Fracture toughness and shear behavior of composite bonded joints based on a novel aerospace adhesive

In this paper, the mechanical performance of the newly developed LMB aerospace structural adhesive has been characterized experimentally. To this end, a comparison has been performed with the Epibond 1590 A/B adhesive on the basis of the effects of thermal aging, wet aging and adhesive thickness on the fracture toughness and shear behavior (static and fatigue) of bonded joints between CFRP laminates. Mode-I and -II fracture toughness was measured through tensile and 3-point bending tests on double-cantilever beam specimen, respectively, while the shear behavior of the joints was assessed through static and fatigue double-lap shear tests. A fractographic analysis of the fracture surfaces was performed in order to detect the failure mode of the bonded joint. The experimental results show a higher fracture toughness and improved fatigue behavior for the LMB adhesive.