Failure criterion with given survivability for ceramic notched elements under combined tension/torsion

In the present study, a generally applied failure criterion is developed for the elements of brittle materials under combined tension/torsion based on the normal stress fracture criterion. First, the applicability of the failure criterion mentioned above is objectively checked by test results of the fracture stress of Al2O3 ceramic under combined tension/torsion given in the available literature. Furthermore, the failure criterion is modified to take account on the greater effect of the shear stress component on the fracture of Al2O3 ceramic under combined tension/torsion, and rechecked by test results of the fracture stress of Al2O3 smooth tubes and round rods under combined tension/torsion. Tests also were carried out to determine the fracture stress of Al2O3 notched tubes under combined tension/torsion, which are used to test the general applicability of the failure criterion. Finally, the failure criteria with given survivability for Al2O3 smooth- and notched elements under combined tension/torsion are predicted from the probability distribution parameters of the tensile fracture strength and the shear fracture strength of ceramics and checked by test results.