Estimation of Numerical Model Parameters for Cyclic Behavior of Structural Steel Material

Abstract

To evaluate the structure accurately by using finite element analysis (FEA), definition of material model is important. Especially, under seismic and wind load, the structural member suffers cyclic load, therefore material model should describe cyclic behavior in plastic range. However, there is a difficulty in determining the material parameters because the constitutive equation contains a lot of parameters and cyclic material test shall be conducted to determine the parameters. In this study, monotonic and cyclic material test were conducted to investigate nonlinear behaviors of various grade of steel. Moreover, the test data from previous studies was collected. To simulate material behavior, Chaboche combined hardening model was adopted and optimization method was used to determine its parameters. Particle swarm optimization (PSO) was used to minimize the objective function that is difference between experiment and analysis results. Furthermore, a prediction equation of each parameter are proposed, which have only monotonic mechanical properties.