桥梁段双层组合式安全护栏碰撞性能数值模拟

Numerical simulation evaluation of impact performance of double deck guardrail on bridge road section

为了得到"内层金属梁柱式+外层混凝土"的双层护栏组合的合理净间距范围,选择一辆总质量为50 t的半挂车和一辆总质量为8 t的轻型箱式货车作为代表性车型,进行不同净间距条件下的车辆与双层护栏数值模拟碰撞试验。结果表明:双层护栏净间距的最小值应大于内层金属护栏的高度;同时,净间距的最大值应不大于重载货车的驾驶室宽度,否则无法实现对失控半挂车的有效防护;内层护栏被8 t厢式货车撞击后结构保持完整,且具有良好的导出能力和侧翻抑制能力。

To obtain the reasonable range of the combination of double deck barrier ＂inner metal beam- column barrier ＋ external concrete barrier＂, Lb , three-dimensional solid models of a semi-trailer with a total mass of 50 t and a light van with total mass 8 t were established by software of Carla V5, and then input into Hypermeshl0.0, a CAE software. After mesh generation, mesh quality inspection, material property definition, constraint definitions and contact type definitions of moving parts, finite element mod- els of vehicles were obtained （ finite element models of guardrail were obtained by the same method）. After setting of crash conditions impacts of the vehicles on double deck guardrail with different net spacing were simulated by software of Ls-Dyna3d. The results of numerical experiments show that the minimum value of Lb should be greater than the height of inner beam-column barrier, that the maximum value should not be greater than the width of semitrailer＇s cab, and that inside barrier could remain undamaged after crashed by the light container vehicle, and has good capabilities of inducement and collision-resistant.