MSC 1988 World Users' Conference Proceedings

The conference proceedings for the 1988 World Users' Conference are now available on-line in Adobe Acrobat PDF format. (The Adobe Acrobat Reader software is available for free download from Adobe's web site at www.adobe.com.) When printed, these PDF files will produce a better quality image than the one shown on your computer screen.

OVERVIEW OF MSC'S PLANS AND PROJECTS (Acrobat 538K) #0188, 6 pgs.
Joseph F. Gloudeman, President and CEO--The MacNeal-Schwendler Corporation, Los Angeles, California

ABSTRACT: The 1988 MSC World Users Conference is a noteworthy event, especially because it serves to help us officially celebrate the 25th Anniversary of The MacNeal-Schwendler Corporation. I would like to start by giving you a brief overview of our business environment, followed by the factors that influence our research, development and maintenance efforts. This leads to a discussion on recent development thrusts and identification of some of the major tasks ahead. Following this is a discussion of the role the clients play-both in helping us chart our future and in helping to minimize our risks.

STATUS OF MSC PRODUCTS #0288 (TEXT NOT AVAILABLE)
M.A. Gockel, VP, Technical Operations--The MacNeal-Schwendler Corporation, Los Angeles, California

ABSTRACT: The status of all products delivered since the last Users Conference and the content of those in development now are discussed. Some changes in approach towards integrating our products, based on the experiences of the last twenty-five years, are described.

AN OVERVIEW OF RECENT DEVELOPMENTS IN STRUCTURAL MECHANICS #0388
Tom Hughes--Stanford University, Stanford, California

Text Not Available.

STRUCTURAL SYNTHESIS USING MSC/NASTRAN (Acrobat 1.31MB) #0488, 14 pgs.
G.N. Vanderplaats, H. Miura--Engineering Design Optimization, Inc., Santa Barbara, California. G. Nagendra, D. Wallerstein--The MacNeal-Schwendler Corporation, Los Angeles, California

ABSTRACT: An automated structural syntheses capability has been developed as a set of internal modules of MSC/NASTRAN. The program takes advantage of utilities available in MSC/NASTRAN and is closely coupled with the sensitivity analysis capability to achieve overall numerical efficiency. The program architecture and data structure are designed open-ended to accommodate future extensions as new technologies become available. The concept of a design model is established as contrasted with the concept of analysis model, and the user interface to represent the design model is defined. In order to enhance flexibility in defining a variety of design models, a new capability to read mathematical equations as a form of bulk data is introduced. It is used to as well as to transform structural responses into special forms that the user may desire for the design model definition. Currently, the synthesis capability is limited to sizing problems, but the data and program structures are designed to readily accommodate shape design in the near-future.

ODYSSEY: A STRUCTURAL SIZING OPTIMIZATION PROGRAM USING NASTRAN (Acrobat 107K) #0588
A.K. Gupta, R.T. Wiggington, C.J. Wouden, and J.F. Yang--EDS, Warren, Michigan. M.E. Botkin, R.V. Lust--General Motors Research Laboratories, Warren, Michigan

ABSTRACT: The development of design sensitivity analysis in MSC/NASTRAN has allowed the implementation of efficient structural optimization programs which use MSC/NASTRAN as the analysis capability. The ODYSSEY (Optimum DYnamic and Static Structural Efficient SYstems) program will find a minimum mass structure subject to constraints on stress, displacements, and frequencies. ODYSSEY has been developed from the standpoint of providing the engineer with a tool to build a designmodel of the proposed structure. A design element library has been created which includes several common beam cross sections where the design variables are associated with physical section dimensions. Appropriate intermediate variables are internally established to create high quality approximations for the optimization steps. A multiple boundary condition, multiple load condition format has been developed using DMAP alters which allows any combination of static, inertia relief and eigenvalue analysis to be run simultaneously. NASTRAN case control input streams are automatically generated from a simplified design model input which is needed to link the analysis types with the constraint information. The RIM relational data base program is used to interface the various modules which make the optimization data easily available for post processing. Several example problems are used to illustrate the capabilities of the program.

STRUCTURAL OPTIMIZATION INCLUDING CENTRIFUGAL EFFECTS (Acrobat 740K) #0688, 12 pgs.
Howard D. Gans--Air Force Institute of Technology, Wright-Patterson AFB, Ohio. William J. Anderson--University of Michigan, Ann Arbor, Michigan.

