Dynamic compressive strength properties of metal foams. Part II - 'Shock' theory and comparison with experimental data and numerical models.

One-dimensional 'steady-shock' models based on a rate-independent, rigid, perfectly-plastic, locking (r-p-p-l)l idealisation of the quasi-static stress-strain curves for aluminium. foams are proposed for two different impact scenarios to provide a first-order understanding of the dynamic compaction process. A thermo-mechanical approach is used in the formulation of their governing equations. Predictions by the models are compared with experimental data presented in the companion paper (Part 1) and with the results of finite-element simulations of two-dimensional Voronoi honeycombs.

A kinematic existence condition for continuing 'shock' propagation in aluminium foams is established using thermodynamics arguments and its predictions compare well with the experimental data. The thermodynamics highlight the incorrect application of the global energy balance approach to describe 'shock' propagation in cellular solids which appears in some current literature. (c) 2005 Elsevier Ltd. All rights reserved.