Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 87
Page 87 Appendix B Computer Code Abstracts Provided by Code Developers ALE3D Lawrence Livermore National Laboratory ALE3D is a three-dimensional finite-element code that utilizes arbitrary Lagrangian-Eulerian techniques to simulate fluid dynamics and elastic-plastic response on an unstructured mesh. The grid may consist of arbitrarily connected hexahedra, beam, and shell elements. The mesh can be constructed from disjoint blocks of elements which interact at the boundaries via slide surfaces. The basic computational cycle consists of a Lagrangian step followed by an advection step. In the advection step, nodes in selected materials can be relaxed either to relieve distortion or to improve accuracy and efficiency. ALE3D thus has the option of treating structural members in a Lagrangian mode and treating materials which undergo large distortions in a ALE mode, all within the same mesh/problem configuration. The code has a range of equation-of-state and constitutive descriptions that are appropriate for modeling hydrodynamic shock phenomena. Several options are available for describing explosive detonations. ALE3D is currently being applied to a number of studies involving the effects of explosive events. ALE3D has been distributed under a collaborative licensing agreement. At the request of the U.S. Department of Defense, it is being treated as an export-controlled code. The code currently runs on essentially all workstations and Crays. A graphics post-processor, MESHTV, is provided with the code. Mesh generation requires INGRID or TRUEGRID or any other mesh generator that can provide an output file in DYNA3D format.
OCR for page 88
Page 88 ALEGRA Sandia National Laboratories ALEGRA is a solid dynamics code developed at Sandia National Laboratories for modeling the near-field and far-field transient response of complex bodies to explosions, impacts, or energy deposition. It combines the structural analysis algorithms found in Sandia's Lagrangian PRONTO code with the large deformation shock physics algorithms found in Sandia's Eulerian CTH code. This allows ALEGRA to accurately model the near-field large deformations of an explosion with an Eulerian mesh and the far-field structural response with a Lagrangian mesh. ALEGRA can model both three-dimensional and two-dimensional problems. It has simulated several problems including the response of containment vessels to explosive loading, the stresses in a machine tool cutting bit, and the transient response of an explosively loaded, fluid-filled storage compartment. ALEGRA uses an explicit, time-stepping finite-element formulation and an arbitrary connectivity mesh composed of three-dimensional hexahedral and shell elements or two-dimensional quadrilateral elements. ALEGRA was designed using object-oriented software engineering concepts and is written in C++, C, and FORTRAN. ALEGRA runs on workstations and massively parallel computers. Reference: Budge, K.G., and J.S. Peery. 1993. RHALE: a MMALE shock physics code written in C++. International Journal of Impact Engineering 14:107–120. BLASTX Science Applications International Corporation BLASTX (version 3.0) code calculates the propagation of blast shock waves and detonation product gases in multiroom structures. The code provides predictions of the pressure-time and temperature-time histories in these structures. The 3.0 version includes: (1) a variety of room shapes that may be used throughout a structure, (2) an interactive menu-driven input module, (3) an enhanced version of the burning, venting, and wall-failure models from the Naval Surface Warfare Center INBLAST code, (4) failure models using the total shock and quasi-static gas pressure on a wall, (5) heat conduction to walls, (6) a more accurate model of shock propagation through openings, and (7) modeling of blast-effects within and outside of explosive storage magazines. The code uses dynamic memory allocation so that structures ranging from a single room to many rooms may be treated. Reference: SAIC. 1994. International Blast and Thermal Environment for Internal and External Explosions: A User's Guide for the BLASTX Code, Version 3.0. (SAIC 405-94-2).
