
Accession Number : ADA138273
Title : Plastic Deformations Near a Rapidly Propagating Crack Tip.
Descriptive Note : Interim rept.,
Corporate Author : NORTHWESTERN UNIV EVANSTON IL STRUCTURAL MECHANICS LAB
Personal Author(s) : Achenbach,J D ; Li,Z L
PDF Url : ADA138273
Report Date : Jan 1984
Pagination or Media Count : 47
Abstract : For rapid crack propagation in an elastic perfectlyplastic material, explicit expressions have been obtained for the dynamic strains on the crack line, from the moving crack tip to the moving elasticplastic boundary. The method of solution uses power series in the distance to the crack line, with coefficients which depends on the distance to the crack tip. Substitution of the expansions in the equations of motion, the yield condition (HuberMises) and the stressstrain relation, yields a system of nonlinear ordinary different equations for the coefficients. These equations are exactly solvable for ModeIII, and they have been solved in an approximate manner for ModeI plane stress. The crackline fields have been matched to appropriate elastic fields at the elasticplastic boundary. For both ModeIII and ModeI plane stress, the plastic strains, which depend on the elastodynamic stress intensity factor and the cracktip speed, have been used in conjunction with the crack growth criterion of critical plastic strain, to determine the relation between the farfield stress level and the cracktip speed. (Author)
Descriptors : *Plastic deformation, *Crack propagation, *Equations, *Stress concentration, Quick reaction, Elastic properties, Power series, Strain hardening, Nonlinear differential equations, Coefficients, Stress strain relations, Plastic properties, Equations of motion, Front ends and surfaces
Subject Categories : Numerical Mathematics
Mechanics
Solid State Physics
Distribution Statement : APPROVED FOR PUBLIC RELEASE