Viscoplastic finite element analysis by automatic subincrementing technique

An automatic subincrementing technique for numerical integration of viscoplastic constitutive rate equations is investigated for finite element analysis. The technique has two major features: estimate of error and determination of time subincrements for the evaluation of inelastic strains and associated state variables at a material point. For numerical expediency, explicit integration formulas are preferred over the implicit schemes. Numerical experiments for both low and higher order Runge-Kutta explicit methods are performed. Numerical results indicate that the Euler method appears to be more suitable for the automatic subincrementing procedure. Three examples are included to illustrate the analysis capability of the procedure investigated.