六边形结构桥墩柔性防撞装置等效弹性系数研究

Study on Equivalent Elastic Coefficient of a Hexagon-shape Crashworthy Device for Bridge Piers

针对我国自主研发的桥梁柔性防撞装置,引入等效弹性系数研究其结构响应,并构建物理模型:2个六边形结构的钢围环绕在桥墩上,钢围之间由均布弹簧圈支撑连接.利用弹性地基梁理论分析该模型在小变形情况下的力学响应,通过解微分方程确定平动情况下该模型的等效弹性系数.研究表明:等效弹性系数是关于六边形结构几何参数、弹簧弹性系数、钢围抗弯刚度、撞击力的作用点位置的函数;在外钢围没有塌陷的情况下,结构的几何参数对于等效弹性系数的影响最大;装置的等效抗弯刚度超过0.25时,外钢围近似认为刚性;而在远远小于0.25时,在撞击点附近外钢围发生塌陷.

The equivalent elastic coefficient （EEC） is crashworthy system which is developed independently introduced to study the structure response of the flexible in China. The physical model is built, which is composed of distributed springs linking and supporting two hexagonal-shape box-beam structures that encircle the bridge pier. Based on the elastic foundation theory, the mechanical response equation is derived in the case of small strain. By solving the differential equation, the translational equivalent stiffness of the model is identified. The result shows that EEC is the function of the geometric parameter of the hexagonal-shape structure（HSP）, the elastic coefficient of the spring, the bending stiffness of the box beam, and the location of the impact point; When the outer box beam is in stable state, HSP has the largest effect on EEC; When the equivalent bending rigidity of the outer box beam is about 0.25, the box beam can be considered as a rigid one, and when the rigidity is far below 0.25, the collapse of the box beam is to happen around the location of the impact point.