Analysis of Crack Propagation in Composite Materials Using Mixed Finite Elements

Abstract This study investigates the application of fracture mechanics to analyze cracked structures, particularly focusing on cracks along interfaces in multilayer materials. Assuming perfectly plastic elastic behavior, small displacements, and plane structures, the research employs a new mixed finite element, RMQ-7, derived from Reissner’s variational principle. The RMQ-7 element, designed to model both the free edge effect along the crack and continuity in the rest of the material, is used in conjunction with the virtual crack extension method to evaluate the energy release rate and the size of the plastic zone around the crack tip. Numerical modelling is conducted on various configurations, including plates with central and inclined cracks under different loading conditions. The study concludes that the RMQ-7 mixed finite element is an effective and precise tool for analyzing interface cracks in multilayer materials, providing valuable insights into the mechanical behavior of such structures under stress.