Progressive failure analysis of the fiber metal laminates based on chopped carbon fiber strands

In this study, we propose a new fiber metal laminate based on unidirectionally arrayed chopped strand (UACS) reinforced aluminum sheets, referred to as UACS/Al laminate. UACS is made by introducing slits into unidirectional carbon fiber-reinforced plastic (CFRP) prepreg. Due to the presence of discontinuous fibers, the microstructure of the UACS/Al laminate is much more complicated than the conventional fiber metal laminate, which also results in a failure progression that is more complicated. Tensile failure of the UACS/Al laminate might occur as combination of intra-laminar damage at the slits, inter-laminar damage at the interfaces, in-ply damage of the CFRP, and plastic deformation of the aluminum plies. Fabrication and tensile tests of UACS/Al laminate specimens were performed. A two-dimensional finite element model was developed with intra-laminar cohesive elements inserted into the slits of the UACS plies and with inter-laminar cohesive elements inserted into the interfaces between all laminas in the modelled UACS/Al laminates. A numerical study is conducted to investigate the influence of the shape of the cohesive laws on the FEA predictions. The combined experimental and numerical studies provide a detailed understanding of the failure progression of UACS/Al laminates under tensile load.