On controlling interfacial heterogeneity to trigger bridging in secondary bonded composite joints: An efficient strategy to introduce crack-arrest features

Abstract Secondary adhesive bonding of carbon fiber-reinforced polymer laminates is of great interest for the aerospace and automotive industries. However, joint reliability is still a major concern because of fabrication-induced or service-related cracks that are difficult to monitor and can lead to catastrophic failure. In this work, we propose a patterning strategy where the careful design of spatially-varying interface properties enables the formation of an adhesive ligament that acts as a crack-arrest feature. Bi-dimensional finite element models of adhesively bonded double cantilever beams were employed to investigate the role of the main parameters of the pattern ( i . e . , geometrical parameters and interfacial properties) under mode I loading. The results show that an adhesive ligament can either bridge the separating arms, largely enhancing the dissipated energy, or fail, thereby limiting the attainment of a R-curve-like response. The precise scenario is heavily dependent on the contrast in interfacial properties rather than the geometrical details of the pattern.