An accelerated algorithm for parameter identification in a hierarchical plasticity model accounting for material constraints

The parameter identification procedure proposed in this paper is based on the solution of an inverse problem, which relies on the minimization of an error function of least-squares type. The solution of the ensuing optimization problem, which is a constrained one owing to the presence of physical links between the optimization parameters, is performed by means of the particular technique of the feasible direction type, which is modified and improved when the problem turns to an unconstrained one. The algorithm is particularly efficient in the presence of hierarchical material models. The numerical properties of the proposed procedure are discussed and its behaviour is compared with usual optimization methods when applied to constrained and unconstrained problems.