Characterising bonded joints with a thick and flexible adhesive layer. Part 2: Modelling and prediction of structural joint responses

Abstract

Adhesively bonded structural joints have increasingly found applications in automotive primary structures, joining dissimilar lighter-weight materials. Low-modulus rubbery adhesives are attracting rising interest as an alternative to conventional rigid structural adhesives due to benefits such as the excellent impact resistance they provide. In this pair of papers, the mechanical behaviour of a rubbery adhesive and the bonded joints to be used in a lightweight automobile structure have been investigated, both experimentally and numerically. In this (part 2) paper, progressive damage FE modelling using cohesive elements is presented to predict the structural response of peel and lap shear specimens that were representative of the vehicle joints. The cohesive parameters that matched the load–displacement curves of the fracture testing presented in part 1 were determined and used, without modification in subsequent modelling of the representative joints. The numerical predictions of these joints correlated well with the measured experimental load–displacement and damage growth data. Based on the results, it has been demonstrated that the modelling approach presented is applicable to bonded joints with a highly compliant, thick adhesive layer.