A method for thermo-mechanical analysis of steady state dynamic crack growth

Abstract

Cracks propagating at high speeds in metals generate heat at their tips which cannot be conducted away in the very short time span of crack growth. The effect of heating on the crack tip stress fields and on dynamic fracture toughness is analyzed using a method based on the theory of generalized analytic functions. In this method all deviations from a linear elastic, homogeneous strain field are represented as fictitious body forces, allowing one to model inelastic and thermal effects. Numerical computations of the crack tip stress and strain fields are performed assuming steady-state, plane stress, mode-I dynamic crack growth with a fixed crack tip temperature field, but with temperature and strain rate sensitive mechanical properties. The relationship between dynamic stress intensity factor and crack velocity has been determined using competing ductile and brittle fracture criteria. A careful analysis of the trailing wake has been performed to study its effect on the crack tip stress field.