Calibration of a combined isotropic‐kinematic hardening material model for the simulation of thin electrical steel sheets subjected to cyclic loading

Abstract

The combined isotropic‐kinematic hardening model enables the description of the cyclic transient elastic‐plastic material behaviour of steel. However, the determination of the material model parameters and understanding of their influence on the material response can be a challenging task. This study deals with the individual steps of the material model calibration for the simulation of thin electrical steel sheets under cyclic loading. Specific recommendations are made for the determination of kinematic and isotropic hardening material parameters. In particular, the isotropic hardening evolution is described by Voce's exponential law and a simple multilinear approach. Based on the multilinear approach, which allows for different slopes in the evolution of the yield surface size, an alternative calibration of the isotropic hardening component is proposed. As a result, the presence of the yield plateau in the first half cycle can be accurately captured, while convergence issues in the material model definition for numerical simulations can be avoided. The comparison of simulated load cycles with experimental cyclic tests shows a good agreement, which indicates the suitability of the proposed material model calibration for electrical steel.

Modelling and simulation of the hardness profile and its effect on the stress‐strain behaviour of punched electrical steel sheets

“…Finally, the validation by means of experimental true stress-strain curves indicates the correct representation of the relations between hardness and elastic-plastic material properties. In further works, an extension of the modelling approach for the simulation of cyclic loading would be conceivable using a suitable hardening model as presented elsewhere [44].…”