Adaptive Mesh Segmentation for Modelling Dynamic Delamination Initiation and Propagation in Thick Composite Laminates

Composites subjected to out-of-plane stresses due to impact loading can suffer from multiple delaminations, but modelling these in large scale structures is a challenging problem. To address this, a methodology is proposed for modelling dynamic delamination initiation and propagation in composites. It adaptively segments the mesh with additional nodes which model the discontinuities in the displacement field caused by delamination. Besides, it also introduces cohesive segments between the newly created nodes so that delamination propagation is controlled by an energy criterion. These adaptations are performed ‘on-the-fly’ in a dynamic explicit Finite Element solution without the need for user intervention, and the mesh segmentation technique does not reduce the time increment size for solution stability. A technique to initialise cohesive tractions with minimal disturbances to the surrounding stress field is also presented. This methodology is described here in detail and demonstrated in the commercial finite element software LS-Dyna. Finally, it is validated against experimental data from the existing literature.