考虑摩阻效应的大行程滑移支座非线性耦合分析

Nonlinear coupling analysis considering dynamic and static friction effect for large travel sliding bearing

为解决大跨结构支座类构件在其接触面发生特大相对滑移情况下的边界非线性与结构整体几何非线性耦合效应分析问题,基于平面杆系结构有限元分析理论,提出适用于考虑动、静摩阻力的大行程滑移支座全过程受力及变形特性非线性解决方法。完善可精确考虑轴力、弯矩耦合效应的基于随动坐标系下总体拉格朗日列式(CR-TL)的全量梁柱理论,使其适用于一般结构大位移条件下的快速几何非线性分析;采用双单元模式建立滑移支座非线性计算模型,优化适合动、静摩擦因数的滑动-停止判别条件;利用动态单元法、动态刚臂单元法及修正的主从节点法考虑大行程滑移支座滑动模拟过程中的支座斜置现象;建立符合支座滑动全过程受力特性的梁柱理论计算模式,并提出与之相适应的求解非线性方程的变刚度法,以及适应多支座体系协同工作模式的内部折减系数法。研究结果表明:利用CR-TL全量梁柱理论进行大跨斜拉桥结构施工全过程分析时,在相同计算精度水平下,其计算效率可提高30%;当采用不同支座模拟方式时,完全滑动及带摩阻力滑动条件下的单支座与双支座刚架结构位移计算结果相差可达44%~55%;在车辆荷载作用下,大跨斜拉桥结构主梁纵向位移及索塔偏位差达到10cm级别,显著改变了结构的响应特征,提出的理论能够实现对同类工程问题的精细分析。

In order to solve the analysis problem of coupling effect between boundary nonlinearityand geometrical nonlinearity on bearing component of long-span structure where an especially big relative slipping occurs in contact surface, a nonlinear solution in the whole process of mechanical characteristics considering the dynamic and static friction effect in large travel sliding bearing was created based on the finite element analysis theory of plane skeletal structures. The total deformation beam-column theory based on total Lagrange formulation under co-rotating coordinate system （CR-TL） about coupling effect between axial force and bending moment was perfected firstly to make it suitable for rapid geometrically nonlinear analysis on large displacement of general structure. A double element nonlinear calculation model of sliding bearing was built and the criterion condition of sliding-stopping which was suitable for dynamic and static friction coefficient was optimized. The dynamic element method, dynamic rigid arm method, and the modified main and subordinate node method were all used to solve the bearing sideling phenomenon in large travel sliding bearing. A beam-column theory calculation model in the whole process of mechanical characteristics was built, and variable stiffness method for solving the nonlinear equation was put forward. A collaborative work pattern based on internal discount coefficient method which adapted to the multiple bearing element system was applied to calculation. The results show that under the same precision level, the calculation efficiency can be improved by 30% when using CR-TL total deformation beam-column theory to analyze the whole construction process of large span cable-stayed bridge. When using different bearing simulation modes, the result difference between single and double bearing rigid frame under the conditions of absolute slippery and frictional slippery can reach 44% to 55%. Under vehicle load, differences of longitudinal displacement of girder and deviation of pylon can reach to 10 cm level, which significantly changes the response characteristics of structures. The theory can be applied to precise analysis for the same kind of engineering problems. 4 tabs, 9 figs, 26 refs.