开口薄壁柱弯扭屈曲时的Wagner效应问题研究

Wagner effect in flexural-torsional buckling of open-profile thin-walled columns

针对弯扭屈曲这种空间失稳形式,基于囊括“平面弯曲理论”和“约束扭转理论”的“泛义弯曲理论”,揭示出薄壁构件弯扭屈曲时的三维空间变形可简化为绕转动中心轴转动的本质;并从双力矩的概念出发,澄清了Wagner效应及系数的概念,即Wagner效应实质上是构件变形时横截面上的正应力所产生的附加双力矩效应,相应地,Wagner系数就是单位变形时横截面上产生的双力矩;提出利用图乘法计算Wagner系数的新思路;按照新方法对开口三板型截面薄壁柱进行计算,从计算结果中揭示出Wagner效应的诸多力学特性及工程应用价值.

In view of the flexural-torsional buckling, one form of spatial instability, and based on the General Bending Theory which combines the Plane Bending Theory and the Bounded Torsion Theory, this paper present the principle that the three-dimensional deformation in flexural-torsional buckling can be simplified to the rotation of cross-section around the rotation-centre-axial. Based on the conception of bimoment, the notion of Wagner effect and coefficient is rectified, i.e. Wagner effect is essentially the additional bimoment effect caused by the normal stress in the deformed cross-section, and accordingly, Wagner coefficient is the bimoment on the cross-section with unit-deformation. Moreover, that the new method calculating Wagner coefficient by graph multiplication is put forward. With the new method, Wagner coefficients of thin-walled 3-plate-type open-profile columns are calculated. From the result data, many mechanics characters and applied value in engineering of Wagner effect are discovered.