ABSTRACT: This paper investigates the effects of centrifugal forces on the frequencies of a rotating system and then provides an optimal redesign process. The rotational effects have a profound influence on the eigenfrequencies and are important in optimal structural redesign where the frequencies must be adjusted. The optimal redesign is done by deriving nonlinear inverse perturbation equations for the problem. Structural changes typically meet the frequency goals to within three percent.

THE OPTIMAL DESIGN OF STRUCTURAL SYSTEMS BY THE SUPERELEMENT METHOD (Acrobat 469K) #0788, 8 pgs.
J-Shan Huang--Aeronautical Research Laboratory, Taichung, Taiwan, ROC

ABSTRACT: Recently, the analytical methods of the optimal structural design is to utilize the sensitivity technique. This approach is then a programming problem. In order to arrive at an optimal size for a structural element by solving the programming problem, the sensitivity analysis must be repeated by computation of the structural matrices. The process may consume large amount of computer time. For practical applications, how to arrive it the most efficient mathematical model for this purpose is of major preference This paper present, the superelement method and the sensitivity analysis technique for optimal structural design for this regard, personal computers using prove to be an economic means to apply there methods.

USING MSC/NASTRAN IN IMPACT MANAGEMENT APPLICATIONS (Acrobat 469K) #0888, 10 pgs.
David A. Bobinger--Delco Products Division, Dayton, Ohio

ABSTRACT: Management of the energy encountered during a collision in automotive applications has been of interest for many years in the industry, and since 1973, Delco Products, a division of General Motors, has been a leader in supplying energy absorbing devices (EADs) to the automotive community. The EAD designed by Delco Products consists of a gas pressurized unit that is located behind the bumper and assists in the management of the loads generated during an impact. This paper describes the analysis techniques used by Delco Products to design mass efficient and cost effective impact management components. Using an Intergraph CAD/CAM system in conjunction with MSC/NASTRAN and PDA PATRAN, EADs are simulated to reduce weight and increase efficiency. A vital part of this procedure includes correlation with data acquired from actual vehicle barrier and pendulum testing. The analysis methods employed in these design procedures are linear, static finite element techniques to study structures undergoing complex, impact loading. Through the use of the CAD/CAM system and the simplified analysis approach, several design modifications to various components can be evaluated quickly and effectively, resulting in shorter design development time and improved usage of test facilities.

TIME-DEPENDENT RESTRAINED BOUNDARY CONDITION SIMULATION (Acrobat 588K) #0988, 10 pgs.
Shan Lin -- FMC Corporation, Minneapolis, Minnesota

The study of transient forces and displacements a common topic in the analysis of structural and machinery dynamics. Widely used analysis tools are the MSC/NASTRAN Version 64 Solutions 27, 31, 72, and 99. One limitation of this program is that time-dependent restrained mechanisms can not be directly modelled. In this paper, a method will be described to address this problem. The latch in a gun barrel recoil system represents a time-dependent restrained boundary condition. The time domain was divided into two parts. In the first, latch reaction forces were computed assuming that the latch was restrained. The output for this case was then used as input for the solution of the second portion of the transient analysis. Here, the latch dynamics were computed assuming that the reaction forces are reset to zero at the time of latch release. The computed restraining forces and the results show that the procedure is a convenient method for analyzing time-dependent restrained boundary conditions.

THE ANALYSIS OF STRUCTURAL DYNAMIC EFFECTS ON IMAGE MOTION IN LASER PRINTERS USING MSC/NASTRAN (Acrobat 952K) #1088, 8 pgs.
Bill Nowak--Xerox Corporation, Webster, New York

ABSTRACT: This paper describes the application of MSC/NASTRAN to calculate and experimentally correlate the dynamic response of a xerographic laser printer write head known as a "raster output scanner" (ROS). Steady and transient dynamic loading conditions are applied to a structural model of the ROS component support casting which has multi-point constraint equations accounting for the optomechanical interaction of 14 laser spot conditioning lenses and mirrors with the mounting structure. The output of the the MPC relationships describe the dynamic response of the laser spot at the photoconductor surface. The response amplitude is then compared to a motion specification to determine if perceptible defects in xerographic prints will occur.

