| 摘要: | 近年來全球環保意識抬頭，為了減少溫室氣體的排放，並提昇燃油效率，汽車減重為各大汽車廠努力的目標，世界各國也將碳排放做為主要環保指標；首當其衝的就是車輛油耗表現，從而使得高強度鋼材(Advance High Strength Steel) 的使用增加；而其中使用量最為廣泛的就是雙相鋼(Dual Phase Steel)。
在車輛零件生產過程時會有材料會有回彈效應的現象產生；這也是汽車產業目前對於此種材料在進行生產時會遇到的難題；特別在零件尺寸的成型精確度上。然而在沖壓成型中，回彈為無法避免的問題，且隨著使用之材料的強度愈高，回彈現象愈嚴重，故本研究採用三點鈑彎、U 型彎曲以及V型彎曲成型實驗來了解回彈之特性，選用1mm厚度的薄板雙相鋼DP590、雙相鋼DP780、雙相鋼DP980和雙相鋼DP1180四種材料來了解高強度鋼板在回彈現象的差異性。
本研究使用油壓式壓床與曲柄式沖壓機來探討先進高張力鋼在不同應變率下之成型特性及不同應變率與板件破裂之關係，並希望從中探討是否以不同模具尺寸、模具特性來抑制回彈之可行性。並利用有限元素法軟體模擬高強度鋼板回彈之行為，驗證CAE 模擬回彈之正確性。為了提升CAE 模擬回彈之正確性，本研究將探討不同應變程度與回彈角度的關係，再將其應用於基本造型沖壓成型CAE 模擬分析技術上，包括V 型彎曲成型、三點鈑彎及U 型彎曲。
雙相鋼因為材料變形時相變態的緣故會強化，本研究針對這個強化現象分析板材成型時雙相鋼的回彈角度變化，以及改變製程參數對回彈角度的影響。;In recent years, the awareness of global environmental protection.In order to cut greenhouse gas emissions, increase the fuel efficiency of gasoline. Losing weight of automobile is the goal of each automotive company in the world. Carbon emissions becomes major environmental index for each country in the world. Thus increased usage of advanced high strength steel. However, there is dual phase steel is the most used material.
In the production process of vehicle parts, there will be a phenomenon that the material will have a springback effect, this is also the problem that the automotive industry currently encounters in the production of advanced high strength steel, especially in the accuracy of forming the part size. However, in stamping forming, springback is an unavoidable problem, and as the strength of the material used is higher, the springback phenomenon becomes more serious, so this study uses three-point sheet bending, U-bending and V-bending forming experiments to understand the characteristics of springback.After all, we choose four materials of 1mm thickness thin-plate dual-phase steel DP590, dual-phase steel DP780, dual-phase steel DP980, and dual-phase steel DP1180.
In this study, hydraulic presses and crank presses were used to discuss the forming characteristics of advanced high strength steel under different strain rate and the relationship between different strain rate and plate breakage. We hope to discuss the possibility, whether to use different die size and die characteristics to suppressing the of springback. And using the finite element method software to simulate advanced high strength steel springback to verify the correctness of CAE simulated springback. In order to improve the accuracy of CAE simulation springback, this study will explore the relationship between the degree of same
strain and springback angle, and then apply it to the basic analysis of CAE simulation analysis technology of stamping forming, including V-shaped bending, three-point sheet bending and U-shaped bend.
The dual-phase steel will be strengthened due to the phase transformation when the material is deformed. In this study, the springback angle of the dual-phase steel during sheet forming and the effect of changing the process parameters on the springback angle are analyzed for this strengthening phenomenon. |