OCR for page 89
Page 89 CTH (shock physics) Sandia National Laboratories CTH is a multimaterial, large deformation, strong shock-wave, solid mechanics code developed at Sandia National Laboratories. CTH has models for multiphase, elastic-viscoplastic, porous, and explosive materials. Three-dimensional rectangular meshes, two-dimensional rectangular and cylindrical meshes, and one-dimensional rectilinear, cylindrical, and spherical meshes are available. It uses second-order accurate numerical methods to reduce dispersion and dissipation and to produce accurate, efficient results. CTH runs on most Unix work-stations and supercomputers. Preprocessing and color graphic postprocessing programs are provided. PCTH is a massively parallel version of the CTH code. It runs on Intel and nCUBE massively parallel computers. It supports only three-dimensional meshes. It is heavily used to model problems much larger than possible with workstation or Cray computers. PCTH has several material models appropriate for strong shock and large deformation calculations. SESAME tabular and analytic equations of state model the nonlinear behavior of materials in the high-pressure regime. SESAME can model solid, liquid, vapor, liquid-vapor, solid-liquid, and solid-solid phase changes. An elastic-perfectly-plastic model with thermal softening is available. The Johnson-Cook, Zerilli-Armstrong, and Steinburg-Guinan viscoplasticity models are available. In addition, the Johnson-Holmquist brittle strength and failure model is available for modeling brittle materials such as ceramic or concrete. High-explosive detonation can be modeled using programmed burn, Lee-Tarver, Forestfire, and a history variable model developed at Sandia. The Jones-Wilkins-Lee analytic and SESAME tabular equations of state can model the high-explosive reaction products. Fracture can be initiated based on pressure or principal stress. A model moves fragments smaller than a computational cell with statistically correct velocity. This model is very useful for analyzing fragmentation experiments and experiments with witness plates. CTH uses an Eulerian solution scheme where the mesh is fixed in space and the material flows through the mesh. CTH uses monotone, second-order convention schemes to flux all quantities between cells. It has a high-resolution material interface capturing scheme that prevents numerical breakup and distortion of material interfaces. These numerical methods reduce the dispersion and dissipation found in first-order accurate Eulerian codes. CTH is written in FORTRAN77 and a small amount of C code. CTH runs on virtually all Unix-based systems such as those from Cray, Sun, Hewlett Packard, SGI, IBM RS6000, DEC/Ultrix, and Convex. PCTH is written in C++, C, and FORTRAN. It runs on Intel and nCUBE massively parallel computers. All variables can be displayed in two- and three-dimension plots and as a function of time with CTH's postprocessing programs. The plots can be displayed on color and monochrome X-windows-based workstations. They can be
OCR for page 90
Page 90 printed on color and black-and-white PostScript printers. CTH is an export-controlled code. Reference: McGlaun, J.M., S.L. Thompson, and M.G. Elrick 1990. CTH: a three-dimensional shock physics code. International Journal of Impact Engineering 10:351–360. DYNA3D Lawrence Livermore National Laboratory DYNA3D, first developed in 1976 and continually updated thereafter, is a nonlinear, explicit finite-element code for analyzing the transient, dynamic response of three-dimensional solids and structures. The code is fully vectorized and is available on several computer platforms. DYNA3D includes solid, shell, beam, and truss elements to allow maximum flexibility in modeling physical problems. Many material models are available to represent a wide range of material behavior, including elasticity, plasticity, composites, thermal effects, and rate dependence. In addition, DYNA3D has a sophisticated contact interface capability, including frictional sliding and single surface contact. Rigid materials provide added modeling flexibility. A material model driver with interactive graphics display is incorporated into DYNA3D to permit accurate modeling of complex material response based on experimental data. Reference: 1989. DYNA3D User's Manual: Nonlinear Dynamic Analysis of Structures in Three Dimensions. UCID-19592, Rev.5. Livermore, California: Lawrence Livermore National Laboratory. EPSA-II Weidlinger Associates, Inc. The EPSA-II code is a finite-element program for the response of shell structures. It is primarily aimed at metallic structures in fluid media and has been used extensively for underwater structures, such as shock loading of submarine hulls. Both small-scale and prototype structure tests have been conducted to validate the program. Reference: Atkatsh, R.S., et al. 1994. EPSA-II Theoretical Guidebook, Rev. G. New York: Weidlinger Associates.