DYNAMIC ANALYSIS OF OPTICAL BEAM POINTING (Acrobat 125K) #1188
P.J. Woytowitz--Failure Analysis Associates, Palo Alto, California. K.C. Jiang, K.P. Bhat--Ford Aerospace and Communications Corporations, Palo Alto, California

ABSTRACT: The effect of mechanically induced structural vibrations on the pointing accuracy of an imaging instrument mounted on a large spacecraft is studied. The structural analysis of this phenomenon is performed using MSC/NASTRAN.

Two types of analyses are described. The first analysis consists of a fixed base model of the instrument. The instrument is reduced to a modal model using MSC's Generalized Dynamic Reduction (GDR). The generalized mass and stiffness matrices generated by (GDR) are used as dynamic representations of the instrument. Modes up to 150 Hz are retained in the instrument. Both modal coordinates and physical coordinates are contained in the matrices. The modal matrices are obtained from the instrument model assuming the control systems are inactive. Excitation is then applied in the form of a fixed base acceleration using peak accelerations from a separate analysis of the spacecraft. The optical beam path is described utilizing an optical sensitivity matrix generated by an optics program. The beam pointing measures are written as functions of key structural displacements and incorporated using multi-point constraint equations. The control systems which control the beam pointing are approximated as second order systems with the coefficients calculated to simulate the electronic control circuits, sensors and actuators. These are incorporated in MSC/NASTRAN using the Dynamic Transfer Function and Direct Matrix Input capabilities. The beam pointing response with the control system active is then analyzed using a sine sweep input and MSC/NASTRAN modal frequency response capability.

The second analysis consists of a coupled instrument/spacecraft model. The modal matrices described above are introduced into the spacecraft model using the direct matrix input capabilities. The control systems are re-introduced using the same technique that was applied to the fixed base model. The loading condition considered is that due to reaction/momentum wheel imbalance. The loads are applied to the coupled spacecraft/instrument model and the resulting beam jitter is obtained.

The paper outlines the analysis techniques and implementations described above. Comparisons between the uncoupled approach (first analysis) versus the coupled approach (second analysis) are made. Finally the effects of using fixed base instrument modes versus free-free instrument modes are described and discussed.

COMPOSITE ANALYSIS USING SDRC SUPERTAB AND MSC/NASTRAN (Acrobat 64K) #1288
Louis E. Lux--SDRC/CAE International, Inc., Milford, Ohio

ABSTRACT: With requirements of reducing mass in many industrial applications, composites have gained a great amount of attention in recent years. With respect to milling machines, requirements of high traverse speeds and low inertia have led designers to look at laminate materials to increase rigidity and minimize mass during machining operations.

This paper describes a new interactive approach in composite analysis modeling using SDRC Supertab and interface with MSC/NASTRAN related to a milling machine beam and other industrial examples.

All phases of modeling, analysis, and post processing will be considered graphically to digest the vast amount of information involved in laminate analysis. Some of these phases include methods for creation of ply properties, definition of laminate, creation of finite element mode, failure envelope representation, and post processing stresses, strains, and failure indexes.

INTERACTIVE CROSS-SECTION DESIGN USING PATRAN AND MSC/NASTRAN (Acrobat 726K) #1388, 11 pgs.
Keith J. Meyer--PDA Engineering, Costa Mesa, California

ABSTRACT: The cross-section properties required for detailed beam analysis, including torsion and warping constants, shear stiffness factors, and optimal stress recovery points, can be difficult to calculate for even the simplest shapes. Complicated multi-cell, mixed openclosed sections are often used by the automotive and aerospace industries and the calculation difficulties overwhelm manual techniques. P/SECTION is an interactive and graphical program in the PATRAN system that accepts any shape defined by the parametric lines in PATRAN, automatically diagnoses the topological structure (cell boundaries, sectorial coordinates, etc.) and allows interactive review and remedial action (overlap identification, placement of spot welds, etc.) All cross-sectional properties required for beam analysis are then calculated and stored in an MSC/NASTRAN PBAR or PBEAM format, readily available for use in an MSC/NASTRAN structural analysis. The interactive, graphical abilities of P/SECTION enhance the advanced analysis and design features of MSC/NASTRAN for frame stiffened structures.

