Solution stability in the dynamic collapse of square aluminium columns

The collapse of empty square aluminium columns is re-examined using dynamic nonlinear elasto–plastic finite element analysis. Earlier work on this topic did not address the influence of FE model reduction on possible numerical anomalies resulting from the use of different processing platforms. Single- and double-sided impact conditions are also considered under both constant and varying initial impact speeds. Specifically, the objective of the study is to investigate the influence of numerical anomalies that are typically overlooked in the literature and the dramatic role they may play in dictating the dynamic mode of collapse. To that end the study investigates the influence of specific symmetric boundary and initial conditions on the resulting mode of collapse and determines the effect of the use of different platforms on the results. The work was carried out using LS-DYNA explicit finite element solver and considers generic geometries that are typically used in industrial applications. The results show clearly that the use of symmetry conditions in FE modelling must be used with proper care and that careful experimental work should be carried out to validate the finite element predictions.