc.

ABSTRACT

CUSTOMIZATION OF WING ANALYSIS (Acrobat 33K) #3698, 7 pgs.
Wang Linjiang--Nanjing University of Aeronautics and Astronautics, PR China
Matthias Haupt--TU Braunschweig, Germany

ABSTRACT: This article is concerned about the customization of creating a FEM model of a wing structure. The row and column method is used to number the structure parts(ribs, spars, skins), then the property parameters of all parts can be respectively inputted using the spreadsheet in which data can be inputted easily and correctly. A PCL(MSC/PATRAN Command Language under MSC/PATRAN 6.0) code is developed for the customization from constructing airfoil curves to creating the entire wing FEM model. A zigzag wing is demonstrated to verify the code. At last a VFW614 wing is analyzed from creating airfoil curves to the show of stresses that are calculated using MSC/NASTRAN 68. The results shows that this customization is very effective and efficient, it makes such a difficult work of creating a wing FEN model become much easier. This method can likewise be used to fuselage and other complicated structures.

ENVELOPING RESULTS OF MULTIPLE LOAD CASES (Acrobat 65K) #3498, 10 pgs.
Victor Genberg--Eastman Kodak Company
Justin Vianese--The MacNeal-Schwendler Corporation

ABSTRACT: Many structures such as those used in the aerospace and the automotive industry are subjected to multiple load conditions. Software has been developed to scale, combine, and sort stresses, forces, and displacements from a few unit load cases. The procedure saves creating and running many load cases, requires much less plotting, and prevents errors of omission. A launch load event of 128 combinations can be analyzed from 7 unit load cases combined into a single plot. This technology is now available as MSC/PATRAN shareware.

AN INTEGRATED COMPUTER AIDED ENGINEERING TOOL FOR AIRCRAFT TRANSPARENCY DESIGN ANALYTICAL DESIGN PACKAGE--ADP (Acrobat 4.2MB) 1996, 25 pgs. J.E. Wuerer--The MacNeal-Schwendler Corporation M. Gran--Wright-Patterson AFB T.W. Held--University of Dayton Research Institute

ABSTRACT

ADP is a customized integration of analysis codes, CAE software and material information databases. The primary CAE integration tool for the ADP is MSC/PATRAN, a commercial-off-the- shelf (COTS) software tool. The open architecture of MSC/PATRAN allows customized installations with different application modules for specific site requirements. Integration of material databases allows the engineer to select a material and those material properties are automatically input into the relevant analysis code. The ADP materials database supports two independent schemas: (1) CAE Design Properties and (2) Processing and Test Data.

The design of the ADP places major emphasis on the seamless integration of CAE and analysis modules with a single intuitive graphical interface. This tool has been designed to serve and be used by an entire project team, i.e., analysts, designers, materials experts and managers. The final version of the software was delivered to the Air Force in June 1995. The Analytical Design Package (ADP) is intended to facilitate technology transfer to industry. The analysis system is capable of a wide range of design and manufacturing applications.

INTEGRATION OF MSC/PATRAN WITH SANDIA NATIONAL LABORATORY'S EXODUS II DATABASE SYSTEM (Acrobat 640KB) 1996, 19 pgs. Ken Walker--The MacNeal-Schwendler Corporation

ABSTRACT

INTERFACING MSC/PATRAN WITH EXTERNAL SURFACE MESHERS (Acrobat 256KB) 1996, 7 pgs. R. Shanmugasundaram--Computer Sciences Corporation Jamshid Samareh--Computer Sciences Corporation

ABSTRACT

USING MSC/PATRAN FOR PRE- AND POSTPROCESSING FOR SPECIALIZED FEM CODES WHICH ARE NOT IN THE STANDARD MSC/PATRAN LIBRARY (Acrobat 448KB) 1996, 19 pgs. Daniel D. Jensen--University of the Pacific

ABSTRACT: MSC/PATRAN is commonly used in industry and academia as a pre- and postprocessor for commercially available FEM codes like MSC/NASTRAN, ANSYS, ABAQUS and others. However, a significant amount of analysis and research continues to be done with specialized FEM codes which do not have built in interfaces to MSC/PATRAN or any other widely available pre- or post processor. The present work provides a basic interface which allows models built in PATRAN access to the data necessary to build standard input decks for specialized FEM codes which are not supported by PATRAN. In addition, details are given for importing the results from analysis done with a specialized code back into PATRAN for visualization. An example is given which shows the ease of use of the interface. The interface presented provides an extremely expedient solution to the alternative of writing your own pre-and postprocessor.

PC Products

INTEGRATED FEM/FEA ON POWER MAC (Acrobat 326KB) #4595, 9 pgs.
Gert Lundgren--LAPCAD Engineering: ABSTRACT: LAPCAD Engineering introduces LapFEA, a logical union of LapCAD and MSC/pal 2. The model is created in LapFEA, complete with connectivities, properties and loads. Then the analysis is executed with icons in the Solver tool pallet. Post-processing and documentation with a word processor is completed from within LapCAD.
MSC/NASTRAN FOR WINDOWS: THE POWER OF MSC/NASTRAN COUPLED WITH THE EASE OF USE OF WINDOWS (Acrobat 654KB) #4695, 10 pgs.
Ken Blakely--MacNeal-Schwendler Corporation
Cliff Brown--MacNeal-Schwendler Corporation
Brian Casey--MacNeal-Schwendler Corporation
Wai Ho--MacNeal-Schwendler Corporation
Son Giang--MacNeal-Schwendler Corporation
Mark Kenyon--MacNeal-Schwendler Corporation
John Muskivitch--MacNeal-Schwendler Corporation
John Saunders--MacNeal-Schwendler Corporation
Grant Sitton--MacNeal-Schwendler Corporation
Richard Taylor--MacNeal-Schwendler Corporation: ABSTRACT: This paper presents an overview of MSC/NASTRAN for Windows. The product integrates modeling, analysis, and postprocessing, all within the familiar interface of Microsoft Windows 3.1. This paper focuses on the philosophy, features, and performance of the product.
MULTI DISCIPLINARY ANALYSIS IN MSC/NASTRAN WITH FEMAP (Acrobat 1.29MB) #4495, 15 pgs.
Mark A. Sherman--Enterprise Software Products, Inc.