DERIVATION OF AN EQUIVALENT BEAM MODEL FROM A STRUCTURAL FINITE ELEMENT MODEL (Acrobat 469K) #1488, 10 pgs.
Ashok K. Singh, Christian W. Nichols--Northrop Aircraft, Hwthorne, California

ABSTRACT: An equivalent beam model is derived from an MSC/NASTRAN finite element model of a horizontal stabilizer structure. An automated interactive graphics program has also been developed to obtain the elastic axis and beam stiffness of the surface.

PROCEDURE FOR PROCESSING AND DISPLAYING ENTIRE PHYSICAL MODES BASED ON RESULTS GENERATED THROUGH COMPONENT MODE SYNTHESIS #1588
J.J. Brown, J.M. Lee, G.R. Parker, and K. Zuhuruddin--Hughes Aircraft Company, Los Angeles, California

No Text Available.

THE APPLICATION OF REANALYSIS TECHNIQUES TO LARGE FINITE ELEMENT MODELS THROUGH NASTRAN DMAP (Acrobat 920K) #1688, 17 pgs.
C.M. Smith--McDonnell Aircraft Company, McDonnell Douglas Corporation, St. Louis, MO

ABSTRACT: In the past few years large finite element modeling of dynamics problems has become more and more common. This is not surprising since larger, more powerful computers are being brought into service and analysis complexity is usually a half step ahead of capability. If the dynamacist wants to make the most of the existing computing facilities he must find ways to simplify or reduce the size of the problems being worked. In the aircraft industry the normal approach is to reduce the structure of interest to an equivalent lumped mass and stiffness representation using beams and concentrated mass. This was and is still done for most aircraft lifting surfaces. When there is no convenient way to reduce a structure, the reduction can sometimes be accomplished in the solution phase. NASTRAN has two commonly used normal mode analysis reduction techniques, Guyan and Generalized Dynamic Reduction. Both approaches select a reduced set of coordinates that represent the total dynamic behavior of the structure analyzed. The solution is more efficient but it is only an approximation. The accuracy of the approximation is generally very good and a useable solution results. A different approach to dynamic reduction has been explored recently with excellent results. It is called the assumed mode reanalysis technique.

SPACE STATION DYNAMIC ANALYSIS WITH ACTIVE CONTROL SYSTEMS USING MSC/NASTRAN (Acrobat 488K) #1788, 9 pgs.
S. Ghofranian, O.D. Diammagio--Rockwell International Corporation, Downey, California

ABSTRACT: Since the early stages of the space station program one of the concerns has always been the interaction between structural flexibility and the various on board control systems. Each configuration change initiated a structure/control interaction study to determine whether control requirements can be satisfied.

EXAMPLE PROBLEMS ILLUSTRATING THE EFFECT OF MULTIPLE CROSS CORRELATED EXCITATIONS ON THE RESPONSE OF LINEAR SYSTEMS TO GAUSSIAN RANDOM EXCITATIONS (Acrobat 463K) #1888, 8 pgs.
F.W. Palmieri--Palmieri Consulting Co., Inc., Anaheim, California

ABSTRACT: Several simple example problems have been provided demonstrating the application of the multiple source capability of MSC/NASTRAN rigid format solution 30. In particular, the effect of various amounts of cross correlation of the input sources is investigated. It is shown through the examples that the peak value of output dis-placements, stresses, etc. may occur for values of cross correlation other than that resulting from fully correlated sources.

A METHOD FOR PREDICTING THE OUTPUT CROSS POWER SPECTRAL DENSITY BETWEEN SELECTED VARIABLES IN RESPONSE TO ARBITRARY RANDOM EXCITATIONS (Acrobat 879K) #1988, 16 pgs.
F.W. Palmieri--Palmieri Consulting Co., Inc., Anaheim, California

ABSTRACT: A derivation of the response of lumped parameter, linear systems to random vibration excitations has been provided in order to extend the method to enable the prediction of the output cross power spectral density existing between various degrees of freedom.

