Efficient sublaminate-scale impact damage modelling with higher-order elements in explicit integration

Abstract

Damage modelling in composite structures with ply-level discretisation is computationally expensive for analysing large structures. In such cases homogenisation to the sublaminate length-scale is essential. However finite element discretisation requirements in bending problems imposed by conventional explicit-solver single-integration point solid elements results in a computationally expensive mesh, eroding the advantages of the larger length-scale. To benefit from using the sublaminate-scale and model the bending and torsional strains accurately a higher-order continuum solid element formulation is used in this work. This improved intra-element continuity enables evaluation of intralaminar strains and the corresponding damage at the sublaminate-scale accurately. Ply-level distributions are imposed through the thickness of these sublaminates to be able to use any ply-level damage initiation and evolution criteria available in the literature. Interlaminar damage calculation is performed using adaptively initiated higher-order cohesive segments thus simplifying pre-processing effort and enabling coarser in-plane mesh sizes without being limited by the mesh size requirements of cohesive zone modelling. This sublaminate-scale damage modelling strategy is verified using impact modelling examples performed with explicit time integration. Computational benefits are compared against conventional linear elements.