Combined elastoplastic finite element method and tube tensile test method to accurately characterize flow behaviors of tubular metallic materials

Abstract

An efficient and practical method of the combined elastoplastic finite element method (FEM) and tube tensile test method (CF3TM) for obtaining accurate flow curves of tubular materials is presented. The CF3TM iteratively reduces the difference in the tube tensile load at the selected sample points between the finite element (FE) predictions obtained using the piecewise linear function flow (PLFF) model of effective strain and their corresponding experiments. Due to the nature of the tubular material, a snug-fitting plug is inserted to reinforce the grips, and the outer skin of the major elongation section is appropriately turned to divide the tubular material into a deformable body section and a strong grip section. The difference between the FE analysis model and the actual tube tensile test is minimized using a multi-body analysis model of the plug and the material. The CF3TM is applied to the SUS 304 tubular material. As a result, starting from the initial flow curve with an average error of 26.5% based on the tube tensile load, a flow function providing a tube tensile test prediction result with an average error of less than 0.16% is obtained with only two iterative calculations.