RESONANT RESPONSE OF HELICOPTER GEARS USING 3-D FINITE ELEMENT ANALYSIS (Acrobat 123K) #2088
Raymond J. Drago and Ravi N. Margasahayam--Boeing Helicopter Company, Philadelphia, Pennsylvania

Dynamic analysis of a lightweight, heavily loaded, high speed helicopter gear is presented for identification and correction of resonance behavior. Using normal modes solution of MSC/NASTRAN, natural frequencies and related mode shapes were defined. Identification of damaging resonances occurring within the transmission operating range was accomplished with the aid of Campbell diagram technique. A comparison of FEM results and those from actual tests on an existing part indicated good correlation. Often neglected in the initial design process, evaluation of gear resonant response must be fully integrated in the design cycle.

USING MSC/NASTRAN TO OBTAIN MODAL PARAMETERS (Acrobat 707K) #2188, 11 pgs.
Cuann-yeu Chang and Yuan-bing Chang--Aeronautical Research Laboratory, Taichung, Taiwan, ROC

ABSTRACT: Natural frequencies and mode shapes are fundamental parameters for almost all dynamic analyses. It is not difficult to obtain a set of accurate results if users are familiar with finite element characteristics and NASTRAN usages. Herein the whole pictures are dealt with and the discussions on each procedure are made for performing the modal analysis of air vehicles. First of all, guidelines to determine how fine the mesh is for different modeling objectives are studied. At the same time, the capability of using suitable finite elements to reflect real characteristics of the global and local system is essential and worth to note. On the other hand, for a large structure, not all the d.o.f.'s can be put into eigensolver, only a small set can be left, the degree of accuracy remained have to be considered prudently. Thus, the general rule of dynamic reductions provided by NASTRAN is discussed. Meanwhile, several error messages usually occurred are noticed and the keys to avoid them are hereby mentioned, too. Finally the comparison between analytical results and testing results is also conducted by NASTRAN DMAP and some externally written FORTRAN programs.

LAPCAD3: A MODELING PROGRAM FOR MSC/PAL (Acrobat 1.04MB) #2288, 17 pgs.
Gert M. Lundgren--LAPCAD Engineering, Chula Vista, California

ABSTRACT: LAPCAD3 is a modeling program for interaction with MSC/pal on the Macintosh.

Objects are created and viewed in 3-D solid and shaded perspective. The finite element modeling features include the creation of nodes in the 3-D space. The nodes are connected into bars and triangular and quadrilateral plates.

Models are stretched, copied, mirrored, moved, rotated or erased. Element properties, materials, boundary conditions and external loads are implemented under mouse control. Element shrink mode and hidden line removal is implemented. A standard Macintosh-like interface is utilized.

Stiffness and loads data is saved and printed in either MSC/pal or MSC/NASTRAN format.

MECHANICAL/STRUCTURAL DESIGN WITH MACINTOSH (Acrobat 193K) #2388, 3 pgs.
Thomas J. Lazear--Versacad Corporation, Huntington Beach, California

ABSTRACT: The Macintosh computer has long been a favorite of engineers and designers because of it's easy interface and because of the standardization between applications. The Macintosh II now provides color and power for the Macintosh to move into greater applications and to capture a larger share of the market.

OVERVIEW OF CADAM-MSC INTERFACES, CADAM FEM PRE-PROCESSING, AND AUTOMATIC MESH GENERATION (Acrobat 379K) #2488, 5 pgs.
Henry J. Schultz--CADAM Inc., Burbank, California

ABSTRACT: CADAM, INC has been a CAD/CAM leader for more than 20 years with thousands of production users the world. In the past, the emphasis has been on manufacturing applications. With the introduction of CADAM's mew CIMCORE strategy, the integration of CAE applications with traditional CAD/CAM products has assumed central importance. Current FEM capabilities as they exist within CADAM's 3D MESH product will be briefly reviewed after which there follows a discussion of automatic mesh generation using CADAM's Interactive Solid Design (ISD) solid modeller.

COMPUTER-AIDED DECK DESIGN USING MSC/pal AND AutoCAD (Acrobat 610K) #2588, 7 pgs.
Charles Kung--Montgomery College, Germantown, Maryland

ABSTRACT: A carefully designed deck can substantially increase the living space of a house and make the outdoors more joyful. This paper presents an integrated computer-based technique to automate the design of a wood deck. The design parameters including geometry, material, boundary conditions, and loads are entered to the computer by the user through the control of an AutoLisp program. A database of design codes is stored in the computer. Autolisp checks the design parameters and the database and generates an AutoCAD drawing of the deck interactively. From the drawing, MSC/AutoFEM generates a finite element model file. The model file is then fed to MSC/pal 2 for analysis. The result is fed back to the AutoLisp program for revaluation and decision making. Should the design be unsatisfactory, a modified design starts automatically. Several iterations may be necessary. Finally, the finished deck design is presented in the form of a drawing and bill of material.

