應用剪刀試驗於DP980高強度鋼之Yoshida-Uemori材料模型研究

APPLICATION OF SHEAR TESTS TO THE YOSHIDA-UEMORI MATERIAL MODEL FOR DP980 HIGH-STRENGTH STEEL

張志毅(Chih-Yi Chang)；何明雄(Ming-Hsiung Ho)

Yoshida-Uemori 材料模型 ； 剪力試驗 ； 沖壓成形 ； 回彈 ； Yoshida-Uemori material model ； shear test ； stamp forming ； springback

桃園創新學報

35期（2015 / 12 / 01）

49 - 66

繁體中文

在節能與耐衝擊的要求下，高強度鋼逐漸成為汽車鈑件的重要材料，然而在金屬沖壓成形的製程中，高強度鋼板的回彈量遠大於一般軟鋼板，使得沖壓成形的數值模擬與預測變得非常困難。Yoshida-Uemori 材料模型能夠完整地描述金屬在循環大塑性變形下的包辛格效應與應變硬化行為，是目前高強度鋼沖壓成形模擬的重要材料模型，本文將藉由往復式剪力試驗探討如何建立高強度鋼DP980 之Y-U材料模型，並透過LS-DYNA 數值模擬驗證其正確性，接著建立NUMISHEET’93沖壓實驗，再以DYNAFORM 模擬驗證本文所獲得之Y-U 材料模型確實可用於沖壓回彈之模擬。

The drive toward energy conservation and impact resistance has increased the importance of high-strength steel sheet components in the automotive industry. However, during metal stamp forming, springback associated with high-strength steel is far more pronounced than that observed in common mild steel. As a result, the numerical simulations and obtaining accurate predictions related to stamp forming results can be extremely difficult. The Yoshida-Uemori (Y-U) material model is currently an important model in the simulation of stamp forming high-strength steel with the ability to comprehensively describe the Bauschinger effect and strain hardening behavior of metal during severe plastic deformation. This study utilized cyclic shear tests to investigate the development of a Y-U material model for DP980 high-strength steel. LS-DYNA numerical simulations were used to verify the accuracy prior to conducting NUMISHEET’93 stamp forming experiments and DYNAFORM simulations. Our results demonstrate that Y-U model parameters derived in this study can be used to provide accurate simulations of the springback associated with stamp forming high-strength steel.