ABSTRACT:

Pre- and Postprocessing

A COMPARISON OF THREE ADAPTIVE REMESHING TECHNIQUES (Acrobat 742KB) #4693, 16 pgs.
Joseph L. Walsh -- FEGS, Incorporated

ABSTRACT:

EXPOSING THE MYTHS OF DESIGN TO ANALYSIS DATA EXCHANGE (Acrobat 673KB) #6093, 14 pgs.
Joseph L. Walsh -- FEGS, Incorporated

ABSTRACT: Design/Analysis integration is a major issue for most companies performing finite element analysis. This paper will outline some of the underlying issues and difficulties along with exposing the deficiencies of several attempts at Design/Analysis integration. This paper will also outline the approach and capabilities of data exchange based on IGES using MSC/XLfromCAD and FAM along with data exchange based on STEP.

"GEOMETRIC" FE ANALYSIS WITH MSC/XLPLUS (Acrobat 937KB) #4493, 11 pgs.
Celso A. Barcelos -- Aries Technology

ABSTRACT:

JOINING TETRAHEDRA TO HEXAHEDRA (Acrobat 416KB) #4593, 10 pgs.
Alok Mahajan -- Optimal CAE, Inc

ABSTRACT:

SHAPE FUNCTION INTERPOLATION OF 2D AND 3D FINITE ELEMENT RESULTS (Acrobat 679KB) #4793, 16 pgs.
Victor Genberg -- Commercial & Government Systems, Eastman Kodak Company

ABSTRACT:

1) Obtaining displacement boundary conditions on finer resolution breakout models
2) Optical ray tracing on deformed mirror surfaces
3) Placing temperatures from a coarse thermal model on to a finer structural model.

TOPOLOGY BASED ANALYSIS MODELING AND PARAMETER DRIVEN ANALYSIS MODELS IN FEGS FAM 3.0 (Acrobat 455KB) #6193, 11 pgs.
Joseph L. Walsh -- FEGS, Incorporated

ABSTRACT: Finite element analysis is being used more and more today to evaluate design alternatives and drive design decisions. The ability to quickly modify an Analysis Model based on design geometry parameters requires a Topology Based Analysis Model and may also require Parameter Driven Analysis Models. This paper will discuss the implementation of Topology Based Analysis Modeling in FEGS FAM3.O Modeling System allowing for multiple geometric representations and assignment of analysis attributes to the topological entities. This paper will also discuss the application of parameter symbols and macros in FAM3.O to achieve Parameter Driven Analysis Models along with user definable extensions to FAM3.O.

VARYING PRESSURE DISTRIBUTION OVER A GROUP OF ELEMENTS USING MSC/XL (Acrobat 436KB) #6293, 15 pgs.
Pathuri Rama Murthy -- WIPRO Infotech Limited

ABSTRACT: A commonly encountered problem in FEA is applying pressures of linear or non-linear nature, over a group of elements. This paper presents a simple but effective way of specifying these kind of pressures using MSC/XL.

Process Strategies

HP AND MSC COLLABORATION ON MSC/SUPERMODEL, (Acrobat 114KB) #0697, 6pgs.
Harvey Ivory--The MSC.Software Corporation
Andrew Page--Hewlett-Packard

ABSTRACT:

MSC AEROSPACE SOLUTIONS: OPTIMIZING THE DESIGN-TO-CERTIFICATION PROCESS, (Acrobat 1.37MB) #0197, 12pgs.
Ken Blakely--The MSC.Software Corporation

ABSTRACT:

MSC PRODUCT UPDATE, (Acrobat 1.32MB) #0597, 14pgs., color
Mark Kenyon, Bob Jones, Greg Sikes and Alan Caserio--The MSC.Software Corporation

ABSTRACT:

PRODUCT SIMULATION INTEGRATION FOR STRUCTURES, (Acrobat 30KB) #0397, 6pgs.
H. Martin Prather, Jr.--The Boeing Commercial Airplane Group (BCAG)
Raymond A. Amador--The MSC.Software Corporation

ABSTRACT: The Product Simulation Integration (PSI) Structures project is under way in BCAG to reduce costs and cycle time in the design, analysis, and support of commercial airplanes. The objective of the PSI project is to define and enhance the processes, methods, and tools to integrate structural product simulation with structural product definition. This includes automated engineering analysis as an integral component of the product definition. Subprojects have been defined and we are working selected topics toward accomplishing the objectives of the PSI for BCAG Structures. Formalized integration activities have also been identified to support the PSI subprojects through their technology life cycle.

REDEFINING THE PROCESS OF AIRFRAME FINITE ELEMENT MODEL DEVELOPMENT USING MSC/SUPERMODEL, (Acrobat 1.37MB) #0497, 15pgs., color
Michael Farley-- Raytheon E-Systems Waco

ABSTRACT: To develop, in less than one year, an MSC/NASTRAN 747SP finite element model from scratch to support the SOFIA (Stratospheric Observatory for Infrared Astronomy) program is an effort requiring significant planning. Model development is facilitated by dividing the airframe structure into submodels enabling parallel development of each submodel within separate MSC/PATRAN databases. Directing this effort requires configuration control and file management to maintain the overall pedigree of the model, which includes section properties, history files, drawings used and assumptions made. This paper discusses how MSC/SuperModel is being used to redefine airframe finite element modeling at Raytheon E-Systems Waco.

