Early Use and Continuing Development of NASTRAN

The first components of NASTRAN became operational at Goddard in May 1968. Distribution to other Centers, training, and a debugging period followed through 1969 and into 1970.[816] With completion of the initial devel­opment, "the management of NASTRAN was transferred to the Langley Research Center. The NASTRAN Systems Management Office (NSMO) was established in the Structures Division at Langley October 4, 1970.”[817] Initial public release followed just 1 month later, in November 1970.

NSMO responsibilities included:[818]

• Centralized program development (advisory committees).

• Coordinating user experiences (bimonthly NASTRAN Bulletin and annual Users’ Colloquia).

• System maintenance (error correction and essential improvements).

• Development and addition of new capability.

• NASTRAN-focused research and development (R&D).

The actual distribution of NASTRAN to the public was handled by the Computer Software Management and Information Center (COSMIC), NASA’s clearinghouse for software distribution (which is described in a subsequent section of this paper). The price at initial release was $1,700, "which covers reproducing and supplying the necessary system tapes and documentation.”[819] Documentation was published in four vol­umes, each with a distinct purpose: one for users, one for programmers who would be involved in maintenance and subsequent development, a theory manual, and finally a volume of demonstration problems. (The 900-page user’s manual could be obtained from COSMIC for $10, if purchased separately from the program itself. The author assumes that the other volumes were similarly priced.)[820]

CATEGORY	COMPUTERS
NASA CENTERS
DOC
OTHER GOV T
8
AEROSPACE
AIRCRAFT
COMPUTER CORF	MANUFACTURING ENGR CONSIT AUTO UNIVERSITIES
OTHERS

2,272 USERS

NASTRAN user community profile in 1974. NASA.

Things were happening quickly. Within the first year after public release, NASTRAN was installed on over 60 machines across the United States. There were urgent needs requiring immediate attention. "When NSMO was established in October 1970, there existed a dire need for maintenance of the NASTRAN system. With the cooperation of Goddard Space Flight Center, an interim maintenance contract was negotiated with Computer Sciences Corporation through a contract in effect at GSFC. This contract provided for the essential function of error cor­rection until a contract for full time maintenance could be negotiated through an open competition. The interim maintenance activity was restricted to the correction of over 75 errors reported to the NSMO, together with all associated documentation changes. New thermal bend­ing and hydroelastic elements previously developed by the MacNeal- Schwendler Corporation under contract to GSFC were also installed. Levels 13 and 14 were created for government testing and evaluation. The next version of NASTRAN to be released to the public. . . will be built upon the results of this interim maintenance activity and will be designated Level 15,” according to a status report to the user community in 1971.[821]

In June 1971, the contract for full-time maintenance was awarded to MacNeal Schwendler Corporation, which then opened an office near Langley. A bug reporting and correction system was established. Bell Aerospace Company received a contract to develop new elements and a thermal analysis capability. Other efforts were underway to improve efficiency and execution time. A prioritized list of future upgrades was started, with input from all of the NASA Centers. However, for the time being, the pace of adding new capability would be limited by the need to also keep up with essential maintenance.[822]

By 1975, NASTRAN was installed on 269 computers. The estimated composition of the user community (based on a survey taken by the NSMO) is illustrated here.

By this time, the NSMO was feeling the pressure of trying to keep up with maintenance, bug fixes, and requested upgrades from a large and rapidly growing user community. There was also a need to keep up with changing hardware technology. Measures under consideration included improvements to the Error Correction Information System (ECIS); more user involvement in the development of improvements (although this would also require effort to enforce coding standards and interface requirements, and to develop procedures for verification and implementation); and a price increase to help support the NSMO’s maintenance costs and also possibly recoup some of the NASTRAN development costs. COSMIC eventually changed its terms for all soft­ware distribution to help offset the costs of maintenance.

An annual NASTRAN Users’ Colloquium was initiated, the first of which occurred approximately 1 year after initial public release. Each Colloquium usually began with an overview from the NSMO on NASTRAN status, including usage trends, what to expect in the next release, and planned changes in NASTRAN management or terms of distribution. Other papers covered experiences and lessons learned in deployment, installation, and training; technical presentations on new types of elements or new solution capabilities that had recently been, were being, or could be, implemented; evaluation and comparison of NASTRAN with test data or other analysis methods; and user experiences and applications. (The early NASTRAN Users’ Colloquia proceedings were available from the National Technical Information Service for $6.)

The first Colloquia were held at Langley and hosted by the NSMO staff. As the routine became more established and the user community grew, the Colloquia were moved to different Centers and cochaired, usu­ally by the current NSMO Manager and a representative from the host­ing Center. There were 21 Users’ Colloquia, at which 429 papers were presented. The breakdown of papers by contributing organization is shown here.(Note: collaborative papers are counted under each contrib­uting organization, so the sum of the subtotals exceeds the overall total.)

