冲击速度对带支撑钢构格栅坝抗冲击性能的影响

摘要

带支撑钢构格栅坝在拦截大石块，减小泥石流冲击破坏中有十分重要的作用。利用非线性有限元软件 ANSYS/LS-DYNA 对带支撑钢构格栅坝结构模型进行数值模拟。用钢球模拟巨石，以不同的冲击速度在格栅坝中间榀顶层梁柱节点施加冲击荷载，分析在冲击荷载作用下结构的动力响应。结果表明：带支撑钢构格栅坝各处位移随着钢球冲击速度的增加逐渐增大，基本呈现线性变化的规律，尤其在冲击作用点处结构的位移变化率最大，且距冲击作用位置越远位移变化率越小；结构各处应力值随着冲击速度的增加而增大，且距冲击作用位置较远的单元应力变化接近线性增长规律；随着冲击速度的提升，结构各柱脚支反力逐渐增大。%The steel grilled dam with support plays an important role in holding up ratchel and reducing debris flow impact damage.This paper takes the supporting steel grille dam structure as model and uses nonlinear finite element software ANSYS/ LS-DYNA to make numerical simulation.It uses the steel ball to stimulate the rock,taking different impact speed to apply impact loading in the trusses top beam-column joints of the grilled dam,and makes analysis of the structure's dynamic response under the effect of impact load.The results show that:the displacement of steel grilled dam with support increases with the increase of steel ball's impact speed,showing the law of linear variation.In particular,the displacement changing rate is the largest in the impact point.And the farther from the impact position,the smaller of the displacement changing rate.The stress value of the structure increases with the increase of impact speed,and the unit stress change that far form the impact position is close to the rule of linear growth;The pillar bearing reac-tion of the structure increases with enhancement of the impact speed.