Co-authors​ :

 Dharun VADUGAPPATTY SRINIVASAN (SWITZERLAND), Anastasios P. VASSILOPOULOS (SWITZERLAND) 

Epoxy materials find widespread application in the assembly of composite structures, subjected to complex mechanical and environmental loads. Owing to inherent defects, residual stresses, and in-service damage, cracks may develop and propagate under fatigue loads, posing a risk of catastrophic failure. Consequently, achieving fatigue damage tolerance is a highly sought-after material characteristic, and various strategies can be employed to enhance it. This study specifically investigates the fatigue crack arresting capability of thin (0.5 mm thickness) polyetherimide (PEI) and polyvinylidene fluoride (PVDF) thermoplastic interlayers in two epoxy materials (modified with short-glass fibers and core-shell rubber particles). Epoxy specimens with and without these interlayers are fabricated in a single edge notch bending (SENB) configuration and subjected to mode-I fatigue loading under increasing ΔK (stress intensity factor range) and constant ΔK conditions. This approach is employed to derive Paris curves and fatigue crack growth curves, respectively. The experimental results demonstrate a substantial improvement in fatigue damage tolerance for the interlayered specimens compared to the pristine epoxy materials. Fig 1. shows the mode-I fatigue experimental setup of the SENB specimen.