Volume 11 Issue 3
Effect of Constitutive Equations on Springback Prediction Accuracy in the TRIP1180 Cold Stamping
Ki-Young Seo, Jae-Hong Kim, Hyun-Seok Lee, Ji Hoon Kim and Byung-Min Kim
1Division of Precision and Manufacturing Systems, Pusan National University, Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 609-735, Korea
2Press Die Research Team, Nara Mold & Die Co. Ltd., Gongdan-ro 675, Seongsan-gu, Changwon-City, Gyeongnam 642-120, Korea
3School of Mechanical Engineering, Pusan National University, Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 609-735, Korea
*Author to whom correspondence should be addressed.
Abstract
This study aimed to evaluate the effect of constitutive equations on springback prediction accuracy in cold stamping with various deformation modes. This study investigated the ability of two yield functions to describe the yield behavior: Hill’48 and Yld2000-2d. Isotropic and kinematic hardening models based on the Yoshida-Uemori model were adopted to describe the hardening behavior. The chord modulus model was used to calculate the degradation of the elastic modulus that occurred during plastic loading. Various material tests (such as uniaxial tension, tension-compression, loading-unloading, and hydraulic bulging tests) were conducted to determine the material parameters of the models. The parameters thus obtained were implemented in a springback prediction finite element (FE) simulation, and the results were compared to experimental data. The springback prediction accuracy was evaluated using U-bending and T-shape drawing. The constitutive equations wielded significant influence over the springback prediction accuracy. This demonstrates the importance of selecting appropriate constitutive equations that accurately describe the material behaviors in FE simulations.
Keywords:advanced high-strength steel; yield function; hardening model; springback; deformation mode