An adaptive thick shell element for crashworthiness assessment of laminated composites
The automotive industry is strongly dependent on efficient numerical tools in order to assess the crashworthiness of laminated composites. Unfortunately, to achieve predictive assessments of fracture in laminated composites one must resort to computationally costly, high-fidelity layered models, which in practice makes full vehicle crash simulations very difficult (or even impossible). One solution to this is to use an adaptive modelling technique where an initially coarse model is automatically refined, when and where needed, during the analysis.
In this context, we have developed an LS-DYNA® user element which can be adaptively refined through the thickness to allow for both so-called weak discontinuities (discontinuities in strain at material interfaces) and strong discontinuities (discontinuities in displacements, i.e. delamination cracks). Furthermore, we have proposed a remedy to the numerical instabilities which arise from using adaptive refinement in a dynamic explicit solver. This adaptive element proves capable of reproducing the result of high-fidelity models, although at a lower computational cost.