简支工字梁在偏心荷载下空间失稳问题的计算

Calculation of the spatial instability problem for the simply supported l-beam under the eccentric loads

在薄壁杆件空间弹性失稳势能的变分方程中 ,应用附加弯矩与扭矩及其所对应的失稳位移的曲率与扭率的增量来表达其外力失稳势能 .该微分方程通过分部积分法应用位移及应力自然边界条件 ,得出各阶微分方程的迦辽金法的方程组来进行计算 ,从而简便解决了偏心荷载下简支工字梁的空间失稳问题 .

In the variation equation of unstable potential energies,the potential energies of external forces by using additional moments of flexure and moments of torsion and their correspondent curvatures of unstable dispacements and increment of torsion angle are represented.Through partial integration method and with the application of displacement and natural boundary condition for stress,we can get all order differential equations form variation equation of potential energy for spatial elastic instability and conveniently resolve the spatial instability problem for the simply supported l beam under the eccentric loads.