Thermally Induced Stress Intensity in a Homogeneous Plate Containing a Finite Length Crack (Preprint)

摘要

The delamination of orthotropic laminates containing finite-length cracks and subject to thermal gradients is examined. The exact limiting case solutions for infinitesimal- and infinite-length cracks are known, and are equal to each other when the crack length is approximately equal to the plate thickness. However, in the transition region of crack length from about 1 to 5 times the plate thickness, both limit solutions overestimate the energy release by 20-100%. Hence, an analysis was developed to better predict the energy release rate for such finite-length cracks. The model is a modification of the infinite-crack analysis of Hutchinson and Lu (1995, ASME J. Eng. Mat. Tech., 117 (4) pp. 386-390) and provides a closed form expression for the elastic energy release rate in a plane-strain orthotropic flat plate that agrees well with numerical values for cracks of length approximately half of the plate thickness and larger. The analytic result is shown to agree well with finite element results over a wide range of crack lengths, depths and interface conductivity, both for isotropic and orthotropic materials.