Instability strain and shear band spacing in simple tensile/compressive deformations of thermoviscoplastic materials

摘要: Abstract We analyze the stability of homogeneous simple tensile/compressive deformations an isotropic heat-conducting thermoviscoplastic bar by studying growth infinitesimal perturbations superimposed upon a deformation. The smallest axial strain at which perturbation has positive initial rate is called instability strain. Two criteria are used to determine shear band spacing; (i) wave number, ξ m , that maximum gives spacing, L s = 2 π / between adjacent bands, and (ii) inf t 0 ⩾ ( ) where time when solution perturbed. It found geometric softening/hardening significantly affects value . effect varying thermal conductivity, strain-rate hardening exponent average on been delineated. ∝ nominal - 0.757 However, for conductivity χ ¯ strongly depends No scaling law Taylor–Quinney parameter. For specific heat increases monotonically with increase in