OCR for page 91
Page 91 FLEX (finite-element) Weidlinger Associates, Inc. FLEX is a three-dimensional explicit, time domain finite-element code designed to analyze the response of continua and structures subjected to dynamic or static loads. Weidlinger Associates has developed and supports the code. New revisions are released once or twice a year. The code has been applied to a wide range of problems including geotechnical, seismic-wave propagation, soil-structure interaction, accidental explosion, and weapon effects. The accuracy of the program has been verified against both analytic solutions and other codes. The code contains sophisticated nonlinear constitutive models to represent soil, rock, and reinforced concrete subjected to high-stress environments such as blast loading. Beam, bar, shell, and continuum element types are available for modeling. Both nuclear and conventional explosion pressure functions are included in the code. An embedded scripting language is included to allow the construction of templates for particular classes of problems. These templates allow unsophisticated users to define and run a model by inputing only the key problem parameters. The template generates the grid, computes the solution, and evaluates the results using the expertise of the individual constructing the template. Fully integrated color graphics and PostScript hardcopy allow for all aspects of the model to be displayed at any time during a calculation. On-screen movies can be created and displayed. The code runs on most classes of hardware, including personal computers, Unix workstations and Cray supercomputers. The program and its derivative versions are currently being used by a number of organizations, including governmental agencies, academic institutions, and commercial companies. Reference: Vaughan, D.K., and E. Richardson. 1994. FLEX User's Manual, Version 1-h.4. New York: Weidlinger Associates. FEFLO Science Applications International Corporation The FEFLO family of codes is based on high-order monotonicity, preserving algorithms and the adaptive unstructured grid methodology developed by SAIC and George Mason University. Time-accurate or steady-state solutions for complex geometries with multiple moving bodies are reliably obtained over a wide range of flow regimes. Combined with the configured definition tools, FECAD and FRGEN, highly accurate solutions to real problems are achieved on a time scale compatible with the design cycle. FECAD: Configuration definition for geometry, materials, and boundary conditions. Features include import of surface data (CATIA, CADAM, IGES, BRLCAD); workstation-based interactive mouse-driven modules; surface-oriented object library; mesh generation for fluid or structural dynamics computa-
OCR for page 92
Page 92 tional meshes; functions for translation, rotation, scaling, surface lofting, automatic part merging, and extensive diagnostics. FRGEN: Automatic mesh generation for adaptive unstructured surface and volumetric grids. Features include interactive background grid specification; variable grid-spacing density and stretching; point line and volumetric sources; and extensive grid-quality diagnostics. Executes on mainframes or workstations. FEFLO: Compressible or incompressible Euler and Navier-Stokes codes using either an implicit or explicit formulation. Features include automatic mesh adaptation to physical or geometric features, moving bodies, and equations of state. FEMOVIE: Solution animation allowing for multiple cameras, moving viewer frame, complex viewer trajectories, and zoom/pan. FEPLOT: Complete three-dimensional package for interactive diagnostics including tracers, streamlines, arrows, contours, iso-surfaces, and cut planes of all-fluid conserved and derived quantities. Reference: Baum, J.D., H. Luo, and R. Löhner. 1995. Numerical Simulation of Blast in the World Trade Center. AIAA-95-0085. AIAA 33rd Aerospace Sciences Meeting, Reno, Nevada, January. FOIL Applied Research Associates, Waterways Experiment Station The first-principle code FOIL is an efficient analytic ground-shock prediction code that calculates ground-shock parameters (radial stress, impulse, velocity, displacement, and hoop stress versus time; peak radial stress, impulse, velocity, displacement, and hoop stress versus range; time of arrival of peak and time of initial arrival versus range) due to the detonation of conventional explosives in backfill materials. Predictions for fully coupled bombs are based on analytic fits to first-principle, one-dimensional spherical calculations of a spherical source of 188.8 kg of H6 explosive detonated in 20 backfill materials. The standard explosive is H6; cube-root scaling is employed to allow the use of the equivalent explosive concept to predict for explosives other than H6. A coupling-factor concept is employed to allow for effects of depth of burial less than fully coupled as defined in Army Manual TM5-855-1. The purpose of this code is to provide the Department of Defense community with improved ground-shock prediction techniques for use in decoupled structural analyses for the design of hardened structures. The equations in FOIL are formulated based on the theory of spherical flow fields in locking solids, and the backfill models/properties have been validated by comparisons of calculation results with recent test data. FOIL in turn closely replicates the first-principle calculation results and hence the test data, whereas
