Topics in Computational Modeling of Shock and Wave Propagation

Report No. ARL-SR-145
Authors: George A. Gazonas
Date/Pages: September 2006; 30 pages
Abstract: This report addresses several practical problems related to computational modeling of shock and wave propagation in cellular, viscoelastic, microcracked, and fragmented media. ?Impulsive Loading of Cellular Media in Sandwich Construction? derives an analytical model for a cellular medium subjected to blast and examines the influence of the relative distribution of mass among the cellular core and the front and back faces of the sandwich structure. ?Transient Stress Optimization of Elastic and Viscoelastic Composite Strips? examines wave propagation in elastic and viscoelastic layered media, with the goal of minimizing stress amplitude in the layers. Solutions to initial boundary value problems are obtained via Laplace transform methods using a modified Dubner-Abate-Crump algorithm. ?Numerical Modeling of Wave Propagation in Anisotropically Microcracked Media? utilizes a generalized self-consistent method to evaluate the effective moduli in microcracked media. Slowness diagrams illustrate key features of the anisotropic nature of the quasi-longitudinal and shear wave speeds in microcracked media subjected to either a far-field compressive or tensile load. Finally, ?Numerical Convergence of the Cohesive Element Approach in Dynamic Fragmentation Simulations? solves a long-standing problem related to energy convergence in numerical simulations of fragmentation in brittle materials. It is shown that a random finite-element mesh spacing leads to much faster and smoother convergence of the dissipated cohesive energy than uniform meshes.
Distribution: Approved for public release
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Last Update / Reviewed: September 1, 2006