TOMBEAU DE ROBERT SCHWENDLER #2688
Thomas G. Butler--Butler Analyses, Lutherville, Maryland

Text Not Available.

SIMULATION OF ROOM TEMPERATURE CONTROL SYSTEM (RTCS) WITH MSC/NASTRAN
(Acrobat 913K) #2788, 15 pgs.
Ernest B. Paxson, Jr.--Paxson Engineering Services, Albuquerque, New Mexico

ABSTRACT: The problem to which the title of this paper refers was spawned in the process of learning how to implement MSC/NASTRAN in a structure-optics-controls application. In choosing a vehicle to accomplish the first step of this learning process, one might reason that a Room Temperature Control System (RTCS) would furnish a non-trivial mathematical model but one not so complex as to prevent obtaining a closed form solution with which to compare the MSC/NASTRAN analysis results.

ANALYSIS OF WATER DISTRIBUTION NETWORKS USING MSC/NASTRAN (Acrobat 433K) #2888, 8 pgs.
Arturo O. Cifuentes--The MacNeal-Schwendler Corporation, Los Angeles, California

ABSTRACT: A problem that arises very frequently in applied hydraulics is the study of steady imcompressible flows in a network of pipes. This paper introduces a structural analogy that allows the problem to be treated with MSC/NASTRAN using the nonlinear statics capability.

A TRANSIENT RESPONSE OF AN ELECTROMECHANICAL DEVICE USING TIME VARING MAGNETIC FORCES AND A REVIEW OF THE DIFFERENCES IN APPROACH REQUIRED IN MAGNETIC FINITE ELEMENT ANALYSIS (Acrobat 1.66MB) #2988, 22 pgs.
G.E. Barron--CAD COMP Inc., Milwaukee, Wisconsin

ABSTRACT: Mechanical motion is produced by magnetic fields in devices such as solenoids and electric motors. Prediction of the motion involves first calculating the magnetic forces and then calculating the resulting mechanical response. In this paper the method of calculating both the magnetic forces and the resulting displacements is the finite element analysis method (FEA).

USE OF INERTIA RELIEF WITH REFLECTIVE SYMMETRY (Acrobat 529K) #3088, 7 pgs.
William J. Anderson, Jianhong Zhang, Thomas Kubr--The University of Michigan, Ann Arbor, Michigan

ABSTRACT: Many moving bodies for which inertia relief is desired also have a reflective plane. It is not obvious how to use MSC/NASTRAN to include both effects. There are conflicting procedural requirements for using the SUPORT condition and for boundary conditions on the reflective plane when general loading is present. A procedure has been worked out to obtain the proper support at the plane of symmetry so that a single computer run suffices. The approach is approximate, but the error can be driven below 1% by properly tuning the constraints in terms of location, mass, and stiffness of artificially introduced ROD elements.

STATIC ANALYSIS USING INERTIA RELIEF TECHNIQUE TO EVALUATE A HOOD STRUCTURE FOR SLAM/DROP LOADS (Acrobat 1.21MB) #3188, 28 pgs.
H.N. Agrawal, S.G. Kelkar, N.J. Pritula, R.A. Shipman--Ford Motor Company, Dearborn, Michigan

ABSTRACT: To develop a static analysis technique to analyze a hood structure under slam/drop type loading, using finite element methodology and to apply the technique to a typical hood structure.

A NASTRAN PRIMER FOR THE ANALYSIS OF ROTATING FLEXIBLE BLADES (Acrobat 697K) #3288, 10 pgs.
Charles Lawrence, Robert A. Aiello, Michael A. Ernst--NASA Lewis Research Center, Cleveland, Ohio. Oliver G. McGee--Ohio State University, Columbus, Ohio

ABSTRACT: This primer provides documentation for using MSC NATRAN in analyzing rotating flexible blades. The analysis of these blades includes geometrically nonlinear (large displacement) analysis under centrifugal loading, and frequency and mode shape (normal modes) determination. The geometrically nonlinear analysis using NASTRAN Solution sequence 64 is discussed along with the determination of frequencies and mode shapes using Solution Sequence 63. A sample problem with the complete NASTRAN input data is included. Items unique to rotating blade analyses, such as setting angle and centrifugal softening effects are emphasized.

