2024 Volume 80 Issue 13 Article ID: 23-13158
An analytical approach that can reproduce the cyclic behavior of ERW steel pipe columns, where significant residual plastic strains occur during the manufacturing process, was investigated. As a result, several requirements for conducting accurate analyses became evident. Firstly, it is necessary to employ the geometrically and materially nonlinear FE shell model capable of representing the cyclic local buckling behavior of steel pipes in the large plastic strain region. Therefore, the modified three-surface model with the expanding bounding surface that had been proposed by authors was utilized herein as the constitutive model of the steel pipe. Secondly, it is crucial to accurately predict the generated residual plastic strains by the shell FE analysis, considering the pipe manufacturing process. Then, these predicted residual plastic stains are explicitly introduced into the FE shell model of steel pipes with their virgin material. When the constitutive laws of the virgin material are unknown, a method for estimating the constitutive laws of the virgin material through inverse analysis has been proposed. In the inverse analysis, suitable constitutive laws for the virgin material are identified so that the tensile coupon test results of the pipes can be represented by an FE model that incorporates the calculated residual strains.
