Computational investigation of structured shocks in Al/SiC‐particulate metal‐matrix composites

Abstract

Purpose -Propagation of planar (i.e. one directional), longitudinal (i.e. uniaxial strain), steady (i.e. time-invariant) structured shock waves within metal matrix composites (MMCs) is studied computationally. Waves of this type are typically generated during blast-wave loading or ballistic impact and play a major role in the way blast/ballistic impact loads are introduced in, and applied to, a target structure. Hence, the knowledge of the basic physics of propagation of these waves is critical for designing structures with superior blast and impact protection capabilities. The purpose of this paper is to help advance the use of computational engineering analyses and simulations in the areas of design and application of the MMC protective structures. Design/methodology/approach -To derive the overall response of the composite material to shock type loading, a dynamic-mixture model is employed. Within this model, the known constitutive responses of the constituent materials are combined using the appropriate mixture rules. These mixture rules are of a dynamic character since they depend on the current state of the composite material and cannot be applied prior to the beginning of the analysis. Findings -The approach is applied to a prototypical MMC consisting of an aluminum matrix and SiC particulates. Both the intermediate-to-strong shock regime (in which the contribution of stress deviators to the stress field can be ignored) and the weak shock regime (in which stress deviators provide a significant contribution to the stress field) are investigated. Finally, the computational results are compared with their experimental counterparts available in the open literature in order to validate the computational procedure employed. Originality/value -Prediction of the spallation-type failure in a metal-matrix composite material (modeled using the dynamic-mixture model) has not been done previously. IntroductionOwing to their ability to simultaneously satisfy a variety of manufacturing/processing constraints and functional/performance requirements (via material property tailoring), advanced metal-matrix composites (MMCs) are increasingly being used in a variety of applications. Among these applications are the ones in automotive-engineering (e.g. crash-worthy structures), aerospace industry (e.g. space debris impact shields) and defense industry (e.g. light-weight, high-performance blast and ballistic protection systems) (Pandey et al., 2001). In these applications, full advantage is taken of the superior performance of MMCs under high loading-rate conditions. It is generally recognized that in order to further increase the performance of MMCs in the high loading-rate applications, improved knowledge of the basic physics related to shock-wave generation and propagation (addressed in the present work) and the associated micro-structure evolution and material deformation/degradation processes (to be addressed in our future work) is required.It is generally recognized that any analysis of the shock-wave generation and propa...

The effect of plain-weaving on the mechanical properties of warp and weft p-phenylene terephthalamide (PPTA) fibers/yarns

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“…The model was previously developed in Refs. [28][29][30] and upgraded using the coarsegrained molecular-level computational results presented in the previous section. The material constitutive model is of a linear orthotropic elastic character with progressively degradable longitudinal-tensile strength.…”

“…Following the procedure outlined in Refs. [28][29][30], the concomitant loss in the longitudinal Young's modulus as a function of the preludial compressive/tensile strain is next determined. The upgraded material model is then used in the present finite-element analysis.…”

“…Specifically, the results obtained are used to parameterize the progressive damage model developed in Ref. [28][29][30]. Toward that end, the results presented in Fig.…”

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