ORGANIZATIONS PRESENTING PAPERS AT NASTRAN USERS’ COLLOQUIA
TOTAL PAPERS	429
NASA SUBTOTAL:	91
Goddard	33
Langley	35
Other NASA	23
INDUSTRY SUBTOTAL:	274
Computer and software companies	104
Aircraft and spacecraft industry	1 16
Nonaerospace industry	54
UNIVERSITIES:	26
OTHER GOVERNMENT SUBTOTAL:	91
Air Force	10
Army	15
Navy	61
National Laboratories	5

Computing companies were typically involved in theory, modeling technique, resolution of operational issues, and capability improvements (sometimes on contracts to NASA or other agencies), but also collab­orated with "user” organizations assisting with NASTRAN application to problems of interest. All participants were actively involved in the improvement of NASTRAN, as well as its application.

Major aircraft companies—Boeing, General Dynamics, Grumman, Lockheed, McDonnell-Douglas, Northrop, Rockwell, and Vought—were frequent participants, presenting a total of 70 papers. Smaller aerospace companies also began to use NASTRAN. Gates Learjet modeled the Lear 35/36 wing as a test case in 1976 and then used NASTRAN in the design phase of the Lear 28/29 and Lear 55 business jets.[823] Beechcraft used NASTRAN in the design of the Super King Air 200 twin turboprop and the T-34C Mentor military trainer.[824] Dynamic Engineering, Inc., (DEI) began using NASTRAN in the design and analysis of wind tunnel models in the 1980s.[825]

Nonaerospace applications appeared almost immediately. By 1972, NASTRAN was being used in the automotive industry, in architectural engineering, by the Department of Transportation, and by the Atomic Energy Commission. The NSMO had "received expressions of interest in NASTRAN from firms in nearly every West European country, Japan, and Israel.”[826] That same year, "NASTRAN was chosen as the principal analytical tool” in the design and construction of the 40-story Illinois Center Plaza Hotel building.[827]

Other nonaerospace applications included:

• Nuclear power plants.

• Automotive industry, including tires as well as primary structure.

• Ships and submarines.

• Munitions.

• Acoustic and electromagnetic applications.

• Chemical processing plants.

• Steam turbines and gas turbines.

• Marine structures.

• Electronic circuitry.

B. F. Goodrich, General Motors, Tennessee Eastman, and Texas Instruments were common presenters at the Colloquia. Frequent Government participants, apart from the NASA Centers, included the David Taylor Naval Ship Research & Development Center, the Naval Underwater Systems Cener, the U. S. Army Armament Research & Development Command, and several U. S. Army arsenals and laboratories.[828]

Technical improvements, too numerous to describe them all, were continually being made. At introduction (Level 12), NASTRAN offered linear static and dynamic analysis. There were two main classes of new capability: analysis routines and structural elements. Developments were often tried out on an experimental basis by users and reported on at the Colloquia before being incorporated into standard NASTRAN. Evaluations and further improvements to the capability would typically follow. In addi­tion, of course, there were bug fixes and operational improvements. A few key developments are identified below. Where dates are given, they rep­resent the initial introduction of a capability into standard NASTRAN, not to imply full maturity:

• Thermal analysis: initial capability introduced at Level 15 (1973).

• Pre – and post-processing: continuous.

• Performance improvements: continuous.

• Adaptation to new platforms and operating systems: con­tinuous. (The earliest mention the author has found of NASTRAN running on a PC is 1992.[829])

• New elements: continuous. Level 15 included a dummy structural element to facilitate user experimentation.

• Substructuring: the decomposition of a larger model into smaller models that could be constructed, manipulated, and/or analyzed independently. It was identified as an important need when NASTRAN was first introduced.

Initial substructuring capability was introduced at Level 15 in 1973.

• Aeroelastics and flutter: studies were conducted in the early 1970s. Initial capability was introduced in Level 16 by 1976. NASTRAN aeroelastic, flutter, and gust load anal­ysis uses a doublet-lattice aerodynamic method, which approximates the wing as an initially flat surface for the aerodynamic calculation (does not include camber or thickness). The calculation is much simpler than full – fledged computational fluid dynamics (CFD) analysis but neglects many real flow effects as well as configuration geometry details. Accuracy is provided by using correc­tion factors to match the static characteristics of the dou­blet-lattice model to higher fidelity data from flight test, wind tunnel test, and/or CFD. One of the classic references on correcting lifting surface predictions is a paper by J. P. Giesing, T. P. Kalman, and W. P. Rodden of McDonnell – Douglas, on contract to NASA, in 1976.[830]

• Automated design and analysis: automated fully stressed design was introduced in Level 16 (1976). Design automa­tion is a much broader field than this, however, and most attempts to further automate design, analysis, and/or opti­mization have taken the form of applications outside of, and interfacing with, NASTRAN. In many industries, auto­mated design has become routine; in others, the status of automated design remains largely experimental, primarily because of the inherent complexity of design problems.[831]

• Nonlinear problems: geometric and/or material. Geometric nonlinearity is introduced, for example, when displacements are large enough to change the geomet­ric configuration of the structure in significant ways. Material nonlinearity occurs when local stresses exceed the linear elastic limit. Applications of nonlinear analy­sis include engine hot section parts experiencing regions of local plasticity, automotive and aircraft crash simula­tion, and lightweight space structures that may experi­ence large elastic deformations—to name a few. Studies and experimental implementations were made dur­ing the 1970s. There are many different classes of non­linear problems encompassed in this category, requir­ing a variety of solutions, many of which were added to standard NASTRAN through the 1980s.