" uJ LANGLEY RESEARCH CENTER 3 1176 00506 2394 NASA Conference Publication 2249 Tenth • , NASTRAN Users" Colloquium Proceedings of a colloquium held at New Orleans, Louisiana May 13-14, 1982 tUlSA NASA Conference Publication 2249 Tenth NASTRAN Users' Colloquium Proceedings of a colloquium held at New Orleans, Louisiana May 13-14, 1982 N_A National Aeronautics and Space Administration ScientificandTechnical InformationBranch 1982 FOREWORD NASTRAN® (NASA STRUCTURAL ANALYSIS) is a large, comprehensive, nonproprietary, general purpose finite element computer code for structural analysis which was developed under NASA sponsorship and became available to the public in late 1970. It can be obtained through COSMIC (Computer Software Management and Information Center), Athens, Georgia, and is widely used by NASA, other government agencies, and industry. NASA currently provides continuing maintenance of NASTRAN® through COSMIC. Because of the widespread interest in NASTRAN®, and finite element methods in general, the Tenth NASTRAN@ Users' Colloquium was organized and held at the Marriott Hotel, New Orleans, May 13-14, 1982. (Papers from previous colloquia held in 1971, 1972, 1973, 1975, 1977, 1978, 1979, and 1980, are published in NASA Technical Memorandums X-2378, X-2637, X-2378, X-2893, X-3278, X-3428, and NASA Conference Publications 2018, 2062, 2131, and 2151.) The Tenth Colloquium provides some comprehensive general papers on the application of finite element methods in engineering, comparisons with other approaches, unique applications, pre- and post-processing or auxiliary programs, and new methods of analysis with NASTRAN®. Individuals actively engaged in the use of finite elements or NASTRAN® were invited to prepare papers for presentation at the Colloquium. These papers are included in this volume. No editorial review was provided by NASA or COSMIC, however, detailed instructions were provided each author to achieve reasonably consistent paper format and content. The opinions and data presented are the sole responsibility of the authors and their respective organizations. iii CONTENTS Page FOREWORD ................................. iii i. OPERATING IN THE AGE OF NASTRAN ................... 1 by Thomas G. Butler (Butler Analyses) 2. RECENT IMPROVEMENTS AND ENHANCEMENTS TO NASTRAN ........... 12 by P. R. Pamidi (Computer Sciences Corporation) 3. RECENT DEVELOPMENTS OF NASTRAN PRE- AND POST-PROCESSORS: RESPONSE SPECTRUM ANALYSIS (RESPAN) AND INTERACTIVE GRAPHICS (GIFTS) ..... 18 by Eric F. Hirt and Gary L. Fox (NKF Engineering Associates, Inc.) 4. AN INTERACTIVE REVIEW SYSTEM FOR NASTRAN .............. 45 by Lawrence L. Durocher (University of Bridgeport) and Andrew F. Gasper (Hamilton Standard) 5. ON THE USE OF HARMONIC EXPANSIONS IN MAGNETIC FIELD PROBLEMS IN NASTRAN ............................... 65 by Myles M. Hurwitz, Delores R. Wallace, and Ernest W. Brooks (David W. Taylor Naval Ship Research and Development Center) 6. IMPROVING A NASTRAN DYNAMIC MODEL WITH TEST DATA USING LINWOOD . 74 by B. H. Ujihara, M. M. Dosoky, and E. T. Tong (Rockwell International) 7. SOLUTION OF AXISYMMETRIC FLUID STRUCTURE INTERACTION PROBLEMS _ WITH NASTRAN ............................. 87 by A. J. Kalinowski and C. W. Nebelung (Naval Underwater Systems Center) 8. LARGE DISPLACEMENTS AND STABILITY ANALYSIS OF NONLINEAR PROPELLER STRUCTURES ............................. 112 by Robert A. Aiello and Christos C. Chamis (NASA Lewis Research Center) 9. PREDICTION OF BEAD AREA CONTACT LOAD AT THE TIRE-WHEEL INTERFACE USING NASTRAN ........................... 133 By C. H. S. Chen (The B.F. Goodrich Company) i0. ON ELASTIC-PLASTIC ANALYSIS OF AN OVERLOADED BREECH RING USING NASTRAN ............................... 143 by P. C. T. Chen (U. S. Army Armament Research and Development Command Benet Weapons Laboratory) ii. FINITE ELEMENT SOLUTION OF TORSION AND OTHER 2-D POISSON EQUATIONS . 153 by Gordon C. Everstine (David W. Taylor Naval Ship Research and Development Center) 12. A NEW CAPABILITY FOR ELASTIC AIRCRAFT AIRLOADS VIA NASTRAN ..... 165 by Hugh C. Briggs and Lance E. Chrisinger (Air Force Institute of Technology) 13. NASTRAN ON THE HEP ......................... 187 by W. Keith Brown (RPK Corporation) 14. THE USAGE OF SUBSTRUCTURING ANALYSES IN THE GET AWAY SPECIAL (GAS) PROGRAM .............................. 204 by Nelson J. Ferragut (NASA Goddard Space Flight Center) 15. USING NASTRAN TO SOLVE SYMMETRIC STRUCTURES WITH NONSYMMETRIC LOADS . 216 by Thomas G. Butler (Butler Analyses) 16. EVALUATION AND REDUCTION OF ERRORS INDUCED BY THE GUYAN TRANSFORMATION ........................... 233 by Gary L. Fox (NKF Engineering Associates, Inc.) 17. ON RESTARTS IN NASTRAN ....................... 