Finite element analysis in a minicomputer/mainframe environment

Design considerations were evaluated for general purpose finite element systems to maximize performance when installed on distributed computer hardware/software systems. It is shown how the features of current minicomputers complement those of a modular implementation of the finite element method for increasing the control, speed, and visibility (interactive graphics) in solving structural problems at reduced cost. The approach used is to implement a finite element system in a distributed computer environment to solve structural problems and to explore alternatives in distributing finite element computations

CSM parallel structural methods research

Parallel structural methods, research team activities, advanced architecture computers for parallel computational structural mechanics (CSM) research, the FLEX/32 multicomputer, a parallel structural analyses testbed, blade-stiffened aluminum panel with a circular cutout and the dynamic characteristics of a 60 meter, 54-bay, 3-longeron deployable truss beam are among the topics discussed

Rapid solution of large-scale systems of equations

The analysis and design of complex aerospace structures requires the rapid solution of large systems of linear and nonlinear equations, eigenvalue extraction for buckling, vibration and flutter modes, structural optimization and design sensitivity calculation. Computers with multiple processors and vector capabilities can offer substantial computational advantages over traditional scalar computer for these analyses. These computers fall into two categories: shared memory computers and distributed memory computers. This presentation covers general-purpose, highly efficient algorithms for generation/assembly or element matrices, solution of systems of linear and nonlinear equations, eigenvalue and design sensitivity analysis and optimization. All algorithms are coded in FORTRAN for shared memory computers and many are adapted to distributed memory computers. The capability and numerical performance of these algorithms will be addressed

An evaluation of superminicomputers for thermal analysis

The use of superminicomputers for solving a series of increasingly complex thermal analysis problems is investigated. The approach involved (1) installation and verification of the SPAR thermal analyzer software on superminicomputers at Langley Research Center and Goddard Space Flight Center, (2) solution of six increasingly complex thermal problems on this equipment, and (3) comparison of solution (accuracy, CPU time, turnaround time, and cost) with solutions on large mainframe computers

An evaluation of superminicomputers for thermal analysis

The feasibility and cost effectiveness of solving thermal analysis problems on superminicomputers is demonstrated. Conventional thermal analysis and the changing computer environment, computer hardware and software used, six thermal analysis test problems, performance of superminicomputers (CPU time, accuracy, turnaround, and cost) and comparison with large computers are considered. Although the CPU times for superminicomputers were 15 to 30 times greater than the fastest mainframe computer, the minimum cost to obtain the solutions on superminicomputers was from 11 percent to 59 percent of the cost of mainframe solutions. The turnaround (elapsed) time is highly dependent on the computer load, but for large problems, superminicomputers produced results in less elapsed time than a typically loaded mainframe computer

The finite element machine: An experiment in parallel processing

The finite element machine is a prototype computer designed to support parallel solutions to structural analysis problems. The hardware architecture and support software for the machine, initial solution algorithms and test applications, and preliminary results are described

Community preceptors' views of a required third-year family medicine clerkship

BACKGROUND: Previous studies documented the importance of family medicine clerkships to medical student education and to the potential costs of precepting students borne by community physicians. But what are the physicians' views of their experience, their perceived needs for teaching, and sources of satisfaction from the preceptor role? OBJECTIVES: To explore preceptors' views of a required, third-year family medicine clerkship, focusing on satisfaction with the teaching experience, effect of having students in the practice, and concerns about continuing as a preceptor. METHODS: Preceptors from 38 private practices were asked to participate in a 15-minute telephone survey, using a semistructured interview format. RESULTS: Thirty-five physicians (92%) agreed to participate and 33 of the 35 primary preceptors were interviewed. Of those interviewed, 29 (88%) indicated a positive teaching experience, and 31 (94%) desired to continue precepting. Intangible rewards (eg, love of teaching or "giving back" to the specialty of family medicine) far out-weighed tangible rewards (eg, dinners or letters of appreciation) with regard to their desire to precept. Continued satisfaction with precepting seemed to be affected by loss of revenue to the practice, longer work hours, ability to effectively manage time and patient load, and need for additional educational resources and equipment. CONCLUSIONS: Intrinsic rewards seem to be a key factor in the physicians' decision to precept. Moreover, to reinforce the preceptor's continued desire to precept, faculty development, provision of educational tools and resources, and remuneration may be necessary. Preceptors should be asked routinely about their needs, and special programs of support should be offered

RF switch positioner for communications satellite network

The RF switch positioner is a simple, lightweight, redundant positioning mechanism used to reconfigure the antenna beam on the INTELSAT VI satellite. It simultaneously rotates approximately 100 squareax waveguide switches through a full 360 deg. The RF switch positioner has been space qualified and has performed to expectations in conjunction with the feed networks in range testing

Automatic differentiation for design sensitivity analysis of structural systems using multiple processors

An automatic differentiation tool (ADIFOR) is incorporated into a finite element based structural analysis program for shape and non-shape design sensitivity analysis of structural systems. The entire analysis and sensitivity procedures are parallelized and vectorized for high performance computation. Small scale examples to verify the accuracy of the proposed program and a medium scale example to demonstrate the parallel vector performance on multiple CRAY C90 processors are included