Method of fracture toughness evaluation of adhesive joints

This paper presents the development of a testing method for adhesive joints under Mode 1 fracture. The proposed testpiece consists of two slender beans with a ‘blister’ at the centre of each, which are bonded together and loaded in compression. The effect of buckling and the stability of crack propagation is analysed and found to be in satisfactory agreement with experimental observations. Equations for the evaluation of the fracture toughness based on the energy criteria are derived for the proposed test configuration. The results obtained using the method are checked with those from the DCB specimen and found to be satisfactory.