STRESS ANALYSIS OF CN-235 FLAPTRACK FOR FATIQUE LIFE DETERMINATION (Acrobat 433K) #3388, 8 pgs.
S. Kamil, A. Pramono, T. Santoso, A. Ismadi--IPT. Nusantara Aircraft Industries, Bandung, Indonesia

ABSTRACT: Flaptrack is a vital component connected to the wing box structure to allow the flap extension and retraction, in order to raise the lift by changing the curvature of airfoil section. The Aviation Regulation requires strength analysis proven by testing.

This paper describes stress analysis of the flaptrack using finite element method in order to support fatique life determination. The analysis is compared with experimental result.

THERMAL DISTORTION ANALYSIS FOR GOES SATELLITE USING MSC/NASTRAN (Acrobat 90K) #3488
James L. Bockholt, Kun-Chen Jiang--ford Aerospace Corporation, Palo Alto, California

ABSTRACT: Distortions of the on-orbit Geostationary Orbiting Environmental Satellite (GOES) due to diurnal and seasonal temperature changes effect the pointing accuracy of the on-board optical instruments (imager, sounder, and earth sensor). If the thermal distortion profiles are smooth and repeatable, the pointing errors can be easily accommodated through the image motion compensation system. This paper describes the thermal distortion analyses performed for the GOES satellite mainbody using MSC/NASTRAN. These analyses included transferring temperature data from the TAP thermal model to the MSC/NASTRAN structural model, performing thermal distortion sensitivity studies of the satellite panel-to-panel connections, and calculating diurnal and seasonal distortion profiles of the imager/sounder interface relative to the earth sensor. A FORTRAN program was developed to transfer the temperatures from thermal model to the structural model. MSC/NASTRAN Solution 24 Heat Transfer feature was used to interpolate temperatures among the structural grid points. Results of the connection sensitivity study indicated that the assumption of 'pinned' panel-to-panel connection is more conservation than the 'fixed' panel-to-panel connection. Thermal distortion profiles generated for Summer Solstice, Winter Solstice and Equinox were smooth except for the eclipse period of Equinox. These results indicated that the pointing errors due to thermal distortion of satellite mainbody can be easily accommodated through the image motion compensation system.

THERMAL DISTORTION ANALYSIS OF A WF/PC QEH ENTRANCE MIRROR (Acrobat 840K) #3588, 9 pgs.
Paul M. Rapacz-Jet Propulsion Laboratory, Pasadena, California

ABSTRACT: This paper describes the use of MSC/NASTRAN in determining the temperature distribution and subsequent surface distortion of the Wide Field/Planetary Camera (WF/PC) Quantum Efficiency Hysteresis (QEH) light pipe entrance mirror. Temperature variations due to electrical base heaters, solar radiation and radiative heat loss were calculated for various on-orbit thermal loading conditions. Mirror deformations were then found by imposing these temperatures as temperature loads in a structural analysis. Use of an RBE3 generated leastsquares best fit reference plane to measure surface distortion and pointing error along with experiences in using radioactive heat transfer are also discussed.

EFFICIENT AND ACCURATE ENCLOSURE RADIATION CONCEPTS FOR FINITE ELEMENT CODES (Acrobat 551K) #3688, 12 pgs.
Mike Chainyk--The MacNeal-Schwendler Corporation, Los Angeles, California

ABSTRACT: Three dimensional heat transfer with enclosure radiation requires the calculation of surface to surface geometric view factors. View factors for diffuse emitters and reflectors are traditionally developed by evaluating area or line integral equations for every pair of surfaces which see each other. An N surface enclosure can have N2 unique view factors. Employing reciprocity and summation rules as many as N(N-1)/2 view factors may require calculation. If the surfaces are convex or flat, N of these view factors from a surface to itself are eliminated and the number of view factors to be calculated reduces to N(N-3)/2.

