MSC 1986 World Users' Conference Proceedings

The conference proceedings for the 1986 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.

A BRIEF OVERVIEW OF THE MACNEAL-SCHWENDLER CORPORATION (Acrobat 408K) #1A86, 6 pgs.
Joseph F. Gloudeman--President and Chief Executive Officer, The MacNeal-Schwendler Corporation

ABSTRACT: The MacNeal-Schwendler Corporation has underfone some significant changes in recent years. Because many of our clients do not have the opportunity to keep up with these changes, I would like to give you an update on our organization structure, and product thrusts. I intend to touch on these only very briefly because you will be getting more detailed information from Mike Gockel shortly-and from others over the next two days.

STATUS OF MSC PRODUCTS, 1986 (Acrobat 1.73MB) #1B86, 32 pgs.
M.A. Gockel, The MacNeal-Schwendler Corporation

A PowerPoint presentation.

A MODERN FAMILY OF CRACK TIP ELEMENTS FOR MSC/NASTRAN (Acrobat 1.20MB) #0286, 25 pgs.
Jatin C. Parehk, Rocky R. Arnold, Peter J. Woytowitz--Anamet Laboratories, Inc., San Carlos, California

ABSTRACT: Two new Crack Tip Elements (CRAC2D and CRAC3D) have been developed and incorporated into MSC/NASTRAN. The elements are considered linear, isotropic, and homogeneous. Mode I, II and III stress intensity factors are automatically calculated. Comparisons to theoretical solutions for several geometries are presented and demonstrate the accuracy of the developed elements Extensions of the elements are discussed.

COMPARISON OF BOUNDARY ELEMENT AND FINITE ELEMENT METHODS FOR LINEAR STRESS ANALYSIS-TECHNICAL PROGRAM RESULTS (Acrobat 902K) #0386, 20 pgs.
Arturo Wanderlingh--Specialist Applied Numerial Analysis, Applied Mechanics Group, Hamilton Standard--Division of United Technologies Corporation, Windsor Locks, CT

ABSTRACT: Over the years, engineering organizations have become increasingly dedicated to improving productivity through the use of high-speed computers, computer-aided design and manufacturing (CAD/CAM) techniques and computer-aided analysis methods such as the Finite Element Method. Despite the analytical method's substantial impact on spite the analytical method's substantial impact on productivity, three limiting factors persist: 1) the difficulty in identifying connectivity errors, particularly in 3D models, 2) the need to discretize the entire volume of a structure, and 3) the density of the mesh needed to obtain accurate surface stresses. A numerical technique which has a potential for eliminating these shortcomings is the Boundary Element Method. The purpose of this paper is to discuss the results of a technical program conducted at Hamilton Standard, comparing the Boundary Element and Finite Element Methods for two- and three-dimensional, linear structural analyses.

EVALUATION OF THE P-VERSION OF THE FINITE ELEMENT METHOD (Acrobat 1.89MB) #0486, 38 pgs.
Kamran Izadpanah--The MacNeal Schwendler Corporation

ABSTRACT: The field of finite element analysis has been the subject of intense development for many years [1, 2] and this tool in conjunction with the powerful computers available today, make finite element analysis an important part of the engineering analysis field. The methodology that most of the current commercially available codes, such as MSC/NASTRAN, are based upon is the so called h-version methodology which is based upon discretization of an engineering problem into many small finite elements (h) and assuming a linear or at most quadratic distribution of the unknown parameters in those small finite elements. The success of this methodology has been so great that little attention was given to the p-version of the finite elements were no longer restricted to linear or quadractic, but to an arbitrary higher order p. This methodology, which was virtually abandoned in the early stages of the development, has made some very interesting advances in the last few years [3, 4, 5] and is the topic of this paper.

INTEGRATED DYNAMIC TEST/ANALYSIS PROCESSOR OVERVIEW (Acrobat 1.49MB) #0586, 24 pgs.
Robert N. Coppolino--The MacNeal-Schwendler Corporation

ABSTRACT: A new system which provides integrated dynamic testing and mathematical model analysis capability is described. The integrated system addresses four key tasks, namely, (1) pretest planning and analysis, (2) test data acquisition, (3) data reduction and analysis, and (4) test/analysis correlation and mathematical model updates. Several key software programs are employed to accomplish this task. The are MSC/NASTRAN, MSC/STI-VAMP and MSC/GRASP, along with appropriate interface utilities. A simple tower structure is used to illustrate operation of the integrated test analysis processor.