249 by P. R. Pamidi and M. M. Lin (Compute r Sciences Corporation) OPERATING IN THE AGE OF NASTRAN T. G. Butler, BUTLER ANALYSES NASTRAN was born at a time when technology was advancing rapidly. It is interesting to reflect on conditions prevailing then. At year zero in the age of NASTRAN (1964) the role of analysis in mechanical design was to make rough estimates. Testing was relied on for proof of design. Analysts were known as intellectual eggheads, but test people were called practical, down-to-earth types. Popular analytical methods at the time were Hardy-Cross and Hrenikoff for statics; for shaft vibrations they were Mykelstad and Holzer. Analog computers were the most advanced analytical tools. Electrical engineers were doing remarkable things with network analyzers, and similar success was enjoyed with hydraulic networks. Finite elements had only recently appeared, and all programs were company-proprietary and limited in solution range. Aerospace companies dominated the finite element scene. The workhorse computer was the IBM 7094, but third-generation computers were developing a competi- tion between IBM 360, CDC 6600, and UNIVAC ll08. Time sharing was on the drawing boards. Terminal inputs used card readers. Universities were preoccupied with solving boundary value problems, but a small nucleus of about 20 professors worldwide were taking finite elements seriously. NASA's Office of Advanced Research and Technology (OART) under Dr. Raymond Bisplinghoff sponsored a considerable amount of research in the area of flight structures through its operating centers. Representatives from the centers who managed research in structures convened annually to exchange ideas. I was one of the representatives from Goddard Space Flight Center at the meeting in January 1964. I detected a pattern that seemed to need redirection. Center after center described research programs to improve analysis of structures. Shells of different kinds were logical for NASA to analyze at the time because rockets are shell- i like. Each research concentrated on a different aspect of shells. Some were closed with discontinuous boundaries. Other shells had cutouts. Others were noncircular. Others were partial spans of less than 360°• This all seemed quite worthwhile if the products of the research resulted in exact closed-form solutions. However, all of them were geared toward making some simplifying assumption that made it possible to write a computer program to give numerical solutions for their behavior. The popular phrase at the time was "solutions to within engineering accuracy." Each of these computer programs required data organization different from every other program; e.g., they were not oompatible. Each was intended for exploring localized conditions rather than complete shell-like structures, such as a whole rocket. My reaction to these programs was that if the end products were all accurate only to within engineering accuracy, technology was currently available to give engineering solu- tions to not just localized shells but to whole, highly varied structures. The method was finite elements. I proposed that finite elements be used for obtaining engineering solutions and research be upgraded to making fewer simplifications and aim for closed-form solutions, which are always needed. This caused a furor, but Headquarters responded by setting up a committee to investigate the subject of numerical analysis of structures. The ad hoc committee was composed of a representative from each NASA Center. There was some change of personnel before the committee's work was completed. Names of members were: Center Representative Ames Dick Beam and Perry Polentz Flight Dick Rosecrans Goddard Tom Butler (Chairman) and Pete Smidinger JPL Mickey Alper and Bob Bamford Langley Herb Cunningham Lewis Bill Scott and Jim McAleese Manned Tom Modlin Marshall Bob McComas The committee was commissioned to investigate what the state of analysis was in the aerospace industry at the time. We were to determine if analog computing should be promoted more or if the finite elements method was more suited to NASA's analyses. We were to try to find an existing finite element program of a quality that would be worth recommending to all NASA Centers. We wanted to visit all aerospace companies, but under out-time and budgetary constraints we were obliged to limit ourselves. We visited Boeing in Seattle, Lockheed in Burbank, Douglas in Santa Monica, Philco in Pasadena, North American in Columbus, Bell in Buffalo, and Martin in Baltimore. All these companies were extremely cooperative and candid. At the completion of the investigation we felt assured that there was enough information at hand to come to a consensus. The committee's recommendation to Dr. Bisplinghoff, Mel Rosche, and Doug Michel at NASA Headquarters was