增程式電動車結構剛性設計與碰撞模擬分析

本論文主要探討增程式電動車白車體結構之剛性及耐撞能力。首先透過模態分析發現白車體結構因彎曲剛性不足而使電池盒模組產生局部振型，因此針對底鈑進行結構優化。將原始設計之底鈑橫樑改為補強縱樑後，提升了彎曲剛性且局部振型消失，並使彎曲剛性提升69.4%。接著進行整車碰撞模擬分析，進一步評估車體鈑件、銲點、幾合設計及材料性質等對抗碰撞能力之影響，以及車體變形過程是否對油箱、電池盒造成破壞。本研究將電阻點銲機械性質加入車體結構有限元素模型，使銲點在碰撞過程中產生失效。整車模型加入Hybrid III 50th百分位碰撞假人模型並以美國聯邦機動車輛安全標準進行整車前碰撞、側碰撞與後碰撞模擬分析，探討碰撞時假人損傷情形。前碰撞模擬分析，整車以時速35英哩初速撞擊剛體牆，駕駛頭部撞擊方向盤使頭部損傷指標超過法規規範，前大樑入侵乘客安全空間，使駕駛與副駕駛腿部均嚴重受損。側碰撞模擬分析則是移動台車以時速33.5英哩初速度撞擊受測車輛，駕駛胸腔側向加速度與後座乘客骨盆側向加速度超過法規規範。最後探討前方、側向與後方三種碰撞條件下，銲點失效、油箱與電池盒完整性，而整車銲點失效比率，前碰撞、側碰撞與後碰撞結果分別為22.58%、11.61%與14.34%，顯示銲點強度不足，無法使結構完整吸收能量，無法有效保護乘客安全，而油箱皆受到擠壓而有破裂之危險，電池盒模組無任何鈑件入侵或穿刺。

關鍵字

增程式電動車；模態分析；結構剛性；優化設計；碰撞模擬；銲點；假人；頭部損傷指標

並列摘要

This research investigates the structure stiffness and strength of the Body In White (BIW) of a Range-Extended Electric Vehicle. The original design of BIW shows a very low natural frequency of local bending mode, due to the improper design of cross-members which are used to install battery box as well as to reinforce the stiffness of floor. After redesign, the bending stiffness of BIW is increased up to 69.4%, and the local mode of bending is also disappeared. The impact crash simulations are then adopted to evaluate the crashworthiness of BIW, and the occupant safety. Hybrid III 50th Percentile dummy is included into the finite element model. Impact crash simulations are performed based on Federal Motor Vehicle Safety Standard. Welding strength is also evaluated in this study. In frontal impact simulation, the head injury criterion of driver exceeds maximum value, because driver’s head hits the steering wheel. Besides, the frontal main beam invades the occupant space; two dummies legs are seriously injured. In side impact simulation, the lateral acceleration of driver and rear passenger’s chests and pelvis are exceed maximum value. Finally, this research investigates the failure of spot welding and the integrity of the fuel tank and the battery box. The simulation results show the spot welding failure rate of frontal impact, side impact and rear impact were 22.58%, 11.61% and 14.34%, respectively. It means the strength of spot welding is too weak to integrate the structure strength. Furthermore, there are high risk of rupture of the fuel tank in each impact direction. There are no metal parts invade or puncture into the battery box.

並列關鍵字

Range-Extended Electric Vehicle ； Modal analysis ； Structure stiffness ； Optimization ； Impact crash simulation ； Spot welding ； Dummy ； Head injury criterion

參考文獻

[5] Zhang, Y., Wu, S., Shi, Y., Tu, J. et al., 2014, "Inclined Impact Test and Computer Simulation of Front Rail," SAE Technical Paper, 2014-01-0794.

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[7] Gopal Musale and Reza Keshtkar, 2005, "Versatile Occupant Analysis Model(V.O.A.M) for Frontal Impacts Using LS-DYNA and MADYMO," SAE Technical Paper, 2005-01-1000.

[8] Yonezawa, H., Tanaka, Y., Hosokawa, N., Matsui, Y. et al., 2010, "Occupant Responses in Child Restraint Systems Subjected to Full-Car Side Impact Tests," SAE Int. J. Passenge. Cars – Mech. Syst., Vol. 3(1), pp. 744-767

[11] Teng, T. L., and Wu, C. H., 2011, "Numerical Simulation of Side Impact Crashes," Information Technology Journal 10.

國際替代計量

增程式電動車結構剛性設計與碰撞模擬分析

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