CONSTITUTIVE PARAMETER SENSITIVITY IN ELASTOPLASTICITY

The paper presents equations and algorithms for numerical computation of elasto-plastic and elasto-viscoplastic constitutive parameter sensi tivity problems. The general integration idea is based on the return-m apping algorithm. Two viscoplastic constitutive models are discussed i n details: the overstress (Perzyna) model and the power law strain and strain-rate hardening model. The use of the consistent tangent operat or is shown to be essential for the accuracy of the sensitivity analys is. A possible discontinuity of sensitivity at the transition (yield l imit) point is discussed. It is concluded that in principle the nonuni queness of the sensitivity solutions at such points does not invalidat e the general idea of sensitivity calculations. A number of numerical examples illustrate the theoretical considerations.