Nonlinear CZM-based predictive analysis of damage in single-lap composite joints: An exploration of the FGM concept in Fiber–Matrix coupling

Abstract

This study introduces an innovative numerical approach, validated through experiments, to incorporate functional graded materials (FGMs) volume fractions into mixing laws for fiber–matrix unidirectional composites. Nonlinear techniques address adhesive ductility, with the cohesive zone modelling (CZM) model integrated into finite element analysis using the ABAQUS code. The CZM model encompasses shear and detachment modes, characterized by adhesive stress increase in a trapezoidal shape. Proposed strategies introduce layer-specific fiber presence; concepts like C-1 exhibit denser fibers toward the middle, while C-2 and C-3 position them nearer to the plate edge. Stiffness from attached plates significantly governs overall responses, particularly under mixed loading conditions. The results have shown that the proposed grading concept C-2 provides an over-resistance capacity compared to other concepts. Additionally, using a special mesh in the composite grading, the results indicate that the adhesive formulation used in this analysis and the approach followed are primarily based on experimental results, demonstrating good agreement with the numerical model employed.