ESTIMATION OF MATERIAL PARAMETERS AT ELEVATED TEMPERATURES BY INVERSE MODELLING OF A GLEEBLE EXPERIMENT

摘要

A method for estimation of inelastic material parameters from Gleeble experiments is presented. Material parameters at elevated temperatures are estimated by inverse modelling of a Gleeble compression test during continuous cooling. The direct problem is solved using the implicit finite element program NIKE2D. The material behaviour is described by a rate independent thermo-elastic-plastic model with a nonlinear isotropic hardening law. The objective function is formed based on the discrepancy in force-displacement data between the numerical model prediction and the experiment. Minimisation of the objective function with respect to the material parameters is performed using an in-house optimisation software shell which is built on the subplex method. A Gleeble experiment with different deformation and temperature histories has been used for validation of the computed parameters. The validation experiment is simulated using both the material parameters achieved through inverse modelling and traditional estimation methods. The analysis showed better agreement when using the parameters estimated by the numerical method presented in this paper.