Tensile plasticity and ductile fracture

A mathematical model of tensile plasticity and void growth based on the Gurson flow surface and associated flow law is developed and applied to the problem of ductile fracture under general tensile loading conditions. The flow surface defines the plastic strain components in the tensile region; conditions of fracture are defined in terms of the plastic deformational strain, porosity, and the ratio of mean stress to shear stress, p/τ. This model reduces to the Carroll and Holt [J. Appl. Phys. 43, 759 (1972)] tensile threshold pressure for void growth, and to the Rice and Tracey [J. Mech. Phys. Solids 17, 201 (1969)] expression relating the fractional change in void radius to the incremental plastic deformational strain and p/τ in a triaxial tensile stress field. The model has sufficient generality to represent plastic flow and fracture in notched and smooth tensile bars as well as in uniaxial‐strain spallation tests. One‐ and two‐dimensional finite‐difference calculations demonstrate this capability.

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