Abstract
In this study, stress intensity factors were investigated and determined by the caustics and the photoelastic methods to clarify behaviors of crack tips under various biaxiality ratios. The polycarbonate plates with isotropy property and ones with anisotropy property were used as the specimens. As a result, it was confirmed that only "K_I" was generated regardless of biaxiality ratio, and material's property in case of the crack angle θ=0°. It was also confirmed that only K_I was generated in the isotropic polycarbonate plate with crack angle θ=45° under the biaxial load (1:1). In the case that the biaxiality ratio is more than 1:1 with crack angle θ=45°, both K_I and K_<II> are simultaneously generated in the isotropic specimens. Furthermore, the stress intensity factor, K_I, K_<II> values are influenced most by the extrusion direction in the case of the anisotropic specimens with the biaxiality load ratios exceeds 3.0.
