Material behaviour of Composites by three dimensional load conditions

The material and failure behaviour of composites by static load conditions is complex. The material properties are dependent of local damages. Polished micrograph sections demonstrate an early damage initiation, without drop-offs in the load displacement curve. Additionally, for load introduction sections the behaviour between associated plies is characteristic. A new test setup is developed to analyse these interlaminar material properties. Single and combined interlaminar material load conditions are experimentally analysed by this test device within a cross ply laminate. The determination of interlaminar material properties provides the definition of a new damage model. Based on an established damage hypothesis the damage phenomena within the elementary ply as well as adjacent plies are included in one model approach. The behaviour of relative thick laminates is analysable with three dimensional finite elements. Therefore no discretisation is required for the interface between adjacent plies, which reduced the computational effort.