STRUCTURAL ANALYSIS FOR THE 21^ST CENTURY, (Acrobat 1.37MB) #0297, 14pgs.
Brian P. Oldfield--British Aerospace

ABSTRACT:

Shape Optimization

AN ALTERNATIVE APPROACH FOR IMPROVING THE ACCURACY OF SEMI-ANALYTIC DESIGN SENSITIVITIES IN SHAPE OPTIMIZATION (Acrobat 510KB) #3993, 18 pgs.
GaoWen Ye -- The MacNeal-Schwendler Corporation
Shenghua Zhang -- The MacNeal-Schwendler Corporation
David N Herting -- The MacNeal-Schwendler Corporation

ABSTRACT: The semi-analytic method has been adopted for shape sensitivity calculations because it does not require special code for analytic derivatives of element matrices. However, this method may have serious accuracy problems for which several approaches have been proposed. These approaches, however, are either lack of generality or difficult to be integrated with a general-purpose FEM package. Here, an effective approach to the problem has been developed in which an iterative algorithm used. It not only improves the accuracy but also provides error estimators so as to ensure the quality of calculated sensitivities. In addition, it can be easily integrated with MSC/NASTRAN In this paper, the basic idea of the approach is first described. Then, a general algorithm based on the approach is given. Finally, its effectiveness is shown through numerical results.

COMPUTER AIDED SHAPE OPTIMIZATION FOR ENGINEERING DESIGN WITH MSC/NASTRAN (Acrobat 566KB) #3793, 20 pgs.
Shenghua Zhang -- The MacNeal-Schwendler Corporation

ABSTRACT:

FORMULATION OF PARAMETER-BASED SHAPE SENSITIVITIES FROM FREE-FIELD SIZE SENSITIVITIES (Acrobat 911KB) #3893, 20 pgs.
Afshin Mikaili -- Iowa State University
James Bernard -- Iowa State University

ABSTRACT:

Space

MODAL TEST CORRELATION AND ERROR LOCALIZATION FOR FINITE ELEMENT MODELS OF SPACECRAFT STRUCTURES(Acrobat 390K) #1599, 18 pgs. J. Lopez-Diez, V. Marco-Gomez, and C.Cuerno-Rejado--Universidad Politecnica de Madrid, E.T.S.I. Aeronauticos Pedro Luengo--Construcciones Aeronáuticas S.A.(CASA), Spain

ABSTRACT: This paper describes the use of some tools for matching modal test data and
finite element model results. Different reduction/expansion techniques have been implemented in order to become analytical and experimental models size compatible. MAC, NCO and SCO coefficients allow quantifying the degree of correlation between analysis and test results. An error localisation technique based on Mass and Stiffness Baruch´s method updating has been implemented. The analytical model of the structure is updated on the basis of experimental data using a direct updating method and new stiffness and mass matrices are generated. The error vector technique assigns errors calculated on stiffness and mass matrices to the different elements of the model.
Thence, they are plotted on the mesh, and its colour denotes the amount of error. The process of error interpretation is simplified and physical meaning can be deduced. Modes measured in tests are expanded and plotted and visual comparison of mode shapes (analytical determined and experimentally measured) is performed. The influences of the boundary conditions simulation and sensor location are investigated.
Algorithms to calculate different correlation parameters, reduction/expansion methods and tools for error location have been implemented in DMAP. Therefore, they can be included in most of the finite element models developed in MSC/NASTRAN. The visualisation on the model results useful in order to identify the major modelling error regions. A study on a flat plate is used as benchmark.
Finally, results of the application to the Polar Platform Panel model are showed.

MODEL VALIDATION AND TESTING OF INTERNATIONAL SPACE STATION STRUCTURES USING MSC/NASTRAN
(Acrobat 358K) #1399, 16 pgs.
Tarun Ghosh--Boeing North American, Inc.

ABSTRACT: In order to perform analysis to support the design of the International Space Station, mathematical models of the components were generated in the form of finite element models. Test verification of these models is required before the components can be certified for launch. Modal testing is one of the several tests performed on the components for certification. The purpose of the modal tests is to show that the mathematical models have the same dynamic characteristics as the physical models. Namely, that they have the same frequencies, modeshapes and mass properties. As part of the pre-test analysis, fixtures and flexures simulating the boundary conditions need to be validated. When the test article differs from the flight hardware, the actual flight hardware also has to be qualified. In addition, shaker locations for application of forces and accelerometer locations for the collection of response data need to be identified. It is important to identify the target modes, which must satisfy the comparison criteria for frequencies, modeshapes and mass properties. As part of the post-test analysis, the test modeshapes are used to validate the mathematical models. For better correlation with test data, the mathematical model may need to be updated. The purpose of this paper is to show how efficiently MSC/NASTRAN can be used in modal testing and model validation and updating. Features developed and lessons learnt are described in this paper for their general usefulness.

SPACECRAFT STRUCTURAL ANALYSIS TODAY AND YESTERDAY(Acrobat 650K) #1299, 15 pgs.
Charles Gamblin, PE-Teledyne Brown Engineering

ABSTRACT:This paper presents a present-day MSC NASTRAN/PATRAN * static/dynamic FEM of the first Saturn I First Stage Booster (1962). This historic Saturn I launch vehicle was successfully flown nineteen times with one manned launch mission (Apollo 7) an 163 earth orbit practice run for the more historic Apollo 11 moon landing thirty years ago in July 1969. The Saturn I FEM shown is a gross static force and dynamic displacement model with limited stress accuracy. More detailed substructured models would be required for a complete stress analysis, which is the standard operating procedure by today’s structural analysis methods.
In the yesteryear, the original static analysis approach involved the judicious application of free body cuts through the clustered tank booster assembly to expose the indeterminate internal reaction forces. Each tank was considered as a “finite element” in the stack-up of structural stiffness (matrix) components. Applying the laws of static equilibrium, the formation of the redundant equations resulted in a 12x12 stiffness matrix for solution. This paper shows examples of the original redundant equation formulation and the computer analysis output results in free body format.

