Progress in application of cohesive zone model in fracture simulation of aircraft metallic thin-walled structures

The Cohesive Zone Model (CZM) demonstrates significant value in the residual strength assessment of aircraft metallic thin-walled structures because of its straightforward parameter setting, high numerical stability, and ability to effectively simulate complex crack propagation behavior. This paper focuses on its Traction-Separation Law (TSL), systematically reviewing the geometric characteristics of typical TSL curves, initial stiffness, and the physical significance of key parameters. It also compares and analyses the applicability and differences among various TSL forms in simulating ductile fracture of metals. Building on this, this paper summarizes experimental measurement methods and numerical inversion techniques for cohesive parameters, and explores the influence of parameter selection on the accuracy of finite element simulations. Furthermore, regarding the numerical implementation of CZM, this paper categorizes and explains three modelling strategies: two-dimensional cohesive elements, shell elements, and three-dimensional cohesive elements, comparing their respective advantages and disadvantages. Through typical engineering case studies, the feasibility and applicability of CZM in simulating fracture in metallic thin-walled structures are validated. Looking ahead, to further enhance the application level of the cohesive zone model in metallic thin-walled structures, two critical scientific problems urgently need to be addressed: the quantitative relationship between cohesive parameters under different TSL shapes, and the correlation mechanism between TSL parameters and microscopic damage mechanisms.