SIMULATION OF OFF-AXIS FRACTURE OF THIN-PLY COMPOSITE LAMINATES USING PHASE FIELD
Anatoli MitrouDogwood B
Thin-ply laminates can offer significant advantages for aeronautical design, however, obtaining design allowables for such laminates requires efficient simulation tools. Previous simulation methods used for standard composites pose significant drawbacks when it comes to thin-ply composites, and therefore motivate the advent of new numerical techniques. The Phase Field method, a possible solution, is applied here, in an equivalent single layer approach, to simulate the fracture of multidirectional thin-ply laminates subjected to off-axis loading. The anisotropic nature of the fracture energy multidirectional laminates present is considered through an analytical formulation that feeds the inputs of the method. It is shown that accurate predictions can be obtained compared to experiments for off-axis open-hole tension (OHT) of a hard laminate. But this does not mean the same accuracy will be achieved regardless of the laminate type and lay-up. The issue is nicely illustrated considering a cross-ply laminate that presents the peculiarity of having the same translaminar fracture toughness in the two principal material axes. This creates some inaccuracies in the simulation due to the way the phase field model is formulated. A discussion on this issue and possible ways to circumvent it, under current development, will be presented.