Failure modes and mechanical behavior of bioinspired CFRP mortise-tenon structures under tensile loading

The expanding use of carbon fiber-reinforced polymer (CFRP), valued for its high specific strength and modulus, in joining dissimilar materials has heightened the need to understand the mechanical behavior of these connections. Inspired by the microstructural morphology of beetle elytra, this study proposes a Bioinspired CFRP Mortise-Tenon Structure (BCMTS) and establishes a two-dimensional continuous shell model using the Abaqus platform. Numerical simulations reveal that the load-bearing capacity of BCMTS is nonlinearly influenced by key geometric parameters and layup configuration. An optimal geometric configuration maximizing structural strength was identified. Furthermore, a quadratic model for predicting the tensile strength of BCMTS was developed using Kriging interpolation and the Levenberg-Marquardt optimization algorithm. The bioinspired layup design achieved an ultimate tensile strength of 1807 MPa and a corresponding peak load of 22.01 kN—representing enhancements of 108% and 136%, respectively, over conventional [0/90] 5 layup. Furthermore, the study maps failure modes and stress concentrations across different geometries and layups, offering a foundation for targeted structural optimization.