DAVID J. BENSON

Professor of Applied Mechanics

Point of Contact Department of Applied Mechanics and Engineering Sciences University of California, San Diego 9500 Gilman Drive La Jolla, CA 92093-0411 E-Mail: dbenson@ucsd.edu Office: 283 EBUII Phone: (858) 534-5928 FAX: (858) 534-7078

Current Research

Figure 1: Experimentally acquired microstructures are directly imported from photomicrographs into an Eulerian finite element program developed by Prof. D. Benson. Figure a is the original metal matrix composite microstructure, b is the initial finite element model, c is a representative section of the material after compression, and d is the predicted failure mode (red indicated material failure). The computer calculation reproduces the characteristic debonding failure that is found in the experiment. The experimental results were supplied by Prof. K. Vecchio.

Figure 2: The formation of chips during machining is simulated with a multi-material Eulerian finite element program develop[ed by Prof. D. Benson at UCSD. The workpiece is 4340 steel modeled with the Johnson-Cook plasticity model. As the tool cuts the material, the chips form by the successive formation of shearbands. The regions of greatest localization are red. To help visualize the material deformation, contour lines of the initial X and Y coordinates of the material are plotted.

Figure 3: The shock compaction of a nickel powder is simulated on the micromechanical level with an Eulerian finite element program developed by Prof. D. Benson at UCSD. As shown, the melting is localized and the temperature distribution is highly heterogeneous.

Figure 4: Shock compression is used to synthesize and study the properties of novel materials. The interactions between the particles are difficult to study experimentally and calculations are required to study them in detail. The morphology of the particles has a substantial effect on how they interact. To ensure that the calculation is accurate, the powder particle shapes are directly imported into a multi-material Eulerian finite element program developed by D. Benson at UCSD.

Education

Doctor of Philosophy, 1983
Mechanical Engineering,
University of Michigan, Ann Arbor, Michigan.

Master of Science, 1980
Mechanical Engineering,
University of Michigan, Ann Arbor, Michigan.

Bachelor of Science, 1978
Mechanical Engineering,
University of Michigan, Ann Arbor, Michigan.

Positions Since Ph.D.

6/91-present: Professor, University of California, San Diego Research on computational methods for nonlinear, large deformation problems in solid mechanics. Recent research includes analysis of ductile fracture using an Eulerian finite element formulation, fundamental mechanisms in shock compaction, arbitrary Lagrangian Eulerian (ALE) and Eulerian finite element formulations, and methods for monotonic element-centered momentum advection.

5/87-6/91: Assistant Professor, University of California, San Diego Research on computational methods for nonlinear, large deformation problems in solid mechanics.

2/84-4/87: Research Engineer, Lawrence Livermore National Laboratory Nonlinear finite element research, primarily for explicit, nonlinear finite element programs such as DYNA3D. Research topics include multi-tasking, combined rigid body and finite element formulations, single surface contact for the post buckling analysis of shell structures and ALE formulations.

10/78-1/84: Principal Analyst, Mechanical Dynamics, Incorporated Consulting and software development. Principal author of ADAMS2D (Automatic Dynamic Analysis of Mechanical Systems-2D), the DRAM postprocessor, the DMP (Data Modification Program), and development work on ADAMS (3D) and DRAM (Dynamic Response of Articulated Mechanisms).

Professional Societies

Member of American Society of Mechanical Engineers (ASME).
Member of the ASME Committee on Computing in Applied Mechanics.
Member U. S. Association of Computational Mechanics.
Member Tau Beta Pi.

Selected Publications

1. Benson, D. J., "A New Two-Dimensional Flux-Limited Shock Viscosity for Impact Calculations," Computer Methods in Applied Mechanics and Engineering, Vol. 93, 1991, pp. 39-95.
2. Benson, D. J., "Momentum Advection on a Staggered Mesh," Journal of Computational Physics, Vol. 100, No. 1, May 1992, pp. 143-162.
3. Benson, D. J., "Computational Methods in Lagrangian and Eulerian Hydrocodes," Computer Methods in Applied Mechanics and Engineering, Vol. 99, 1992, pp. 235-394.
4. Benson, D. J., "An Analysis of Void Distribution Effects on the Dynamic Growth and Coalescence of Voids in Ductile Metals," Journal of Mechanics and Physics of Solids,Vol. 41, No. 8, 1993, pp. 1285-1308.
5. Benson, D. J., "An Analysis by Direct Numerical Simulation of the Effects of Particle Morphology on the Shock Compaction of Copper Powder," Modelling and Simulations in Materials Science and Engineering, 1994, Vol. 2, pp.535-550.
6. Benson, D. J., "Dynamic Compaction of Copper Powder: Computation and Experiment," Applied Physics Letters, July 25, 1994, Vol. 65, No. 4, pp. 418-420.