TRANSIENT ANALYSIS OF THERMAL PROTECTION SYSTEM FOR X-33 VEHICLE USING MSC/NASTRAN, (Acrobat 619KB) #1897, 10 pgs.
H. Miura, M. Chargin, J. Bowles and T. Tam--NASA Ames Research Center
Dan Chu and Mike Chainyk--MacNeal Schwendler Corporation

ABSTRACT: X-33 is an advanced technology demonstrator aircraft for the reusable launch vehicle (RLV) design. The thermal protection system (TPS) for the X-33 is composed of complex layers of materials to protect internal components, while withstanding severe external temperatures induced by aerodynamic heating during high speed flight. It also serves as the vehicle aeroshell in some regions using a stand-off design. MSC/NASTRAN thermal analysis capability was used to predict transient temperature distribution (within the TPS) throughout a mission, from launch through the cool-off period after landing.

In this paper, a typical analysis model, representing a point on the aircraft where the liquid oxygen tank is closest to the outer mold line, is described. The maximum temperature difference between the outer mold line and the internal surface of the liquid oxygen tank can exceed 1500°F. One dimensional thermal models are used to select the materials and determine the thickness of each layer for minimum weight while insuring that all materials remain within the allowable temperature range. The purpose of working with three dimensional (3D) comprehensive models using MSC/NASTRAN is to assess the 3D radiation effects and the thermal conduction heat shorts of the support fixtures.

UPDATED DYNAMIC ANALYSIS METHODS FOR THE SPACE SHUTTLE SOLID ROCKET MOTOR
(Acrobat 260K) #1499, 9 pgs.
Christopher C. Flanigan--Quartus Engineering Incorporated
Dale Nielsen--Cordant Technologies,Thiokol Corporation

ABSTRACT:The RSRM dynamic models and analysis procedures were recently updated to take advantage of improvements in computer hardware and software performance. Many new and enhanced features of MSC/NASTRAN were exercised including sparse matrix routines, Lanczos eigensolver, enhanced superelements, and residual vectors. The models and analysis procedures were migrated to Windows NT workstations to take advantage of the price/performance ratio of these platforms.
The methods upgrade for the RSRM dynamic models has significantly improved ease of use,
dramatically reduced computer run times, and minimized the need for custom codes. Important features of the upgraded methods will be presented in the paper. Computer run times using NT workstations will be compared to original analyses performed on Cray mainframes.

Spacecraft

APPROXIMATE DYNAMIC MODEL SENSITIVITY ANALYSIS FOR LARGE, COMPLEX SPACE STRUCTURES (Acrobat 416KB) 1996, 20 pgs. Timothy S. West--McDonnell Douglas Aerospace

ABSTRACT

DEVELOPMENT OF SPACE STATION LOADS DUE TO ON-ORBIT THERMAL ENVIRONMENTS (Acrobat 288KB) 1996, 16 pgs.
Charles A. Jacobson, Jr--McDonnell Douglas Aerospace
Robert A. Rudd--McDonnell Douglas Aerospace

ABSTRACT

Stress Analysis

AUTOMATED STRESS ANALYSIS - REDUCING STRESS ANALYSIS TIME BY AN ORDER OF MAGNITUDE (Acrobat 296KB) #4195, 6 pgs. John C. Lambert--United Technologies Hamilton Standard Division Brent J. Merritt--United Technologies Hamilton Standard Division
CLOSED-FORM STATIC ANALYSIS WITH INERTIA RELIEF AND DISPLACEMENT-DEPENDENT LOADS USING A MSC/NASTRAN DMAP ALTER (Acrobat 686KB) #3195, 14 pgs.
Alan R. Barnett--Analex Corporation
Timothy W. Widrick--Analex Corporation
Damian R. Ludwiczak--National Aeronautics and Space Administration
DMAP ALTERS TO ADD DIFFERENTIAL STIFFNESS AND FOLLOWER FORCE MATRICES TO MSC/NASTRAN LINEAR SOLUTIONS (Acrobat 341KB) #3395, 9 pgs.
David F. Bella--MacNeal-Schwendler Corporation
DYNAMIC ANALYSIS OF R.C.C. CHIMNEYS (Acrobat 787KB) #3495, 14 pgs. M. Shivaji--A.P.S.E. Board V.S.N. Raju--A.P.S.E. Board
THE EFFICIENT CALCULATION OF STRESS CONCENTRATION FACTORS (Acrobat 891KB) #3094, 15 pgs.
D. L. Dewhirst -- Ford Motor Co.
Wai Ho -- The MacNeal-Schwendler Corporation: ABSTRACT: Certain stress concentration problems recur often in the design of torque-carrying shafts. We desired to construct a set of tables similar to those in Peterson's Stress Concentration Handbook to permit rapid manual preliminary sizing of these shafts. Because a large number of parameters were involved, the efficiency of the modeling process was an issue. This study compares a variety of modeling techniques with emphasis on the p-adaptive approach available in MSC/NASTRAN, version 68.
ELASTIC-PLASTIC ANALYSIS AROUND A CIRCULAR HOLE STRESS CONCENTRATION (Acrobat 752KB) #2894, 20 pgs.
Robert P. Thacker, Jr. -- Boeing Computer Support Services
EVALUATION OF MSC'S PARABOLIC TETRAHEDRON FINITE ELEMENT (Acrobat 571KB) #2994, 16 pgs.
Kevin E. Arden -- Newport News Shipbuilding: ABSTRACT: Automatic mesh generators, based on the solid model geometry, will only produce tetrahedron elements. Solids based modeling techniques allow for efficient and easy creation of solid element models. This paper evaluates the accuracy of the element by comparing closed form solutions and actual test data to solutions calculated using MSC/NASTRAN.

