MULTI FRACTURE/DELAMINATION ANALYSIS OF COMPOSITES SUBJECTED TO IMPACT LOADINGS

A combined finite/ discrete element method is presented for modelling of composite specimens subjected to dynamic/impact loadings. The main task is set on developing an algorithm for simulation of potential bonding and debonding/delamination phenomena during impact or general dynamic loading conditions. In addition, full fracture analysis can also be performed. The proposed approach adopts a general node to face nonlinear frictional contact algorithm to enforce bonding/debonding constraints between composite plies. The method is also capable of analysing progressive fracture and fragmentation behaviour as well as potential post cracking interactions caused by the newly created crack sides and segments. A local remeshing technique is adopted every time a new crack is formed, while an overall remeshing is performed anytime a certain criterion of error estimation is violated. The special local remeshing technique is designed to model geometrically an individual crack by splitting the element, separating the failed node, creating new nodes and dividing the neighbouring elements to preserve the compatibility conditions. The same procedure is capable of modelling application of fibre reinforced polymer (FRP) layers to other engineering structures in order to improve their flexible behaviour in static and dynamic loading conditions.