Macroscopic Brittle Fracture Criterion Under Multiaxial Stresses

Abstract

On the basis of traditional fracture criteria and numerous data on the fracture under multiaxial stresses, we propose a new macroscopic criterion for brittle fracture in the state where in biaxial or triaxial stresses, compressive stress predominates. We base our theory on the concept of fracture mechanics, especially of mode II fracture. Our criterion is expressed as follows, τc=τ0+ζ1(σ1+σ3)+ζ2σ2 where τ0 = (KIIc/KIc). at is the imaginary pure shearing strength of the material, ζ1 = (KIIc/KIc) (at/ac) – 1/2 and ζ2 are the coefficients corresponding to the restraint for crack propagation. The criterion may be applicable to mode II fracture which occurs in the state where compressive stress is predominant.