2004 Volume 53 Issue 5 Pages 518-525
A laminated beam containing an interface crack subject to thermal gradient is analyzed on the basis of the classical beam theory. The axial forces are induced in the parts of the constituent beams above and below the interface crack. For the case where crack faces are open, a nonlinear equation for determining the in-plane forces is derived by modeling the cracked part as two lapped beams hinged at both ends, and by imposing the compatibility condition of the deformations of the two beams. Numerical solutions are obtained for some model beams. It is shown that the relative displacement at the center of the crack increases gradually with the increase in temperature gradient, However, at a critical temperature gradient, the relative displacement begins to increase very rapidly, i. e., local delamination buckling occurs. Energy release rate is small for temperature gradient below the critical value, but it takes a large value when the temperature gradient is increased beyond the critical value. The model where the two crack faces are contacting one another is also analyzed. In this case it is shown that the energy release rate is identically zero if the temperature gap between the crack faces is zero.
