Contact based delamination and fracture analysis of composites

A new approach based on the concepts of the discrete element method, is presented for impact resistance analysis of composites. The method is capable of analysing the progressive fracturing and fragmentation behaviour, as well as potential post-cracking interactions caused by the newly created crack sides and segments. The imminence of a material crack is monitored by an anisotropic Hoffman model. To avoid the mesh dependency of the results, a bilinear local softening model, based on modes I and 11, is also adopted in this study to account for release of energy and redistribution of forces that caused the formation of a crack. A special re-meshing method has been developed to geometrically model an individual crack by splitting the element, separating the failed node, creating new nodes and dividing the neighbouring elements to preserve the compatibility conditions. Numerical simulations have been performed to assess the performance of the proposed algorithm. The method has proved to be an efficient approach for impact analysis of composites undergoing progressive delamination and cracking. (C) 2002 Published by Elsevier Science Ltd.