以基礎載具分析先進高強度鋼板扭曲現象之研究

Abstract

近年來隨著溫室效應的日趨嚴重以及民眾環保意識的覺醒，國際間各車廠紛紛投入車體輕量化之研究以達成降低二氧化碳排放量的目標，因此汽車結構件使用具備輕量化及高強度化之先進高強度鋼板已成為共同之趨勢。然而，隨著鋼板強度的提升，先進高強度鋼板在成形上會更加困難，且側壁外開、側壁捲曲及扭曲等成形缺陷亦會更加嚴重。本研究將針對回彈情況較複雜之扭曲缺陷進行探討與改善。 本研究首先根據扭曲相關文獻進行歸納整理，得出具轉折角度之結構件為最容易產生扭曲缺陷之不對稱特徵造型。接著藉由分析Curved hat channel模具與S-rail兩種基礎載具模型來探討先進高強度鋼板之扭曲現象。本研究參考Curved hat channel模具之基礎造型，提出一扭曲量與其造型參數之理論關係式，且建立各造型參數與扭曲量之關係，可提供開發者日後在設計仿Curved hat channel之實際載具(如A柱)時初步挑選合適的搭配參數方向。本研究亦建立S-rail模具沖壓先進高強度鋼板之CAE分析模型，實際分析各造型參數與扭曲量之關係，可提供開發者日後在設計仿S-rail之實際載具時初步挑選合適的搭配參數方向。最後優化設計了一套可提升實驗效率之驗證模具，未來可實際執行沖壓試驗驗證先前建立之先進高強度鋼板材料模型對於扭曲回彈預測之準確性，並將此材料模型持續應用於後續之模擬研究。

As greenhouse effect becomes worse and environmental consciousness rises in recent years, there are more and more vehicle manufacturers around the world starting to study lightweight design of automobiles in order to reduce CO2 emissions. It results in widely use of advanced high strength steels (AHSS) in automobile structural parts because of its lightweight and high strength. However, the higher strength the sheet metal, the harder to stamp. In addition, the stamping defects such as sidewall curl and distortion become worse. This research aims to investigates the more distortion defects in deep drawing of AHSS. It is known that structural parts with turning geometry are easier to generate distortion defects because of its unsymmetry. This thesis investigates distortion phonemenon of AHSS DP980 steels by two fundamental model, Curved hat channel and S-rail die. First, this thesis studies propose the relation among geometric parameters and twist angle. The results can provide a direction for designers to design structural parts like A-pillar. The research also builts CAE model of Curved Hat Channel and S-rail model, and establishes relations between all parameters and twist angle. Finally, a S-rail die is made for CAE model validation. The experiments will carry out in the future. And the material model of DP980 can also apply for other CAE process ine the future.