集中荷载作用下一次超静定梁的弹塑性过程改进分析  

The Improved Analysis of the Elastic-Plastic Process of a Beam with One Degree of Indeterminacy under a Concentrated Load

作　　者：李会知[1] 张幸涛[1] 李佳莹[2] 

机构地区：[1]郑州大学土木工程学院,河南郑州450001 [2]西南交通大学土木工程学院,四川成都611756

出　　处：《力学季刊》2013年第4期636-642,共7页Chinese Quarterly of Mechanics

摘　　要：对跨中集中外荷载作用下一次超静定梁的弹塑性加载和变形全过程进行了改进分析.根据受力变形特点,超静定梁的加载过程可分为四个阶段,分别是弹性阶段、固支端附近塑性变形区扩展阶段、固支端附近和集中荷载作用点附近塑性变形区扩展阶段、固支端保持为塑性铰而固支端附近的弹塑性区发生卸载现象但集中荷载作用点附近塑性变形区继续扩展阶段.在弹性阶段,位移与外荷载是线性比例关系,在后三个阶段,位移与外荷载是复杂的非线性关系.针对现有研究中位移计算存在的错误,给出了第四阶段全过程任意点的位移计算公式,给出了跨中位置点各阶段荷载终值对应的位移.给出的位移公式,可供工程结构设计应用.The improved analysis of the elastic-plastic process of loading and deformation of a beam with one degree of indeterminacy under a concentrated load was made. Based on the deformation feature, the up-loading process can be divided into four stages as following： elastic stage, the second stage is that beam region near the fixed end is in plastic propagation state, the third stage is that both beam regions near fixed end and near the point where the concentrated load acts are in propagation plastic state, the fourth stage is that the fixed end behaves as a plastic hinge while the plastic region near the fixed end is unloaded and the plastic region near the mid-point is propagating to the bestraddle. In the elastic stage, the relation between displacement and the load is proportion. In the other stages, the relation between displacement and the load is complicated and nonlinear. For the existing results have some errors in the displacement computing, the formulas of displacement of arbitrary point were derived in the fourth stage and the responding displacement of the mid-point was calculated at each stage. The formulas of displacement can be applied to engineering structure design.

关 键 词：超静定梁 弹塑性 塑性铰 集中荷载 位移 

分 类 号：TU323.3[建筑科学—结构工程]