USE OF J-INTEGRAL AS FRACTURE PARAMETER IN SIMPLIFIED ANALYSIS OF BONDED JOINTS

The simplified analytical approaches based on beam or plates theories are commonly used to solve the stress field in bonded laminates. Howev er, to be correctly applied, these methods require an appropriate frac ture criterion. In this paper, the use of J-integral as a Fracture par ameter in these simplified analytical approaches is discussed. After e xamining its path independence, the J-integral is calculated along two particular paths showing first that this integral is equal to the pro duct of the strain energy at the end of the joint (i.e. at the debond tip) by its thickness. This relationship reveals the partitioning of t he opening mode I and the shearing mode II. Secondly, the general expr ession of J as a function of the loading conditions is derived. It is shown that this parameter can be related to the strain energy release rate in the cases of small scale yielding conditions and for usual fra cture mechanics specimens.