MSC/NASTRAN DYNAMIC ANALYSIS: MODAL OR DIRECT? (Acrobat 2.14MB) #0686, 42 pgs.
Vern D. Overbye--A.O. Smith Data Systems, Inc.

ABSTRACT: MSC/NASTRAN offers dynamic analysis capability using direct or modal formulations with or without superelements. This paper compares computer resources and results accuracy using direct and modal analysis of a linear, nonsuperelement vehicle-type structure. A novel approach to response spectra capability is used to determine forcing function frequency content. A real eigenvalue primer is also included in an appendix.

SHOCK WAVE PROPAGATION AND NASTRAN LINEAR ALGORITHMS (Acrobat 1.65MB) #0786, 22 pgs.
Dr. M.M. Moharir, Senior Engineering Specialist--General Dynamics Space Systems Division, San Diego, California

ABSTRACT: A study is conducted to investigate usage of NASTRAN as a viable tool to analyze shock wave propagation through solids. Fundamental variables such as velocity of sound, maximum length of unreflected travel, duration of pulse, finite-element dimensions, analysis time step, fundamental period of the structure, etc. are identified and their mutual relationship established for the proper solution in NASTRAN environment. Modal and direct transient algorithms with superelements are covered for the impulse and the enforced motion shock waves.

CONSPEC-A DMAP SYSTEM FOR CONVENTIONAL RESPONSE-SPECTRUM ANALYSIS IN MSC/NASTRAN (Acrobat 3.54MB) #0886, 53 pgs.
A. Parthasarathy--Systems and Services Division, Control Data Canada, Limited, Mississauga, Ontario, Canada

ABSTRACT: This paper describes the features of a DMAP system called CONSPEC that implements a conventional response-spectrum analysis in MSC/NASTRAN. The term "conventional" refers herein to an approach based on the relative-motion concept and on post-processing of a standard SOL-3 eigensolution. CONSPEC, unlike SOL-63, obviates the need for fictitious modelling details. It accommodates a wide range of damping representations. It can output individual-mode contributions to total response and can sort element forces/stresses. An intermediate, but optionally stand-alone, step in CONSPEC evaluates and outputs useful modal measures such as participation factors, effective masses, damping factors and mode-trancation-effectiveness matrix. In effect, CONSPEC enables the average NASTRAN-user to realize most of his practical requirements in response-spectrum analysis without any artificial model augmentation and special DMAP procedures.

MSC/NASTRAN MODAL CHECKOUT (Acrobat 2.89MB) #0986, 56 pgs.
Frank Tillman, Robert Galletly--Jet Propulsion Laboratory, Pasadena, California, John Zins--Consultant

ABSTRACT: This paper describes a procedure for systematically checking and verifying a NASTRAN finite element model. Various methods and levels of model checkout are used at the Jet Propulsion Laboratory (JPL) and all of them are combined in this paper to ensure that the models are consistent, mathematically well conditioned, and documented. Some of the techniques presented are:

  • 1G XYZ Gravity Loads (with guidelines for Epsilon, Max Ratio, and SPC forces and moments)
  • Stiffness Matrix Equilibrium Check
  • Rigid Body Displacements
  • Modal Identification
  • Thermal Test Cases

Examples from current projects at JPL, such as the Galileo spacecraft and the Wide Field/Planetary Camera for the Space Telescope, will be utilized to describe the implementation of these methods.