SOLUTION OF GENERAL FIELD PROBLEMS WITH MSC/cal (Acrobat 580K) #3788, 13 pgs.
Daniel Chu--The MacNeal-Schwendler Corporation, Los Angeles, California

ABSTRACT: The MSC/cal Version 2.0 heat transfer software is a versatile tool not limited to the area of heat transfer, but capable of solving various engineering field problems such as potential flow in fluid mechanics, electrostatic field analysis, see page (Darcy's Law) analysis, and mass transfer. This is due to the fact that all the physical phenomenon in the above disciplines is dictated by Poisson's equation:

ACCURATE AND EFFICIENT MODE ACCELERATION DATA RECOVERY FOR SUPERELEMENT MODES (Text Not Available) #3888
Christopher C. Flanigan--Structural Dynamics Research Corporation, San Diego, California

ABSTRACT: Procedures are described for accurate and efficient mode acceleration data recovery of transient responses for superelement models. The procedures are more accurate and MSC/NASTRAN's standard mode acceleration data recovery. The steady state portion of the transient response is calculated using the complete stiffness matrix. This is more accurate than using the residual structure stiffness matrix formed from static and dynamic condensation of the upstream superelements. The dynamic portion of the response is calculated using the acceleration of the elastic normal modes. Special provisions are provided for solving the steady portion of the response for structures with rigid body modes. The procedures are very efficient for large models with relatively few load vectors and with large numbers of integration steps. The procedures are demonstrated using an example problem.

APPLICATION OF MSC/NASTRAN SUPERELEMENT DYNAMIC REDUCTION TECHNIQUES FOR THE VERTICAL LAUNCHING SYSTEM (Acrobat 816K) #3988, 11 pgs.
Tejbir Arora, Lily Birmingham--Martin Marietta Aero and Naval Systems, Baltimore, Maryland

ABSTRACT: The MK 41 Vertical Launching System (VLS) is a large complex structure and it's finite element model represents approximately 80,000 degrees of freedom (DOF's). The MSC/NASTRAN superelement method was used to model the VLS structure. In order to reduce the cost for the residual run, generalized dynamic reduction (GDR), Guyan reduction and component mode synthesis techniques were implemented. The VLS contains 8 modules and a standard module has 8 cells. As an aid to the analysis set (A-set) selection for the over all VLS model, a single cell model was studied. The results of this small model study are presented here. A comparison for the frequencies calculated using Guyan reduction with various A-sets versus using GDR is included. The optimized A-set for Guyan Reduction was identified based on the results. Subsequently, similar selection was used for every cell in the VLS model. This study provided the cost saving and the accuracy for optimizing the A-set selection for the VLS analysis.

SUPERELEMENT DATA RECOVERY VIA THE MODAL ACCELERATION METHOD (Acrobat 85K) #4088
Guy Buchanan--General Dynamics, San Diego, California

ABSTRACT: A method is presented for obtaining upstream superelement internal displacements and element stresses and forces using the modal acceleration method. The solution is in the form of load transformation matrices, however extrapolation to a solution sequence alter should be possible. Though NASTRAN solution 63 can employ the modal acceleration method to obtain displacements within the residual, upstream data recover utilizes a simple expansion of each superelement by solving the internal displacements and hence element forces and stresses. The new method is analytically developed for a generic superelement by solving the internal partition of the superelement equation of motion for the internal displacements. The augmented set of superelement internal displacements obtained are a function of the superelement modal accelerations, boundary accelerations, and boundary displacements. These displacements are then used to deform the superelement elemental stiffness matrix for element loads. The NASTRAN implementation of this procedure is described as a series of stand alone DMAP programs, DMAP alters and stand alone Fortran programs. A test case is used to compare the enclosed method, standard NASTRAN data recovery, and an exact finite element solution. Also included is a brief description of an exemplary analysis of a space vehicle upper stage of substantial complexity on a CRAY computer, including some of the problems incurred and their solutions.

USING SUPERELEMENTS TO IDENTIFY THE DYNAMIC PROPERTIES OF A STRUCTURE (Acrobat 1.16MB) #4188, 18 pgs.
Ted L. Rose--The MacNeal-Schwendler Corporation, Los Angeles, California

ABSTRACT: The following paper contains an MSC/NASTRAN DMAP for Solution 63, which, with the proper partitioning into Superelements, provides an excellent method of identifying the normal modes of a model. In addition, by using parameters, the DMAP will perform a series of static checks on each superelement.