The test data resulted from a recent design experience where solid modeling capabilities were beneficial. This design experience is presented along with the test validation of the finite element results.

The modeler used herein is 1-DEAS VI.l provided by SDRC.

The opinions of this paper are the author's and do not necessarily represent the opinions of Newport News Shipbuilding.

ABSTRACT: Cut-outs in pressurized aircraft fuselages are very sensitive to fatigue. This explains the need for a design tool to enable the designer to perform a comprehensive design of these "difficult" structures. A menu-driven, highly interactive system for the design of the reinforcement around a cut-out in a pressurized fuselage is presented. The design system is set up in such a way that maximum use is made of the combination of MSC/NASTRAN and MSC/PATRAN. There are six basic options offered by the system: 1) fast, easy initial model generation; 2) fully interactive, user-friendly model editing; 3) preparation for both geometrically linear and geometrically non-linear finite element calculations; 4) preparation for a sensitivity analysis and graphical display of the results of such an analysis; 5) carrying out "what-if" studies; 6) preparing and performing a design optimization.

The system is set up as a special-purpose design tool. This makes a considerable improvement in the design process, because the time needed for the modelling of the complex structure is greatly reduced. The design system is based on the pre- and post-processor MSC/PATRAN. The necessary software is written almost entirely in MSC/PATRAN Command Language (PCL) which implies that the generated code can be run "inside" MSC/PATRAN. Maximum use is made of the graphical capability of this software package. The finite element calculations, including sensitivity analysis and optimization, are performed with MSC/NASTRAN.

SASSI - STRUCTURAL ANALYSIS SOFTWARE SYSTEMS INTERFACE (Acrobat 1.57MB) #4295, 12 pgs.
Lee Abbuhl--Boeing Computer Services
Viswa Padma_nabhan--Boeing Computer Services

ABSTRACT: SASSI contains a set of tools for structural engineering analysis in a distributed workstation environment. These tools provide 1) access to a host of engineering applications software through a single command 'SASSI' entered in a workstation window. Analysis data post-processing, network tasks, plotters and printers, and additional system and analysis tools are available and accessed by a set of pop-up menus and dialog boxes in the menu. 2) Data transfers between the various applications are very efficient in SASSI. 3) An interactive menu interface provides transparent access to engineering computing tasks and applications that enhances the productivity of stress engineers. Some of these will be illustrated by examples using MSC/NASTRAN.

SELF-EXCITED OSCILLATION OF A 165 FOOT WATER TOWER (Acrobat 957KB) #3295, 21 pgs.
Louis J. Pulgrano--E. I.. duPont de Nemours and Company
Steven G. Masters--E. I.. duPont de Nemours and Company

ABSTRACT: When a new 165 foot high water tank was being filled for the first time, a large amplitude oscillation of the entire structure occurred and forced an immediate shutdown of the filling process. Analysis of the problem, using a combination of math modeling and experimental measurements, revealed the cause to be an unstable coupled fluid/structural response that was being driven by the incoming water. Design modifications were needed to eliminate the coupling and allow the tank to be put into service.

Superelements

DATA RECOVERY AND MODEL REDUCTION METHODS FOR LARGE STRUCTURES (Acrobat 761KB) #2393, 16 pgs.
Hyoung M. Kim -- McDonnell Douglas Aerospace - Space Systems
Theodore J. Bartkowicz -- McDonnell Douglas Aerospace - Space Systems
David A. VanHorn -- McDonnell Douglas Aerospace - Space Systems

ABSTRACT: This paper demonstrates important factors for the application of mode-superposition methods and component mode synthesis to transient response analyses of large structures. A theoretical review is presented and numerical results are evaluated for three case studies. Data recovery techniques based on the mode-superposition method are evaluated with respect to different types of force input, model reduction, model size, and computational resources. Cutoff frequency selection at the component- and system-level of component mode synthesis is discussed for accurate dynamic response calculations. This paper not only shows the theoretical differences between different data recovery methods, but also provides physical insights at each computational stage.

DMAP ALTERS TO APPLY MODAL DAMPING AND OBTAIN DYNAMIC LOADING OUTPUT FOR SUPERELEMENTS (Acrobat 561KB) #2493, 16 pgs.
Ted L. Rose -- The MacNeal-Schwendler Corporation

ABSTRACT: A pair of DMAP alters are presented for use in the structured superelement dynamic solutions in MSC/NASTRAN Version 67.5. The first DMAP alter allows the entry of a "modal damping" matrix for superelements by using TABDMP1 entries and the frequencies of the calculated component modes. This allows the use of damping results obtained from dynamic testing of individual components in an assembly analysis.

The second alter implements the calculation and output (including plots and PSD) of the applied dynamic loads on superelements. This provides the user with a tool to verify that dynamic loads applied to superelements were entered properly.

