摩擦型高强螺栓传力性能及缺失的非线性分析

Nonlinear analysis on load-transfer performance and bolt missing of frictional high strength bolted connections

针对钢桁梁桥摩擦型高强螺栓连接出现的螺栓缺失问题,利用ANSYS软件,采用壳单元模拟连接板件,弹簧单元模拟接触面相互作用,对摩擦型高强螺栓连接进行了设计状态和螺栓缺失状态下的非线性有限元分析。结果表明:摩擦型高强螺栓连接发生滑移后,外荷载与螺栓所传剪力之间呈现非线性关系;在无滑移状态,各螺栓所传剪力沿外力方向和其垂直方向均为外侧大,中间小,滑移后趋向均匀;随螺栓缺失个数的增加,螺栓群初始滑移荷载、极限滑移荷载和缺失排螺栓传力比均减小,无滑移和局部滑移时相邻排增大最明显,全面滑移后其余各排则同等增大。因此,在高强螺栓连接的设计中,应对螺栓群受力是否进入非线性进行判断,以确定各排螺栓的实际传力比。

In order to solve the problem of bolt missing of the frictional high strength bolted connections（FHSBC） in steel truss bridges,the nonlinear finite element analysis on FHSBC with and without missed bolts was conducted using software ANSYS.In the finite element model,the plates were simulated with a shell element,and the interaction between the splice and core plates at the position of each bolt was simulated with a spring element.The results show that,once the slippage happens in the FHSBC,the correlation between the external load and the transferred shear load of each bolt is nonlinear.The transferred shear loads of bolts without slippage are larger for the outer bolts and smaller for the inner bolts both along the loading direction and the vertical direction,and after part of bolts slips,the non-uniformity decreases.With the number of missing bolts increases,the initial slipping load,the ultimate slipping load and the load transfer ratio of the row of missing bolts all decrease.If no slippage happens or only some bolt slips,the load transfer ratio of the neighboring row has the largest increase; if all the bolts slips,the increase of the load transfer ratioof the rest rows will be the same.In the design of the FHSBC,it should be decided whether the correlation between the load and the transferred load of each bolt is nonlinear,so that a correct load transfer ratio could be obtained.