The Improvement and Mechanism of Vehicle Rollover Subject to High Speed Side Collision

車輛翻覆為各種交通事故中嚴重性較高者之一，近年來由於多功能運動型車輛大為流行，該種車輛的翻覆事件也成為交通安全上的重要議題，因此有需要了解引發或加劇車輛翻覆之因素，以有效降低車輛之翻覆傾向。本研究利用參數化全車數值分析模型，並根據動量與能量守恆原理及撞擊測試資料作為輸入，分析在高速車輛受到側向撞擊後的動態行為反應。根據三種側向撞擊位置之車輛滾翻模擬結果，選用最大滾翻角度作為判斷翻覆傾向之指標，發現後撞擊點為使車輛翻覆傾向最大的撞擊位置，並據此探討車輛翻覆之機制及改善建議。此外，亦分析具有避震器變形加速度因素之阻尼力、增加高變形速度阻尼力以及交叉連通式等三種懸吊系統對高速車輛滾翻運動之抑制效果，其結果顯示，交叉連通式懸吊系統的效果最好，顯示低變形速度所對應之阻尼力較高變形速度者更能有效抑制滾翻運動。Rollover of vehicles is the main cause of severe and fatal injuries during car accidents on the road. In particular, owing to the advent of multi-purpose vehicles, it has become one of the important safety issues in recent years. It is important to realize the mechanisms that induce or aggravate vehicle rollover, and develop effective technology that is able to reduce the propensity of rollover. Using a parametric full-vehicle numerical model and impact force input estimated by the conservation law of energy and momentum from experiments in the literature, the research aims to analyze dynamic behaviors of oblique side collision for passenger vehicles on the highway. Levels of severity for various impact locations are investigated. Based on the results, the maximum roll angle is chosen as the index to represent the severity of vehicle rollover propensity and the most severe location is found to be the rear impact. Mechanisms of rollover under the most severe scenario are revealed by the established model. The strategies of rollover reduction are discussed and improvements are attempted according to the findings of this research. Effects of suspension deformation acceleration, higher damping at high deformation velocity and diagonally interconnected suspension under high speed side collision are compared. The diagonally interconnected suspension turns out to be the most effective system to reduce rollover propensity in which higher damping at low deformation velocity is more effective than that at high deformation velocity.口試委員會審定書 i謝 ii文摘要 iii文摘要 iv錄 v一章 緒論 1.1研究背景與動機 1.2文獻回顧 3.3研究方法與流程 8.4論文架構 9例 10二章 理論基礎 13.1前言 13.2車輛動力學模型 13.2.1拉格朗日方程式 13.2.2全車系統模型 14.2.3瞬時旋轉中心 18.2.4輪胎模型 20.2.5交叉連通式懸吊系統模型 22.3動量、角動量與能量守恆 23格 25例 29三章 實車模型與模擬情境 35.1前言 35.2全車數值分析模型之架構 35.2.1全車模型之組成 35.2.2避震器阻尼實測曲面模型 36.2.3典型路面模型 36.3模擬情境之設定 37.3.1撞擊情境 37.3.2側向撞擊力之估算 38.4車輛滾翻穩定性分析 40.4.1三種撞擊點之車輛動態運動行為反應 40.4.2滾翻分析指標與模擬情境之選定 40格 42例 43四章 車輛滾翻案例分析 49.1前言 49.2車輛翻覆機制分析 49.3三種懸吊系統對滾翻行為之影響分析 50.3.1避震器變形加速度 50.3.2高變形速度之阻尼增加 51.3.3交叉連通式懸吊系統 52.3.4三種懸吊系統之性能比較 53.4綜合建議 54例 57五章 結論及未來展望 65.1結論 65.2未來展望 66考文獻 6