DETERMINATION OF STRUCTURAL DYNAMIC RESPONSE SENSITIVITY TO MODAL TRUNCATION (Acrobat 1.35MB) #1086,15 pgs.
Bruce D. Gallaher--General Dynamics Space Systems Division, San Diego, California

ABSTRACT: Current structural analysis methods employ large finite element models to simulate the dynamic behavior of complex systems. These models contain thousands of physical degrees of freedom and consequently, are too cumbersome and inefficient for many analytical purposes. One technique used to produce more manageable models is the mathematical transformation of the physical degrees of freedom into a set of independent modal degrees of freedom. This modal data may then be truncated to reduce the problem size an, therefore, the cost of the analysis. The trade-off for reduced problem size is a loss in accuracy of the physical responses recovered from the model. This paper investigates the modal truncation sensitivity of transient responses which have been recovered using the mode displacement method. A new MSC/NASTRAN DMAP procedure which calculates the modal truncation sensitivity of these responses has been developed. Examples illustrate how this procedure may be used to determine if adequate modal data has been retained to produce accurate responses.

EXPERIENCES WITH SOLUTION 66 IN MSC/NASTRAN (Acrobat 947K) #1186, 12 pgs.
Archie E. NI, Sam V. Sundaram, Dennis J. Dubbs--The Goodyear Tire & Rubber Company, Akron, Ohio

Nonlinear analysis is finding its way into the everyday engineering environment for a variety of reasons including durability, material optimization, and cost effectiveness. There are several solution sequences available in MSC/MASTRAN for nonlinear analysis including SOL64 and SOL66. SOL64 is for geometric nonlinearity only, whereas SOL66 can handle both material and geometric nonlinearity. Also, SOL66 provides a number of attractive features not available in SOL64. Therefore, with SOL66. This paper discusses the authors' hands on experience with some of the features of SOL66.

APPLICATION OF MSC/NASTRAN AND ADS/NASOPT TO NOISE TRANSMISSION PROBLEMS
 (Acrobat 1.56MB) #1286, 19 pgs.
Warren C. Gibson--CSA Engineering, Inc., Gary Vanderplaats, Hiro Miura--Engineering Design Optimization, Inc., Santa Barbara, California

ABSTRACT: This paper addresses the problem of noise transmission from rotating machinery through a support structure to a foundation. The problem is attacked using dynamic finite element analysis with MSC/NASTRAN and optimization with ADS/NASOPT. First, the structure is automatically redesigned so as to drive resonant frequencies away from rotating frequencies. Then, a method is developed and illustrated for calculating the sensitivities of complex steady-state displacements to small changes in design variables. This information is passed to ADS/NASOPT so that it can redesign the structure to minimize the dynamic response directly. The methods are applied to a demonstration problem.

A MODELING STRATEGY FOR ANALYSIS OF OPTOMECHANICAL SYSTEMS (Acrobat 1.13MB) #1386, 12 pgs.
Alson E. Hatheway, Inc.--Consulting Engineers, Pasadena, California

ABSTRACT: The interactions between optical and mechanical phenomena are becoming more important to the optics industry. In many cases the optical performance of systems is limited by the ability of the structural system to maintain the appropriate geometry. It, therefore, becomes important to quantify the interactions between the structural system and the electromagnetic waves that transit the optics. This paper compares optical and structural analysis procedures and describes a modeling strategy for including optical phenomena in structural finite element models

MSC/NASTRAN IMPLEMENTATION OF COUPLED STRUCTURAL-ACOUSTIC RESPONSE FOR AIRCRAFT CABIN NOISE PREDICTION (Acrobat 1.34MB) #1486, 26 pgs.
A.Mera, T.F. Yantis--Boeing Computer Services, G. Sengupta, A. Landmann--Boeing Commercial Airplane Company

ABSTRACT: Low frequency noise transmission into an aircraft cabin (airborne and structure-borne) is becoming an increasing factor for advanced propeller powered aircraft. Analysis of this problem with finite element methods requires coupling the motion of a flexible structure (fuselage) with the pressure in the acoustic volume (cabin interior). The matrix formulation takes advantage of certain underlying similarities between the structural and acoustic equations and solves the 3-D couple structural-acoustic problem for free and forced vibrations. In this presentation, the basic principles of this method will be outlined, and results will be presented to illustrate its potential.