DMAP ALTERS FOR NONLINEAR CRAIG-BAMPTON COMPONENT MODAL SYNTHESIS (Acrobat 1.43MB) #2593, 30 pgs.
Herand Bedrossian -- Rockwell International Corp.
Ted Rose -- The MacNeal-Schwendler Corporation

ABSTRACT: A set of DMAP (Direct Matrix Abstraction Program) alters for MSC/NASTRAN have been developed for generating reduced matrices for nonlinear structures using the Craig-Bampton [1] method. These DMAP alters are currently being used in conjunction with the standard MSC/NASTRAN component modal synthesis approach to create a system model for coupled loads analysis of Space Station Freedom (SSF) on-orbit configurations. Nonlinear Craig-Bampton models of the Photo Voltaic (PV) arrays are created and combined with the linear Craig-Bampton models of the various other SSF components using the external superelement approach. In addition, a modal selection DMAP Alter is provided. This alter is used in combination with an external FORTRAN program to select a reduced set of component modes based on the modal strain energy criteria. The procedure is illustrated with an example problem.

IMPLEMENTATION OF THE BLOCK-KRYLOV BOUNDARY FLEXIBILITY METHOD OF COMPONENT SYNTHESIS (Acrobat 917KB) #2693, 20 pgs.
Kelly S. Carney -- National Aeronautics and Space Administration
Ayman A. Abdallah -- Analex Corporation
Arthur A. Hucklebridge -- Case Western Reserve University

ABSTRACT: A method of dynamic substructuring is presented which utilizes a set of static Ritz vectors as a replacement for normal eigenvectors in component mode synthesis. This set of Ritz vectors is generated in a recurrence relationship, which has the form of a block-Krylov subspace. The initial seed to the recurrence algorithm is based on the boundary flexibility vectors of the component. This algorithm is not load-dependent, is applicable to both fixed and free-interface boundary components, and results in a general component model appropriate for any type of dynamic analysis. This methodology has been implemented in the MSC/NASTRAN normal modes solution sequence using DMAP. The accuracy is found to be comparable to that of component synthesis based upon normal modes. The block-Krylov recurrence algorithm is a series of static solutions and so requires significantly less computation than solving the normal eigenspace problem.

SuperModel & PATRAN

ESTABLISHING NEW METHODOLOGIES WITH MSC SOFTWARE PRODUCTS TO DEVELOP A 747SP FINITE ELEMENT MODEL FOR FAA CERTIFICATION OF AIRFRAME DESIGN MODIFICATION (Acrobat 1.9 MB) #0499, 14 pgs. Michael Farley--Raytheon System Company

ABSTRACT: Raytheon Systems Company Waco has developed a MSC/NASTRAN finite element model from drawings of the Boeing 747SP in support of the SOFIA program. SOFIA (Stratospheric Observatory For Infrared Astronomy) is an airborne observatory housing a 2.5 meter infrared telescope (the largest ever airborne). The SOFIA airborne observatory will take a team of NASA scientists, engineers, and educators above 41,000 feet placing the aircraft above 99% of the earth's obscuring water vapor and providing a view of the universe superior to any earth bound observatory. The 747SP finite element model is playing a significant role in the structural substantiation of the design modifications to the 747SP. There are three phases of finite element model development: the baseline model representing the baseline configuration of the Boeing 747SP, the section 46 design model characterizing all of the design changes reflected in the SOFIA design modification, and the certification model with the final SOFIA design modification incorporated into the full 747SP finite element model. These models are MSC/PATRAN databases defined within MSC/SuperModel. MSC/SuperModel has been used to maintain configuration control of the MSC/PATRAN databases and to establish the pedigree of the model by maintaining the history of the model assembly. Throughout the certification process CAE tools and methods have significantly enhanced productivity and have been used to provide an integrated method of data management and analysis. This paper illustrates the finite element process from airframe modification design to the design certification process, and how the Methods & Finite Element Group at Raytheon Waco has utilized MSC software products to enhance the certification process.

Test-Analysis Correlation

DRIVESHAFT SEAL BOOT FINITE ELEMENT ANALYSIS (Acrobat 98K) #3998, 10 pgs.
Leandro Jaskulski, Leônidas Coutinho, César Franck, and Rubens Gehlen--ATH - Albarus Transmissões Homocinéticas ltda.

ABSTRACT: This study registers a finite element analysis of a seal boot used in constant velocity driveshafts, that was performed in the MSC/NASTRAN software for Windows NT 4.0 in a Personal Computer. By this analysis the structure’s behavior was studied in its work life before construction of the actual prototype.
Analysis was made in existing seal rubber boot, showing good accuracy level when compared with actual part displacement test results. At first, critical joint motions were selected to identify the constrains and symmetric plans. The hyperelastic material was approached to an elastic material in this first step to apply in a plate element model of the part. Then the results of general part behavior, like displacements, and contacts were examined and contrasted with laboratory test reports of the real part.
Prototype development time can be saved in the design phase since the part can be improved by this theoretical prediction tool. Failure points can be predicted by the analysis saving resources such as developing production tools, making prototypes and testing them to finally detect the items that have to be improved.

HIGH CONFIDENCE PERFORMANCE PREDICTION TO IMPROVE THE VEHICLE DEVELOPMENT PROCESS (Acrobat 32KB) 1996, 13 pgs.
N. Purushothaman--Ford Motor Company M. Menon--Ford Motor Company
P. Randle--Ford Motor Company
C. Rivard--Ford Motor Company
H. Chen--Ford Motor Company

ABSTRACT: Ford is increasingly using CAE tools to speed up the product development process and replace hardware prototypes while bringing new products to market. The use of an analytical prototype allows performance to be predicted in advance of hardware proveout. Many design iterations can be performed, thus producing a world class vehicle. The accuracy of these predictions for a given attribute, and how the resultant design recommendations are integrated with other attributes has remained a major issue for the CAE community. During the recent development of a new vehicle all CAE disciplines (Safety, NVH, Durability, Vehicle Dynamics, etc.) were successfully combined to "sign-off" a design based entirely on CAE.

