An inverse finite element analysis applied to rheological parameter identification

To improve the values of rheological coefficients, parametric identification must be formulated as a distinct category of inverse problems, involving the usual stages. The cost function is expressed as the difference, in a least square sense, between the finite element results and the experimental observations for a set of operating conditions during rheological tests. The identification procedure is based on a modified Gauss-Newton method using an accurate evaluation of the matrix sensitivity derived from the direct differentiation of governing equations with respect to the parameters. After having describe the numerical framework of this approach, results concerning the analysis of tensile and torsion tests are presented.