Energy Release Rates for an Edge Delamination of a Laminated Beam Subjected to Thermal Gradient

Energy release rates for an edge delamination of a laminated beam subjected to through-thickness temperature gradient are analyzed on the basis of the classical beam theory. The decomposition of the energy release rate into mode I and mode II components is made by combining the analyses of the energy release rates by Toya (1992) and the two-dimensional elasticity solutions for a split-beam element by Suo and Hutchinson (1990). The energy release rate is a quadratic function of the temperatures of the top and bottom surfaces of the beam. The transition of the type of crack growth between pure mode II and mixed mode type occurs at the temperature difference corresponding to the minimum energy release rate. Numerical analyses based on finite-element method are also carried out, which show that the theory agrees well with numerical results when temperature jump across the delaminated surfaces is relatively small as compared with the temperature difference between the top and bottom surfaces of the layered beam.