薄壁箱梁畸变分析理论的研究

RESEARCH ON DISTORTION ANANLYSIS THEORY OF THIN-WALLED BOX GIRDER

对薄壁箱梁以畸变角和畸变挠度为位移参数的两种畸变理论进行比较分析,证明了两种理论的计算结果是完全一致的。根据箱梁的变位协调关系得出畸变挠度和畸变角的互换性,从而建立了两种理论的控制微分方程的互换方程。采用广义坐标法,明确了畸变中心的定义,确定了畸变位移模式,进而基于能量变分原理,建立了充分考虑剪切变形效应的畸变分析理论,推导了求解的初参数法,研究了剪切变形的影响。结果表明:剪切变形对畸变翘曲应力和横向弯曲应力的影响较小。

Comparison and analysis are performed for two typical theories with distortion angle ana alstortaon deflection as displacement parameters. Their results are proved to be identical. The conversion between distortion deflection and distortion angle is established by use of the displacement coordination of cross-section frame, and the conversion functions for the governing differential equations of both theories are derived. Based on the generalized coordinate principle, an explicit definition is given for the distortion centre and displacement modes are determined, and then an analytical theory is presented using energy variational principle, which sufficiently takes account of shear deformation. The formats of initial parameters are deduced to solve the presented differential equations. The influence of shear deformation is investigated and the results show that shear deformation affect insignificantly the distortion warping stress and transverse bending stress.