山区公路混凝土护栏碰撞特性仿真分析

为探明山区公路上常用的间断式混凝土护栏及连续式混凝土护栏的碰撞特性,基于动态显式有限元方法及VPG软件,建立了完整的汽车-护栏-乘员-座椅-安全带一体化模型,对四种典型山区公路护栏进行了碰撞仿真分析。发现汽车撞击间断式混凝土护栏时,出现混凝土墩拌阻车轮的现象,甚至出现汽车的右前轮被护栏完全刮脱的情况,不仅假人头部及胸部遭受剧烈冲击,而且驾驶室变形严重;而汽车撞击连续式混凝土护栏时,车辆的左后轮出现了明显的抬高现象,表明车辆存在倾翻的趋势,但车辆尾部的高度变化曲线表明,车辆左后轮在抬高到一定高度后,将不再继续抬高,并逐步返回地面,说明车辆尾部的高度变化趋势是趋于稳定的;当护栏底部凸缘高为80mm时,出现前轮可以顺利爬上并溜下护栏斜坡,而后轮无法爬上护栏斜坡的现象;当护栏底部凸缘高为150mm时,则车辆的前、后轮均不能爬上护栏斜坡。结果表明,间断式混凝土护栏存在的主要问题是对失控车辆的诱导能力不足;连续式混凝土护栏存在的主要问题是护栏底部的凸缘太高,护栏的主要尺寸参数需要优化。

Simulation analysis for collision characteristics of concrete barriers on montane highway

In order to explore the collision characteristics of interrupted type and continuous type concrete barriers on montane highway, a integrated model of automobile-barrier-passenger-seat-safety belt was established by dynamic explicit finite element method(EFEM) and VPG software. The collision process analysis for four kinds of typical montane highway concrete barriers was carried out. It is pointed that when interrupted type concrete barrier is crashed by truck, concrete frusta blocks wheel, even right front wheel is divorced from truck, dummy's head and chest suffer from violent impact, and cab deformation is severe; however, when continuous type concrete barrier is crashed by truck, the hoist phenomenon of left rear wheel and the turning over trend of truck are obvious, but the height variety curve of truck tail shows that the hoist of left rear wheel does not continue over a certain height, and the wheel return to ground gradually, that's to say, the height variety trend of truck tail is stability; as the height of convex barrier flange at bottom is 80 mm, the front wheel of truck can smoothly climb up and slip away concrete barrier slope, but the rear wheel of truck can't climb up concrete barrier slope; while the height of convex barrier flange at bottom is 150 mm, the front wheel and rear wheel of truck can't climb up concrete barrier slope. Analysis result indicates that interrupted type concrete barrier is short of inducing ability to losing control vehicle, the convex flange of continuous type concrete barrier at bottom is too high to be climbed by truck, and it's necessary to optimize its main structure parameters. 1 tab, 16 figs, 15 refs.