Effect of hygrothermal aging on the quasi-static behaviour of CFRP joints varying the overlap length

Adhesively bonded joints with composite substrates are crucial for the manufacture of lightweight structural components for the automotive industry. However, the safety of the vehicles must still be ensured after hygrothermal aging of both composite substrates and adhesive, as adverse conditions such as moisture and temperature will be a constant during a vehicle lifecycle. This work studies the influence of hygrothermal aging and temperature on the quasi-static behaviour of adhesive joints made with unidirectional composite substrates and a crash resistant adhesive using different overlap lengths. A complementary numerical simulation was performed to model both the water uptake processes and the failure process of moisture affected materials. Both the simulation and the experimental data showed increased susceptibility to delamination failure induced by water absorption in the composite and changes in the adhesive properties.