機車頭盔之撞擊模擬與分析

The Simulation and Analysis of Motor-Helmet during Impacting

陳永偉(Yung-Wei Chen)

指導教授 ： 洪興林

崑山科技大學/工程學院/機械工程研究所/碩士(2007年)

摘要

機車騎士頭、臉部傷害是一普遍而嚴重之交通事故，尤其台灣地區之發生率名列世界各國之冠，其潛在生命年數損失及社會成本極為龐大。避免機車騎士頭、臉部傷害，最有效的方法就是佩戴機車頭盔。為保有頭盔帽殼具一定的強度，頭盔須具有一定的厚度，而造成材料成本與重量的增加。為能製造出合乎市場、環境需求之製作成本要求低廉、經濟便宜且實用，更加堅固耐用之機車頭盔，經由正確之電腦模擬，以便了解撞擊時頭盔之動態行為是必要的。
本論文目的為依據E.C.E.標準撞擊測試程序，利用有限元素分析軟體(ANSYS/LS-DYNA)，研究頭盔在撞擊發生時之動態行為並找出最適當的頭型、墊料及帽殼三者之間的設計間隙。首先依據E.C.E標準撞擊測試結果，驗證電腦撞擊模擬的可靠性。再根據電腦模擬的數據，探討各種不同的頭盔間隙之撞擊結果的頭部傷害指數(Head Injury Criterion)及最大加速度值，以便評估於各種不同的頭盔間隙時，當頭盔承受衝擊時吸收動態能量及衝擊加速度值的能力。分析結果發現在平鉆測試中，頭型-保利龍之間隙越大其最大加速度就明顯越小、HIC值變化甚小。而保利龍-外殼之間隙越大其最大加速度變化些微、HIC值明顯變小。其原因為當間隙越大其變形緩衝區愈大。最後，經由分析結果和探討其間隙組合影響的趨勢並考量鉆墊及合理密合度情況下，建議較適當的設計間隙組合為頭型和墊料之設計間隙大約是5mm，而墊料和帽殼之設計間隙大約是7mm。

關鍵字

頭盔 ； 電腦模擬 ； 間隙

並列摘要

It is a general and serious traffic accident that motorcycle knight's head, face are injured, especially the incidence of Taiwan ranks the first of the countries all over the world, it is extremely huge that its potential life counts losses and social cost every year. When traffic accident occurs, the most effective method to protect motorcycle knight is to wear the helmet. In order to protect helmet cap shell, the helmet must have certain thickness, and cause the increase of the material cost and weight. With the purpose of decreasing of cost of manufacture which conform the market and environmental demand, sturdy and more durable motorcycle helmet, accurate computer simulation, in order to understand the dynamic behavior of the helmet is essential while striking.
By using the software (ANSYS/LS-DYNA), this purpose of this thesis was to investigate the dynamic behavior of the helmet while striking according to the E.C.E. testing standard procedure, and find out the design gap among head, liner and shell. Firstly, computer simulation accuracy was verified with the help of the E.C.E testing data, and then, the ability of helmet with different design gap to bears and absorbs dynamic energy, was studied by introducing Head injury criterion and maximum acceleration value during striking of helmet interval. The simulation results reveal that in flat anvil testing, when the gap of head - liner increases, maximum acceleration value becomes small obviously, and the values head injury criterion are similar closely. Moreover, it also shows that when the gap of liner - shell increases, maximum acceleration value is similar closely, and head injury criterion becomes small obviously. The reason of above results is the buffer zone of the contact becomes large when the gap increases. Finally, according to the simulation results and moderate fitness of helmet, it is recommended that the design gap of head - liner is about 5mm and the design gap of liner - shell is about 7mm, respectively.

並列關鍵字

Helmet ； Computer simulation ； Gap

參考文獻

[5]FMVSS 218 Motorcycle helmets: Federal Motor Vehicle Safety Standard, Washington 1992.

[7]British Standard 6658, "Protective helmets for vehicle users", British Standard Institution, London , 1985 .

[8]E.C.E. R 22, 〝Uniform provisions concerning the approval of protective helmets and of their visors for drivers and passengers of motorcycles and mopeds , Geneva, 1995.

[10]C. W. Gadd, "Use of a weighted impulse criterion for estimating injury hazard", 10th Stapp Car Crash Conference Proceedings, Socity of Automotive Engineers. : 95-100, 1966.

[14]N. J. Mills and A . Gilchrist, “The effectiveness of foams in bicycle and motorcycle helmets , ”Accident Analysis & Prevention 1991;23 ( 2 / 3 ) : 153-163 .