OCR for page 93
Page 93 previous empirical-based analytic prediction techniques as defined in the current military design manuals do not. Reference: Windham, J.E., H.D. Zimmerman, and R.E. Wacker. 1993. Improved Ground Shock Predictions for Fully Buried Conventional Weapons. Proceedings of a special session of the Sixth Internal Symposium on the Interaction of Conventional Munitions with Protective Structures, Panama City, Florida, May. FUSE Weidlinger Associates, Inc. The FUSE code is a newly developed hydrodynamics shock and structural dynamics code based on a Lagrangian treatment of material motion and deformation. This approach allows the numerical analysis to proceed without the nonphysical numerical diffusion of dissimilar materials (such as high-explosive gas and solid structures) across their mutual interfaces. The procedure involves a new computational technique to avoid the adverse effects of large distortion on conventional Lagrangian codes. The code is currently being generalized to three dimensions and to include structural (shell) elements. It can be run on supercomputers, workstations, or even personal computers. FUSE is capable of dealing with arbitrary deformations and motions of materials of any properly posed constitutive type. It can accurately represent the shock-wave propagation and gas expansion resulting from explosions, as well as their effects (in terms of structural loading). The code, which is under continuing development at Weidlinger Associates, is used to analyze multidimensional and multimaterial physical problems. One-dimensional spherical and two-dimensional cylindrical geometries are currently available, with the three-dimensional version nearing completion. The code is based on a new algorithm which allows each element to be cycled at its own time step. This permits the Lagrangian procedure to accommodate any large distortions which may arise. (A small displacement, two-dimensional version of the code is also available.) Aside from the time-step cycling, FUSE utilizes several other novel computational techniques. A new procedure for handling shocks replaces the artificial viscosity procedure commonly used in hydrodynamic codes. This procedure not only properly computes shocks, but works just as well for acoustic waves, avoiding the usual numerical dispersion and dissipation associated with all of the standard shock algorithms. A new approach is also utilized to follow the kinematics of finite deformation in a physically and numerically objective way for solid materials. Another important aspect of the new code is the nature of its discretization scheme. This scheme differs from the standard finite-element approach in that the codes carry only acceleration/velocity information, but do not carry position or
OCR for page 94
Page 94 deformation data. These instead are carried at the element centers only. Further, the laws of conservation of mass, momentum, and energy are exactly satisfied (to the numerical accuracy of the computer) for the discretized system. FUSE has several mechanical and thermodynamic constitutive models available for representing solid as well as fluid behavior. Solids can be represented by CAP (elastic-non-ideally-plastic) models, as elastic-ideally-plastic, or viscoplastic materials. Simplified analytic equations of state are available for air and water, and the Jones-Wilkins-Lee equation of state is available for modeling high-explosive reaction products. Various failure models are available, including one specifically designed to represent the cavitation of water. FUSE documentation is sparse as the code is new and still relatively young in its development. Its use in problems involving water shock is documented but a users guide is not yet available. The existing versions of the code require extensive training, but future versions are expected to be much more user-friendly. FUSE uses a graphics package which permits snapshots to be displayed on X-windows-based workstations, and all quantities can be displayed graphically as functions of time. Color and black-and-white PostScript files are available for hardcopy output. The FUSE code allows the numerical analysis of very general, nonlinear dynamic problems involving arbitrary materials and geometry changes. It is well suited for defining explosive loadings on structures and for determining the resulting effects. Reference: Sandler, I.S., and D. Rubin. 1990. FUSE Calculations of Far-Field Water Shock Including Surface and Bottom Effects. New York: Weidlinger Associates. Distribution limited to SAIC. HULL Orlando Technology Inc. The HULL code is a comprehensive system of finite-difference algorithms which solve the nonlinear partial differential equations descriptive of an elastic/ plastic/hydrodynamic continuous medium. The code is modularized to treat two-and three-spatial dimensions in either Euler, Lagrange, or linked reference systems. The numerical techniques are fully second order in space and time for both modules. HULL uses a material library for definition of material properties. This methodology allows the user to add experimental or theoretical descriptions for a material to the library along with the equation-of-state type to be employed. Elastic-plastic behavior is modeled with a Von Mises flow rule. Isotropic and orthotropic materials can be modeled. Phase changes account for the energy of sublimation and fusion. The Mie Grunieson equation of state is most widely used for metals and composites. The code can treat failure through criteria for ultimate
