An investigation of compliant contact force models applied for analysis of simultaneous, multi-zone impacts of particles

Abstract

Compliant contact force models were developed and mainly used to investigate simple impacts of two bodies. It is therefore unclear how they will perform in more complex cases, where simultaneous, multi-zone impact may occur. The aim of this study is to investigate phenomena that occur in such impacts and to study the effectiveness of preselected contact force models in their modelling. For this purpose, the study addressed collisions that occur in a collinear system of 3 to 6 particles made of steel, aluminium, and bronze. The results obtained for each force model were referenced to the FEM analysis. To compare the performance of the models, the Benchmark Velocity Indicator (BVI) is proposed. The study showed that during simultaneous, multi-zone impact direct switch from the restitution to compression phases may occur and subsequent collision along the same normal may take place. Such phenomena are not incorporated in current compliant contact force models; therefore, the study showed the need for their further improvement. The best models proposed by Kogut and Etsion (KE) and Jackson and Green (JG) achieved average errors equal to 3.89% and 4.15%, respectively. However, the same models in their worst cases reached error values of 38.66% and 33.77%. The article concludes with proposals for future improvements.