汽車輕量化為設計者設計目標之一，而在低速碰撞中，保險桿對車身的安全防護作用是不容忽視的，針對保險桿的要求，希望能在材料使用最少的情況之下，依然能製作出具有良好耐撞性的保險桿來通過要求的規範。
本研究的重點主要是以現行量產車作為基礎進行保險桿不等厚度研究, 透過流程的建構，一開始材料測試取得材料參數性質，再來針對廠商提供的剛性測試基準來劃分保險桿各個區域，依照相對應的剛性基準找出最佳厚度值來完成不等厚度設計，過程中著重於保險桿材料碰撞特性與現行法規的研究，採實驗及模擬相互驗證，來獲得最適用的材料性質，再利用所得材料性質以期達最佳的保桿系統基礎模型。
本研究另一個貢獻在保險桿厚度設計過程中，將模擬軟體與程式語言做結合，並將最佳化方法應用在其中，加速保險桿厚度設計流程降低時間成本，提供設計者在保險桿厚度設計上有個初步的參考依據來製作保險桿。
本研究最後部分，則是將新舊保險桿根據ECE R42法規來做撞擊模擬，比較新舊保險桿差異性來做討論，藉由比較提供設計者了解保險桿在動態行為的表現，而對保險桿厚度設計能有更多不同的考量方向。

A lightweight vehicle is a recent trend for automotive design due to energy shortage problems. The reduction of vehicle weight can be achieved by redesigning its parts. The bumper system is among them and is our main focus in this study. However, the safety of the vehicle can not be sacrificed and the modified bumper has to pass the current safety regulation. In this study, a design procedure is carried out for a bumper system which is fabricated by least materials and still capable of maintaining good crashworthiness to protect itself and occupants inside during a low-speed impact.

The main goal of this study is to determine optimal thickness for a bumper of an on-market vehicle. Base on the thickness determination, the lightweight purpose can be achieved. At the starting procedure, the property of the bumper is obtained by standard material experiments. Based on the results, the regional stiffness test for the bumper was conducted based on finite element method. According to the empirical regional stiffness standard, the optimal thickness of the bumper in each region can be determined. In the end, the newly modified bumper has to be validated by the current safety regulation. In this study, the ECE R42 is used as safety regulation and the finite element method is applied to conduct the validation. In order to accelerate the design procedure, the interface codes between the commercial engineering software and the optimal program is written in the study.

Finally, two vehicle models are utilized to validate the newly developed procedure in this study. The discrepancy between the original and modified designs is compared and discussed. The result show the procedure is capable of reducing the bumper weight without sacrificing its safety.

Keywords: bumper, bending test, finite element method, low-speed impact

ANSYS, (2009) ANSYS Verification Manual, ANSYS Inc., Pittsburg, PA, USA.
Arora, J. (2004) Introduction to Optimun Design, Elsevier, IOWA, USA.
ECE-R42 (1980) “Uniform Provisions Concerning the Approval of Vehicles with Regard to Their Front and Rear Protective Devices,”
Gong, Y.X., Shen, X.H. and Nie, X.J. (2007) “Bumper Crash Simulation Study at Low Speed on Abaqus,” Natural Science Edition, Vol. 4, No. 3, pp. 32-36.
Laia, R.V. and Enderich, T. (2007) “Advanced Simulation Techniques for Low Speed Vehicle Impacts,” LS-DYNA Anwenderforum, Frankenthal, pp. 25-35.
LS-DYNA, (2009) Keyword User’s Manual Version 971, Livermore Software Technology Corporation.
Marzbanrad, J. Alijanpour, M. and Kiasat, M.S. (2009), “Design and analysis of an automotive bumper beam in low-speed frontal crashes,” Journal of thin-walled structures, pp. 902-911.
MATLAB, (2007) MATLAB Reference Guide, The Mathworks,Inc., Natick, MA, USA.
NCAC, (2000) Finite Element Model Archieve,
http://www.ncac.gwu.edu/vml/models.html
Sapuan, S.M., Maleque, M.A., Hameedullah, M., Suddin, M.N. and Ismail, N. (2004) “A note on the conceptual design of polymeric composite automotive bumper system,” Journal of Materials Processing Technology, pp. 145-151.
Shah, V. (1951) Handbook of Plastics Testing Technology 2nd ed., Canada.
Zhang, Z.W. (2007) “Impact Performance Analysis of Front Bumper in Low Speed,” Vocation and Technical Institute of Transportation Zhejiang University of Technology, China.
羅文翔，(2007) “三點彎曲方式量測陽極氧化鋁模板機械性質與破斷面分析之研究” 碩士論文，國立交通大學材料科學與工程學系。