Paper number 1147

CRACK TIP STRESS FIELDS AND FRACTURE TOUGHNESS IN ADHESIVE JOINTS

Cheng Yan, Yiu-Wing Mai and Lin Ye

Centre of Advanced Materials Technology (CAMT), Department of Mechanical and Mechatronic Engineering J07, The University of Sydney, NSW 2006, Australia

Summary

To study the fracture behaviour of an adhesive joint, a thorough understanding of the crack tip stress field is essential. In this study, large deformation finite element analysis has been carried out for compact tension (CT) specimen with different bond thickness. Numerical results indicate a higher opening stress is observed in the joint with a smaller bond thickness (h) when loaded to the same applied J-integral value. Beyond the crack tip region, a self-similar stress field can be described by the normalized loading parameter J/h(o. The relationship between J and crack tip opening displacement is dependent on the bond thickness. For small bond thickness, toughness is linearly proportional to bond thickness caused by the high constraint. Beyond a critical bond thickness, the toughness decreases due to the rapid opening (blunting) of the crack tip with loading.

Keywords

adhesive joint, bond thickness, finite element analysis, constraint, fracture toughness.