Influences of Isotropic and Anisotropic Material Properties on Stress Intensity Factors of the Crack Tip under Biaxial Stress

Abstract

In order to clarify the effect of anisotropy on local deformation and the stress intensity factors in the vicinity of the crack tip under complicated stress states, biaxial loading tests were carried out on isotropic (Photoelastic sheet: PSM-1, Measurements Group, Inc) and anisotropic (LEXAN 9030, General Electric Company) polycarbonate materials. The biaxial dynamic loading device, which was developed by the authors, was fully utilized in the experiments. We carried out the experiments using isotropic and anisotropic specimens with a pre-processed 0°, 15°, 30°, 45°, 60°, 75° or 90° crack angle. We applied the equal biaxial stress, that is, the loads for both the Y- and X-axis as 0N : 0N-3920N : 3920N (1 : 1). We determined the stress intensity factors of specimens using both photoelasticity and caustics method. The results of the experiments were compared. As a result, when the materials with anisotropic property are used as machine or structural members, it is important to consider the extrusion direction of the material in their design.