An Experimental and Numerical Investigation on the Twist Springback of Transformation Induced Plasticity 780 Steel Based on Different Hardening Models

Abstract

Investigation on twist springback is important to improve the accuracy of forming parts. In this paper, a double C rail made of transformation induced plasticity 780 (TRIP 780) steel is designed, and the stamping and twist springback are simulated with ABAQUS based on three different hardening models (including Ziegler, Johnson-Cook and combined hardening models). A new index for calculating the twist springback is proposed, which is based on the angle between two end section lines of the double C rail. The experimental results of twist springback are compared with the calculation results from three different hardening models. The calculation results based on combined hardening model are the closest to the experiment data. In order to compensate twist springback, a curved surface die is designed based on the geometric shape of the double C rail after twist springback. The stamping and twist springback are simulated based on the curved surface die and combined hardening model, and the twist springback is decreased obviously after compensation, which shows that the compensation of twist springback is effective.