AN EFFICIENT STATIC CORRECTION ALGORITHM WITH APPLICATION TO THE HYDRODYNAMIC LOADING OF THIN SHELL STRUCTURES (Acrobat 820K) #1586, 14 pgs.
J.R. Fitch--General Electric Company, San Jose, California

ABSTRACT: An important class of design problems in the commercial nuclear power industry is concerned with the hydrodynamic loading of thin shell structures which form the boundary of a pool of water called the suppression pool. The purpose of the suppression pool is to condense high pressure steam released from the reactor pressure vessel during abnormal operating transients or postulated accident conditions. When these events occur, the steam condensation is preceded by the clearing of water and air under high pressure from within the piping connecting the pressure vessel to the suppression pool. The clearing of the water and air and the subsequent steam condensation produce transient pressure disturbances in the pool which are transmitted to the boundary. The response of the boundary structure, and it's attached piping and equipment, to these loads is an important consideration in the design evaluation of the suppression pool system.

HOW INTEGRATED SYSTEMS WILL HELP INCREASE THE PRODUCTIVITY OF ANALYSIS
(Acrobat 1.0MB) #1686, 10 pgs.
Raj Gohil--Allied-Bendix Aerospace, Teterboro, New Jersey

ABSTRACT: With the cost of computing coming down, CAD/CAM is proliferating, even down to personal computers. The entry of geometry has always been the most time consuming and uninteresting part of any engineering analysis. But now the geometry is available on CAD/CAM systems. To increase the productivity of engineering analysis, industry will have to develop integrated systems with database management capabilities. Pre-/postprocessors will play a vital role in cutting down time to enter data and interpret results respectively. The bottom line is that integrated systems will surely increase the productivity of engineering analysis.

MANAGING DISTRIBUTED POWER ON AN APOLLO SYSTEM (Acrobat 1.87MB) #1786, 27 pgs.
Glenn H. Stalker--A.O. SMITH Data Systems, Inc.

ABSTRACT: An earlier MSC/NASTRAN User's Conference paper described Apollo MSC/NASTRAN use on a minimum-Investment, single-node DN420. This paper describes a multi-node, state-of-the-art network of Apollo microcomputers, printers, color plotters, auxiliary storage disks, and tape drive. Modern finite element pre- and post-processing software for magnetic, structural, thermal, and CAD applications is described.

OVERVIEW OF THE NEW MSC/NASTRAN EXECUTIVE SYSTEM (Acrobat 529K) #1886, 9 pgs.
D.V. Wallerstein--The MacNeal-Schwendler Corporation

ABSTRACT: The rapid increase in the capabilities of computers has enabled the engineering community to solve larger and more complex problems. The rapid increase in computer types and environments has enabled the engineering community to best suit their tasking requirements for both price and performance. These advantages have come, however, not without a price. The penalty involved is the increase in data management requirements and the handling of data distribution.

Also, advances in engineering technology has expanded the horizons of what is feasible for inclusion into MSC/NASTRAN. Thus MSC must now concern itself with a many faceted integration of engineering disciplines such as design optimization.

The new executive system of MSC/NASTRAN addresses the problems of data management and distribution and the integration of engineering disciplines.

SHAPE OPTIMAL DESIGN ON AN ENGINEER WORKSTATION (Acrobat 3.26MB) #1986, 38 pgs.
C. Fleury, D. Liefooghe--University of California at Los Angeles, Los Angeles, California

ABSTRACT: Shape optimal design of two-dimensional structures discretized in finite elements is investigated with emphasis on creating an interactive Computer Aided Design capability. The paper will first provide a short description of the approach followed to create an appropriate geometric model, involving a relatively small number of design variables. Next the important question of how to perform the sensitivity analysis is discussed. A general procedure is proposed, that takes advantage of the parametric modeling concepts used to create the design model. The sensitivity analysis can then be readily accomplished by a semi-analytical approach, i.e., a finite difference approximation of the stiffness matrix is employed at the element level. The numerical solution to the shape optimal design problem is obtained by resorting to an efficient optimizer based on the convex linearization method.

A two-dimensional pre- and post-processing module is described, which is aimed at performing interactive shape optimal design on an engineering workstation. This module exhibits some innovative visualization techniques that should highly facilitate the task of the designer. Examples of application to classical shape optimal design problems are offered to illustrate the various functions of the new interactive optimization system. Although the current capability is restricted to simple 2-D structures, it is based upon very general concepts that could be readily implemented in general purpose finite element systems such as MSC/NASTRAN.

