<![CDATA[Delamination is a critical interlaminar failure mode in laminated composites, particularly under mixed-mode loading where opening and shear mechanisms interact during crack propagation. This study investigates the effect of loading configuration and displacement ratio on mixed-mode delamination behavior using a finite element model incorporating finite-thickness cohesive zone elements. Three loading configurations, namely single-leg bending (SLB), modified single-leg bending (MSLB), and mixed-mode bending (MMB), were investigated. For MSLB and MMB, five additional-to-primary displacement ratios ranging from 0.5 to 2.5 were applied. Delamination behavior was evaluated in terms of load-displacement response, delamination area, and mode-mixity evolution. The results showed that increasing the displacement ratio increased the delamination area in both MSLB and MMB configurations. The MSLB delamination area increased from 15.04 to 30.71 mm², whereas the MMB area increased from 24.53 to 50.80 mm². MSLB exhibited a transition from predominantly shear-controlled toward greater opening contribution as the displacement ratio increased, while MMB remained predominantly shear-controlled during most of the propagation process. Among configurations with comparable maximum loads, MSLB 1.5 produced a smaller delamination area of 21.37 mm² than SLB of 23.90 mm², and MMB 1 of 28.96 mm². These findings demonstrate that mixed-mode delamination is governed by the interaction between loading configuration, displacement ratio, and evolving mode-mixity. The finite-thickness cohesive-zone approach provides an effective numerical framework for evaluating delamination propagation under different mixed-mode loading conditions.]]>
Copyrights © 2025
