| Summary: | 碩士 === 國立屏東科技大學 === 車輛工程系所 === 103 === 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.
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