Effect of environment conditioning on mode II fracture behaviour of adhesively bonded joints

The effect of environmental conditions on the fracture behaviour of two types of adhesively bonded joints (wet-aged and non-aged) is experimentally studied under mode II loading. End Loaded Split tests were performed at various temperatures (55 degrees C, room temperature (RT) and 80 degrees C) on non-aged and aged specimens. The non-aged specimens were stored in a laboratory under controlled conditions at RT (23 degrees C/55 RH) while the wet-aged specimens were exposed to accelerated ageing in an environmental chamber at 70 degrees C/85% RH for four years. The data reduction was applied using an inverse method and two other direct methods. A good agreement between these methods is observed. The analysis of the obtained results shows that extremely long aging times considerably affect the fracture response of bonded joints under mode II (the fracture toughness of the wet-aged specimens degraded by more than 30%). Furthermore, testing at high or cryogenic temperatures has a significant effect on the fracture response. Indeed, testing at high temperatures was observed to increase the fracture toughness (this increase ranged from 8% to 80%) while cryogenic temperatures increased the brittleness of the adhesive which caused a substantial reduction (more than 25%) in the fracture toughness of the bonded joint.

Automated summary

The experimental study found that environmental conditions and temperature have a significant impact on the fracture behavior of adhesively bonded joints, with long aging times leading to decreased fracture toughness, high temperatures increasing toughness, and low temperatures increasing the brittleness of the adhesive.