Strategy For Toughening Interfaces In Adhesively Bonded Composite Joints

Abstract

Objective: Surface patterning strategy was proposed to facilitate the formation of adhesive ligaments using pulsed CO2laser irradiation, in order to enhance fracture toughness and arrest the crack propagation within adhesively bonded composite joints.

Methods: Arrest regions (highlighted in green in the video), with higher interfacial strength but lower fracture toughness than the uniformly laser ablated (LA) baseline surface, are alternatively placed on the top and bottom CFRP/adhesive interface. Mode I fracture toughness was assessed through the double cantilever beam (DCB) configuration.

Results: The proposed patterning strategy is promising to trigger adhesive ligaments and hold the separating arms, promoting a R-curve-like response of the bonded joint, where the energy release rate keeps increasing as the crack propagates. The proposed patterning strategy shed light to the design of reliable and safety adhesively bonded CFRP joints.