362.fma3d (FMA-3D)
Samuel W. Key (swkey@worldnet.att.net)
For current version and availability information, please contact:
Samuel W. Key
dba KEY Associates
1851 Tramway Terrace Loop NE
Albuquerque, NM 87122
USA
Telephone and Fax: (505) 856-1488
This information is current as of October 1999.
Mechanical Response Simulation
FMA-3D is a finite element method program designed to simulate the inelastic, transient dynamic response of three-dimensional solids and structures subjected to impulsively or suddenly applied loads. As an explicit code, the program is appropriate for problems where high rate dynamics or stress wave propagation effects are important. In contrast to programs using implicit time integration algorithms, the program uses a large number of relatively small time steps, with the solution for the next configuration of the body being explicit (and inexpensive) at each step. To further reduce the computational effort, the program has a complete implementation of Courant subcycling in which each element is integrated with the maximum time step permitted by local stability criteria. For simulations that have large differences in element critical time steps over the mesh, very significant savings in execution time are achieved. There are no inherent limits on the size of an analysis model, and storage allocation is dynamic within the code.
The program may be applied to static and quasi-static problems either by using the dynamic relaxation option or by simply applying the external loads slowly and integrating the dynamics equations until all significant transients have died out.
The algorithms and architecture of the program are designed for accuracy and robustness. The solution portion of the program is in a form suitable for cache-based computer hardware architectures. The program is written in Fortran-90 and consists of over 50,000 lines of code and comments. The program's key features include:
The program has a large selection of quality finite elements from which to choose for constructing a model. The element formulations all handle geometric and material nonlinearities and do not lock for incompressible materials. The element library has formulations that include:
To simulate realistically a variety of material behavior, the program has a collection of very practical stress-strain models with well established integration algorithms. The program's library of material models includes:
The SPEC Reference input workload is the simulation of an impulsive load (initial velocity condition) applied to a cylindrical panel (thin shell structure supported by clamped, simply supported, and symmetry boundary conditions). A very fine finite element mesh (a large number of finite elements) is used to obtain a 100 MB RAM-resident data set for the simulation.
The reference data set has 4032000 elements with 4104000 nodal points.
Based on the program's ability to provide edited printer output, only the displacements at two specific nodal points are printed. These two nodal points are at the edge of the impulsive load where the initial velocity conditions are discontinuous and, therefore, the response of the cylindrical panel is initially the most interesting.
Fortran-90
Apart from compiler-specific and machine-specific optimization issues, the only recommended compiler switch for this version of the program for general use is -static.
Key, S. W. and C. C. Hoff, "An Improved Constant Membrane and Bending Stress Shell Element for Explicit Transient Dynamics," Computer Methods in Applied Mechanics and Engineering, Vol. 124, pp 33-47, 1995. DOI