Summary
The presented method to identify material parameters for inelastic deformation laws is based on the numerical analysis of inhomogeneous stress and strain fields received from suitable experiments. Tensile and bending tests were carried out to obtain elastic and hardening parameters. The deformation law for small elasto-plastic strains is presented as a system of nonlinear differential and algebraic equations (DAE) consisting of the stress–strain relation, evolution equations for the internal variables and the yield condition. Different rules for the evolution equations of isotropic, kinematic and distorsional hardening are proposed. The DAE are discretized using an implicit Euler method, and the resulting system of nonlinear algebraic equations is solved using the Newton method. Deterministic optimization procedures are preferred to identify material parameters from a least-squares functional of numerical and measured comparative quantities. The gradient of the objective function was calculated using a semianalytical sensitivity analysis. Due to measurement errors, the optimal sets of material parameters are non unique. The approximate estimation of confidence regions and the calculation of correlation coefficients is presented.
The results of several optimization processes for material parameters of elasto-plastic deformation laws show a good agreement between measured and calculated values, but they show also problems which may occur if systematic errors will not be recognized and deleted.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received 30 September 1999; accepted for publication 8 March 2000
Rights and permissions
About this article
Cite this article
Kreißig, R., Benedix, U. & Görke, UJ. Statistical aspects of the identification of material parameters for elasto-plastic models. Archive of Applied Mechanics 71, 123–134 (2001). https://doi.org/10.1007/s004190000106
Issue Date:
DOI: https://doi.org/10.1007/s004190000106