MULTI AXIAL TESTING OF ADHESIVELY BONDED JOINTS OF FIBER REINFORCED THERMOPLASTIC POLYMERS

In order to predict the mechanical behavior of adhesively bonded joints, it is necessary to develop robust numerical models. This robustness is only reached if an extensive experimental database with tensile, shear and complex combined peel and shear loads can be established. The purpose of this study is to present a multi axial device for testing adhesively bonded joints, using KS2-type specimens traditionally utilized for spot-weld characterization. The tests were conducted on a glass fiber reinforced thermoplastic polymer (PA6-6) composite adhesively bonded with a flexible polyurethane adhesive. This adhesive/substrate combination allows short process times and good performances. This experimental study investigates the effects of axial and shear load, loading speed, temperature and adhesive thickness on the mechanical properties of the joints which are compared in terms of stiffness and ultimate strength. Results show that the strength of the assemblies largely depends on the load orientation, the joint thickness, the loading speed and also the test temperature.