SENSITIVITY AND OPTIMIZATION OF COMPOSITE STRUCTURES USING MSC/NASTRAN
(Acrobat 1.64MB) #2086, 30 pgs.
Gopal K. Nagendra--The MacNeal-Schwendler Corporation, Claude Fleury--Consultant

ABSTRACT: Design Sensitivity Analysis for composites will soon be available in MSC/NASTRAN. The design variables for composites can be lamina thicknesses, orientation angles, material properties or a combination of all three. With the increasing use of composites in aerospace and automotive industries, this general camability can be used in its own right for carrying out sensitivity analysis of complicated real life structures.

As part of a research effort, the sensitivity analysis has been coupled with a general purpose optimizer. This preliminary version of the optimizer is capable of dealing with minimum weight structural design with a rather general design variable linking capability at the element level or system level. Only sizing type of design variables (i.e. lamina thicknesses) can be handled by the optimizer.

Test cases have been run and validated by comparison with independent Finite Element packages. The linking of Design Sensitivity capability for composites in MSC/NASTRAN with an optimizer would give designers a powerful automated tool to carry out practical optimization design of real life complicated composite structures.

MSC/NASTRAN TRANSIENT THERMAL AND THERMAL STRESS ANALYSIS OF A SURFACE MOUNTED CHIP CAPACITOR (Acrobat 582K) #2186, 12 pgs.
Erin L. Epping--A.O. Smith Data Systems Company

ABSTRACT: Two recent MSC/NASTRAN Users' Conference papers (1, 2)* discussed steady-state thermal analysis of surface mounted chips in automotive ignition systems. This paper applies MSC/NASTRAN transient thermal (SOL 89) and thermal stress (SOL 61) analyses to surface mounted chips. Possible temperature gradients and/or thermal stress due to thermal expansion coefficient mismatch in the assembly are investigated. Results are summarized graphically to evaluate design iterations.

EFFICIENT USE OF COMPONENT MODE SYNTHESIS USING IMAGE SUPERELEMENTS APPLIED TO DYNAMIC ANALYSIS OF CRANKSHAFT (Acrobat 1.45MB) #2286, 27 pgs.
Minoru Kubota--Ishikawajima-Harima Heavy Industries Co., Ltd., Tokyo and Yokohama, Japan

ABSTRACT: Calculations based on large finite element solid models of actual crankshaft system are indispensable to vibration analysis of the crankshaft system of long-stroke marine diesel engines, but limitation to computer capacity or to computing time preclude analysis by conventional method. The present study covers an attempt at utilizing NASTRAN image superelements and component mode synthesis, with application of the restart function, for analyzing the modal frequency response of pilot and large actual-size models. The computed results are compared with measurements made on actual ship, to verify the functional validity and practical accuracy of NASTRAN applied in this mode. This report presents an illustrative example of analysis applied to a pilot model, undertaken to ensure smooth implementation of full-scale calculations on large actual-size model.

SUPERELEMENT PLANNING, DATA MANAGEMENT, AND MULTIPLE BOUNDARY CONDITIONS (Acrobat 2.30MB), #2386, 47 pgs.
Robert F. Cooke--Boeing Computer Services Company, Tukwila, Washington

This paper discusses three critical issues affecting finite element method (FEM) analysis of large NASTRAN models using Superelements: planning, data base management, and multiple boundary conditions. Significant progress has been made in each of these areas which in turn provides project management with greatly improved control, visibility, and efficiency (reduced analysis cost). A data base management modification is presented which reduces long-time disk requirements by 80% and facilitates combining subcases. A strategy and DMAP for combing subcases is presented. A Superelement spreadsheet is presented which displays on one sheet of paper the Superelement plan, bookkeeping information, and the implementation status of a multi-run job. This spreadsheet is the key to understanding the interrelationship between jobs, data bases, data base sets, disk files, magnetic tapes, SEID, and SEID operation. This visibility is required for planing, execution, restarting, and error analysis.