FRACTURE OF ALUMINA TUBES UNDER COMBINED TENSION TORSION

Abstract

A fracture criterion for Al2O3 tubes is investigated for various loading paths under combined tension and torsion. Experimental data are compared with the Weibull statistical fracture theory. As the stress state approaches a shear dominant state, a tensile principal stress at fracture from the Weibull theory underestimates strengthening effects. By including the effect of the minimum principal stress in the tensile principal stress criterion, an empirical fracture criterion is proposed. Agreement between the proposed criterion and experimental data for Al2O3 tubes under combined tension/torsion and balanced biaxial tension is very good.