This paper explains how the Durability and NVH CAE attributes employed MSC/NASTRAN to produce high confidence results as part of an integrated process which allowed the vehicle to be verified for the Global and local performance at approximately 3 years to job 1.

MATCHING FREQUENCY RESPONSE TEST DATA WITH MSC/NASTRAN (Acrobat 490KB) #1794, 12 pgs.
Ken Blakely -- The MacNeal-Schwendler Corporation

ABSTRACT: This paper describes the use of MSC/NASTRAN for matching frequency response test data. MSC/NASTRAN's design optimization capability (SOL 200) is used to minimize the difference between the MSC/NASTRAN results and test data. In the procedure, the model parameters are automatically updated until the analytical results match the test data. The procedure is enabled in MSC/NASTRAN via the use of a user-written equation (DEQATN Bulk data entry) that defines the difference between test and analysis. An example is shown to illustrate the method.

PARAMETER ESTIMATION USING FREQUENCY RESPONSE TESTS (Acrobat 795 KB) #1894, 16 pgs. D. N. Herting -- FE Tools

ABSTRACT:

This approach bypasses many of the previous difficulties by using the following methods: 1) The error measures are defined directly from the solution vectors to avoid large complicated symbolic equation entries and manually transcribed data tables, 2) Frequency response solutions are used to avoid the difficult task of calculating eigenvector derivatives, and 3) Constraint equations are built into the solution to enforce test responses and produce faster convergence. A minor amount of automated preprocessing is the necessary extra effort to use the standard V68 system. Test results show the feasibility of the approach, and perhaps its practicality. Results will be shown for a classical example problem.

SIMULATION OF CRASH-TEST USING THE ACCELERATION AS A PARAMETER TO CHECK THEORETICAL AND EXPERIMENTAL RESULTS (Acrobat 418KB) #2094, 15 pgs. Luiz Carlos H. Ricardo -- Autolatina Brasil S.A. Oscar Bito Augsto -- Universidade São Paulo

ABSTRACT: A compact car was modeled using MSC/NASTRAN. The car model is composed by 6 beam elements and 2 rigid elements, also representing the engine and body masses, besides 2 other gap elements for mathematical reasons.

The hyphothesis was that a vehicle would make a crash-test at 14 m/s, with accelerometers placed in the tunnel. We have obtained, with this test, the curve acceleration versus time. These data were used for comparison with the MSC/NASTRAN model. Solution 129, transient non-linear response from version 67, was used.

Looking at the graphs and comparing the analysis, the MSC/NASTRAN versus experimental results are very close.

VALIDATION OF 3650 DWT SEMI CONTAINER SHIP FINITE ELEMENT MODEL BY FULL SCALE MEASUREMENTS (Acrobat 757KB) #1994, 13 pgs. Ricky L. Tawekal -- PT. PAL - INDONESIA (PERSERO) N.P. Miharjana -- PT. PAL - INDONESIA (PERSERO)

ABSTRACT: A vibration analyses of 3650 DWT Semi Container Ship using MSC/NASTRAN is presented in this paper. Measurements of the full scale ship are used to verify the numerical predictions by MSC/NASTRAN. Two finite element models are made to study the optimum size of the finite element model with adequate accuracy. The results show a good agreement between measurements and the corresponding numerical predictions where the differences of the lowest superstructure global natural frequency of the two models are less than 5%. The finite element models are then used to predict the effects of structural modification which was done to improve the vibration behaviour.

Testing and Applications

CROSS-ORTHOGONALITY CALCULATIONS FOR PRE-TEST PLANNING AND MODEL VERIFICATION (Acrobat 578KB) #7293, 19 pgs.
Ken Blakely -- The MacNeal-Schwendler Corporation
Ted Rose -- The MacNeal-Schwendler Corporation

ABSTRACT: Cross-orthogonality calculations can be used to compare the orthogonality of two different sets of mode shapes. Two types of calculations are described in this paper: MAC (Modal Assurance Criterion) and mass orthogonality. These calculations can be used for pre-test planning to guide proper selection of measurement instrumentation for a modal test, and can also be used to show the degree of correlation between modal test and MSC/NASTRAN mode shapes. This paper describes the implementation in Version 67.5 (via DMAP) and provides illustrative examples.

FINITE ELEMENT MODEL CORRELATION FOR STRUCTURES (Acrobat 578KB) #7393, 17 pgs.
Ricky L. Tawekal -- PT. PAL - Indonesia (Persero)
M. Agus Budiyanto -- PT. PAL - Indonesia (Persero)

ABSTRACT: Agreement between measured response of a structure and numerical predictions using an initial finite element model (IFEM) is in general poor. An algorithm is developed, which produces an updated finite element model (UFEM) that is fully correlated with respect to modal measurements. An incremental nonlinear methodology based on large admissible perturbations in cognate space is used to produce the UFEM by postprocessing the results of the initial finite element analysis (FEA) using MSC/NASTRAN. No additional FEA requiring trial and error adjustment is required. The UFEM corresponds to a real structure and may differ from the IFEM in response and correlation variables by 100-300 percent depending on correlation measures and structural size. Two numerical applications for a structure are used to assess the strength, and limitations of the large perturbation methodology.

PROCEDURE FOR FRF MODEL TUNING IN MSC/NASTRAN (Acrobat 629KB) #7193, 12 pgs.
D.L. Carlson -- Boeing Computer Services
S.A. Shapely -- Boeing Computer Services
T.F. Yantis -- Boeing Computer Services

ABSTRACT: Prediction of aircraft cabin noise relies on accurate frequency response analyses of engine, strut, nacelle, and wing components. Tuning the finite element model to accurately reflect the dynamic characteristics of the actual component hardware is an important part of this process. This paper discusses the development of a DMAP procedure for implementing Prof. David Ewins' approach to frequency response function (FRF) tuning in MSC/NASTRAN Version 67. Results are presented for simple test models which reveal some of the capabilities and limitations of the procedure.

