Abstract
Fracture strength of silicon nitride was studied under biaxial stress states. Multiaxial fracture distribution functions by several fracture criteria were employed to analyze tension/torsion, compression/torsion test. The most appropriate criterion was Shetty's empirical equation (parameter c=1.4) and the modefied G criterion (parameter β=0.9). The fracture strength of a disk for a spin test was estimated by the equivalent normal stress of Shetty's empirical equation and the modified G criterion. Good agreement between the experimental data and the estimated values were obtained.
