Comparative study of failure models for prediction of mixed-mode failure characteristics in composite adhesively bonded joint with brittle/Quai-brittle adhesive using finite element analysis

Abstract In the paper, detailed numerical comparisons are considered for the mixed-mode failure characteristics of different composite adhesively bonded joints with brittle/quasi-brittle adhesive using following failure models: cohesive zone model (CZM), virtual crack closure technology (VCCT), mixed-mode continuum damage model (MCDM) and finite fracture mechanics (FFM). Detailed numerical comparisons contain the stress and energy, and crack propagation near a crack tip with mode mixity when the adhesively bonded joint made of unidirectional carbon fiber reinforced composite adherend (SEAL® Texipreg HS 160 RM) and brittle adhesive AV138 is subjected to the mixed-mode load. The traction-separation law assumes the bilinear cohesive law to model the brittle/quasi-brittle adhesive and the quadratic stress criterion and B-K energy failure criterion are used. Also, an alternative numerical formulation of FFM is considered for the prediction of failure characteristics in the composite single lap joint. Moreover, the sensitivity analysis is performed to account the effect of parameters in the coupled FFM criteria, using four parameters. Next, predicted failure loads are compared with results in previous references for various types of adhesively bonded joints such as double lap joint (DLJ), scarf joint and single-L joint. Finally, the effect of constraint due to adherend bending is analyzed with varying the adhesive thickness, leading to more accurate prediction of failure load.