TEST/ANALYSIS CORRELATION FOR MULTIPLE CONFIGURATIONS (Acrobat 773KB) #7493, 9 pgs. T. Ting -- University of Bridgeport

ABSTRACT: This paper extends the applicability of an existing sensitivity-based test/analysis correlation method, which permits the refinement of a finite element model by correlating with dynamic test results, to permit the simultaneous correlation with test results of multiple configurations. It also demonstrates a technique to overcome the limitation of most commercial FE programs in handling the integrated analysis task for a structure of multiple configurations in mass distributions, boundary conditions, and structural add-ons. Some promising features of this application has been revealed through a numerical example.

Thermal Analysis

DESIGN OF RAPID THERMAL PROCESSING SYSTEM BASED ON MSC/NASTRAN THERMAL ANALYSIS (Acrobat 732KB) #2195, 15 pgs.
Sergey Belikov--New Jersey Institute of Technology
Helen Martynov--New Jersey Institute of Technology
Michael Kaplinsky--New Jersey Institute of Technology

ABSTRACT: This paper describes a finite element model of rapid thermal processing (RTP) system for semiconductor manufacturing and its implementation with MSC/NASTRAN. The model is used for optimization of geometry and configuration of heating lamps in the RTP system. MSC/NASTRAN serves two main purposes: (1) calculation of parameters for design optimization algorithm using VIEW module; (2) performance evaluation of obtained configuration using heat transfer analysis. Condition of achievability of temperature uniformity is used as the goal of design in an interactive procedure with MSC/NASTRAN program in the kernel. Version 68 allows to improve the design procedure. Possible further refinements are discussed.

IMPLEMENTATION AND VERIFICATION OF A COUPLED FIRE MODEL AS A THERMAL BOUNDARY CONDITION WITHIN P3/THERMAL (Acrobat 64KB) 1996, 10 pgs. D. M. Hensinger--Sandia National Laboratories L. A. Gritzo--Sandia National Laboratories J. A. Koski--Sandia National Laboratories

ABSTRACT

MODELLING AND ANALYSIS OF AN ACCELEROMETER USING MSC/ARIES AND MSC/NASTRAN (Acrobat 1.17MB) #2295, 15 pgs.
Yeuan Jyh Ju--University of Bridgeport
Tienko Ting--University of Bridgeport

ABSTRACT:

STRESS ANALYSIS OF HYBRID PINS IN A WARPED PRINTED WIRING BOARD USING MSC/NASTRAN (Acrobat 480KB) #2095, 13 pgs. Kirit V. Patel--Sverdrup Technology, Inc.

ABSTRACT: During manufacturing, when the hybrids are wave soldered on a plated-through hole printed wiring board, the heat effects cause the polyimide board to warp. Since the hybrids are rigid, any attempt to straighten the edge of the board will introduce the residual stresses in the pins of the hybrid. This paper presents finite element modeling of such an out-of-plane imperfection of the board. The stress analysis is performed to estimate the residual stresses in the hybrid pins using MSC/NASTRAN. Also, a chassis level random frequency response analysis is performed to show the use of excursion delimiter in reducing the vibration-induced deflections in the board.

THERMAL CONDUCTION AND THERMAL CONVECTION AS A SINGLE THEORY SOLVED WITH FINITE ELEMENT METHOD (Acrobat 64KB)1996, 10 pgs. Mircea Bocioaga-- Romanian Aeronautical Enterprise ABSTRACT: This paper presents a theory in which thermal conduction and thermal convection is solved with a single equation. This equation is a generalised form of Fourier law. The paper presents a method, based on Ritz-Galerkin theory, for solving this equation. A main application for this equation could be the heat transfer study between a fluid flow and a solid body. The most important element is, that this theory is done without the convection theory and without the computation of a convection coefficient. The domain in which the equation is solved is a finite element. The solution is a linear equation system where the unknown quantities are the temperature in the finite element nodes.
THERMAL DESIGN OF POWER MOSFETS OPERATING IN PARALLEL (Acrobat 256KB) 1996, 10 pgs. V. Parameswaran--Rockwell International

ABSTRACT

USE OF FINITE ELEMENT MODELS FOR DETERMINING RADIATION GEOMETRIC VIEW FACTORS (Acrobat 64KB) 1996, 8 pgs. Patrick Edson--Eastman Kodak Company Victor Genberg--Eastman Kodak Company

ABSTRACT

USE OF FINITE ELEMENT MODEL AND TEMPERATURE MEASUREMENTS FOR REAL TIME CONTROL OF ACTIVE SURFACE AND POINTING OF A 50 M RADIO TELESCOPE (Acrobat 65K) #3598, 13 pgs.
Frank W. Kan and Rajesh S. Rao--Simpson Gumpertz & Heger Inc.

ABSTRACT: The Large Millimeter Telescope (LMT) is a 50 m diameter radio telescope with an actively controlled segmented surface to be used for astronomy at millimeter wave lengths. The specifications call for a surface accuracy of 70 micrometers RMS and a pointing accuracy of 0.7 arcseconds RMS. This paper evaluates a proposed approach for computing and correcting in real time the surface deformations of the primary reflector and the pointing errors of the telescope due to thermal deformations using a finite element model and temperature measurements throughout the telescope structure.

1993-1999 MSC Users' Conference Proceedings

Categories

Solutions

Services

Products

Academia

Resources

Communities

About Us

Support

Hide