Study on bending properties and damage mechanism of carbon fiber reinforced aluminum laminates

Carbon fiber reinforced aluminum laminates (CARALL) are often subjected to bending loads in actual working conditions, resulting in some imperceptible intra-layer or inter-layer damages, such as matrix cracking, fiber fracture and inter-layer delamination, which degrade the mechanical properties of the structure. In this paper, the bending performance and damage mechanism of CARALL are tested and simulated by finite element simulation. Firstly, the mechanical properties are analyzed by three-point bending test, and the fracture morphology of the specimen after failure is photographed by scanning electron microscope, and the failure damage state from the microscopic perspective is analyzed. Secondly, the VUMAT subroutine with built-in three-dimensional Hashin criterion is introduced into ababqus. By comparing the finite element simulation and experimental results, the rationality and accuracy of using VUMAT subroutine to predict the failure behavior of Al-CFRP-Al laminates are verified. The results show that during the bending failure process, the aluminum alloy layer suffered local damage, and the carbon fiber layer suffered a large area of damage. The layer near the indenter was subjected to large stress concentration during bending, resulting in intensified interlayer interaction and serious damage. The crack began to expand downward along the stress and gradually became smaller as it expanded. The research results provide basic data reference for the bending performance and damage mechanism of fiber metal laminates (FMLs), and have important engineering application value for the optimization design of related structures.