Behavior of pyramidal lattice core sandwich CFRP composites under biaxial compression loading

Pyramidal lattice core sandwich composites all made of CFRP is believed to have superior characteristics, as compared to the conventional composite and sandwich plates. Several articles addressed the behavior of this type of composite in the literature. However, its response under biaxial compression loading and its notch sensitivity was not covered within the current state-of-the art. In the current paper, numerical simulation tools were used to examen the failure mechanisms and the notch sensitivity of the pyramidal lattice core sandwich CFRP composite. The simulations adopted the LaRC failure criteria and property degradation rules. The model took into account the fiber tension and compression, the matrix tension and compression and the fiber matrix shear out failure mechanisms. The problem was solved with and without holes in order to examen the notch sensitivity. The model was validated against experimental results from the literature and showed good agreement. The results showed that these types of structures are less sensitive to notches, as compared to the traditional composites, which may guarantee the use of these structures in bolted joint and similar applications.