Double cantilever-beam test comparisons of Mode I fracture toughness of adherends bonded using DP8010 and DP8005 acrylic-based adhesives

The aim of this study is to not only measure the fracture toughness (GIC) of adherends bonded with a DP8010 acrylic-based adhesive using double cantilever beam (DCB) specimens under Mode I loading, but also to compare them with those bonded with DP8005. Aluminum alloy (5052-H34), glass fiber-reinforced polypropylene matrix composite (GF/PP), and carbon fiber-reinforced epoxy matrix composite (CF/EP) are used as adherends. Tensile tests of the adhesive bulk specimens are performed to measure the mechanical properties. R−curves measured from DP8010 and DP8005 are evaluated by relating them with failure modes observed from the fracture surfaces. Traction−normal separation relationships are considered to compare the fracture behaviors between DP8010 and DP8005. The experimental results show that the modulus of toughness (ur) for the adhesive bulk specimen of DP8010 exhibits similar values with that of DP8005. To maximize the values of GIC using acrylic-based adhesives, the following conditions need to be considered: ① strong bonding between adhesive and adherend, ② defect-free adherends, and ③ high ductile behavior of the adhesive bulk specimen.