Analytical solutions for non-uniformity of energy release rate of orthotropic double cantilever beam specimens with an adhesive layer

An improved plate model is proposed for the orthotropic double cantilever beam (DCB) specimens with an adhesive layer. The upper adherend of the DCB specimens was converted to a rectangular plate supported by a row of vertical springs and rotational springs at one end and subjected to a vertical uniform traction at the other end. The transverse deflection distributions of the present model along the width are determined using the Rayleigh-Ritz method. Then, combined with the virtual crack closure technique, the closed-form solutions for non-uniformity coefficient β and variation coefficient ν are obtained, from which the mode-I initiation fracture toughness can be determined precisely and conveniently.