OCR for page 95
Page 95 stress, ultimate strain, or a triaxial stress versus stain failure surface. HULL has been used to investigate the effects of conventional ordnance and other high-rate deformation phenomena for over a decade. Reference: Gunger, M. 1992. Progress on Tasks Under the Sympathetic Detonation Program. WL/MN-TR-91-85, Shalimar, Florida: Orlando Technology, Inc. MAZe (multiphase adaptive zoning) TRT Corporation The MAZe computational fluid and solid dynamics code was originally developed to simulate problems of interest to the Defense Nuclear Agency (DNA), mainly for weapon-effects scenarios such as nuclear and conventional explosions and dust clouds. The code evolved from the previous DNA-sponsored codes DICE and CRALE. More recent defense-related applications have included incendiary weapons, electrothermal-chemical guns, simulations of collateral effects from explosions in facilities containing nuclear, chemical, or biological agents, and hypersonic flow over missiles. The code has also been broadened to model such nondefense applications as turbo machinery, diesel engines, and asteroid and comet planetary impacts. MAZe has been validated against laboratory and field-test experiments for most of these applications. The code has modern numerical features such as adaptive zoning and total variation diminishing differencing, and also has models for a wide variety of physical processes, such as multiple interacting phases (gas/solid/liquid) and multiple reacting chemical species. The code also models solid materials and fluid-solid interactions, either directly in the code or by coupling to a finite-element structures code. Explosion-structure interactions with severe structural damage and cratering may therefore be simulated. High explosives that have been modeled include Tritonal, C-4, ANFO, LX-10, and others. References: Schlamp, R.J., P.J. Hassig, C.T. Nguyen, D.W. Hatfield, P.A. Hookham, and M. Rosenblatt. 1995. MAZe User's Manual. Los Angeles, California: TRT Corporation. SHARC Applied Research Associates, Inc. The second-order hydrodynamic advanced research code (SHARC) is a library of routines that is used to solve the equations of motion for inviscid, nonconducting, compressible fluid flow. The method of integration is time marching, explicit and fully second-order accurate in space and time. The solution is fully conservative and zone-centered in a rectangular Eulerian mesh in two or three
OCR for page 96
Page 96 dimensions. Multiple materials and two-phase flow are readily handled. Many physical models and equations of state are included in the library. A preprocessing code, developed by Leon Wittwer at Defense Nuclear Agency, is used to construct a FORTRAN-compilable code by selecting subroutines and lines of code from the library. The selections are based on input conditions and parameters defined by the user as part of the problem definition. The code, thus constructed, is designed specifically for the problem of interest, on the machine of interest, and is extremely efficient of computer resources. Some of the physical models available include high-explosive burn in two or three dimensions, a two-equation turbulence model for compressible nonsteady flow, a nonequilibrium chemistry package, and a capability for including nonresponding structures within the flow. Points within the grid may be designated, at the start time, which monitor the hydrodynamic parameters as a function of time. Several models are available for calculating the effects of dust or particulate matter, and an extension of these models can be used to predict the influence and effects of fragments from conventional munition. Automatic rezones are included which can expand the overall grid or follow shocks or other regions of interest. SHARC includes a general problem-initiation program. Initial conditions can be established from a wide variety of other codes or from previous SHARC calculations. A selection of ambient atmospheric conditions is available. Boundary conditions may be transmissive, reflective, or specified by feed-in conditions as a function of time. A full set of postprocessing and graphics is included in the library. Selections of histograms, contours, color graphics, and vectors are available for all hydrodynamic parameters. Plots can be made of parameters as a function of position at a given time or as a function of time at a given position. Plots are also available as a function of time for specified points which move with the flow. A brief description of the solution method and results of a number of sample problems can be found in the reference cited below. Reference: Hikida, S., R. Bell, and C. Needham. 1988. The SHARC Codes: Documentation and Sample Problems. SSS-R-89-9878, September. Albuquerque, New Mexico: S-Cubed division of Maxwell Laboratories. Distribution limited.
Representative terms from entire chapter: