摘要
在截面纵向位移模式中,通过引入轴向位移以描述压弯作用下Π形梁的截面变形状态。基于能量变分法导出轴向位移、竖向位移和剪力滞位移之间相互耦合的控制微分方程组,并以通解和边界条件建立节点力与节点位移间的对应关系,从而导出压弯作用下考虑剪力滞的Π形梁单元刚度矩阵。利用ANSYS实体单元和导出的一维Π形梁单元分别对简支梁、悬臂梁和连续梁进行分析,以验证其有效性和可靠性。研究表明,在压弯作用下,由于剪力滞的影响Π形梁的轴向位移沿梁长不再按照直线变化,而随受力状态和边界条件的不同而改变;连续梁中间支座处轴向位移出现跳跃现象,跳跃方向沿轴力反向;Π形梁的剪力滞矩和弯矩有相似的分布规律,但剪力滞矩的绝对值远小于弯矩的绝对值。
In the section longitudinal displacement mode,the axial displacement is introduced to describe the section deformation state of Πshaped girder under axial compression and bending.Based on the variational principle,the governing differential equations coupled with axial displacement,vertical displacement and shearlag displacement are obtained,and the relationship between nodal forces and nodal displacements is established by use of the general solutions and the boundary conditions,to derive the element stiffness matrix of Πshaped girder considering shear lag under axial compression and bending.With ANSYS solid elements and the derived onedimensional Πshaped girder element,simply supported girder,cantilever girder and continuous girder are analyzed to verify its validity and reliability.The results show that the axial displacement of Πshaped girder changes no longer in accordance with the straight line,but varies with the force state and the boundary conditions due to the influence of the shear lag.The axial displacement at the middle support of the continuous girder appears saltation,and the saltation direction is opposite to the axial force.The shear lag moment and the bending moment of Πshaped girder have similar distributions,but the absolute value of shear lag moment is much smaller than that of the bending moment.
作者
周世军
宋刚
ZHOU Shijun;SONG Gang(School of Civil Engineering,Chongqing University,Chongqing 400045,China;Key Laboratory of New Teclinology for Construction of Cities in Mountain Area,Chongqing University,Chongqing 400045,China)
出处
《结构工程师》
北大核心
2018年第6期8-15,共8页
Structural Engineers
关键词
Π形梁
剪力滞
轴向位移
有限梁段法
实体单元
Πshaped girder
shear lag
axial displacement
finite segment method
solid element
