Viscoplasticity for instabilities due to strain softening and strain-rate softening

Strain Numerical analysis Model Instability Mechanical Shear band Plasticity Initial value problems Convergence Shear Stiffness Civil Instabilities Loading Hardening Softening Stiffness Matrix MODELS A4630J Viscoelasticity, plasticity, viscoplasticity, creep, and stress relaxation A0260 Numerical approximation and analysis Strain softening Strain-softening A6220F Deformation and plasticity Softening metallurgical Plastic Deformation Mechanical stability A0230 Function theory, analysis A4630L Buckling and instability Algorithmic treatment Consistency model Consistency viscoplastic approach Duvaut Lions model Global convergence Hardening effects Initial value problem Length scales Limited numerical experience Overstress viscoplastic models Perzyna model Rate dependent yield surface Regularising effect S type instabilities Shear deformation Softening problems Standard Kuhn Tucker conditions Strain rate softening Tangential stiffness matrix