均布荷载作用下槽钢绕弱轴的非线性弯曲

Nonlinear bending of channel-section beams about minor axis under uniformly distributed loading

主要通过能量法研究了有限长的简支槽钢梁绕弱轴的弯曲响应,其中的基本假设是受均布荷载作用的薄壁钢梁的总应变能分析可以简化为两个阶段,第一个阶段是腹板和翼缘的局部弯曲响应(板的行为),第二个阶段是截面扁化变形后薄壁钢梁的整体弯曲响应(梁的行为).通过最小势能原理推导均布荷载作用下槽钢梁非线性失稳的理论解,同时还研究了腹板中部增设纵向加劲肋对槽钢梁的非线性弯曲响应的影响.并运用ANSYS对不同尺寸槽钢梁进行了几何非线性分析,结果显示理论解和有限元解之间能够很好的吻合.利用Simitses的方法研究了受冲击均布荷载作用的简支槽钢梁绕弱轴弯曲的动力失稳,讨论了跨度对槽钢梁临界弯矩和非线性弯曲响应的影响.

The bending response of simply-supported channel-section beams of finite length about the minor axis is studied using energy methods.The basic assumption used in the paper is that the analysis of the total strain energy of a channel-section beam subjected to uniformly distributed loading is simplified by a two-stage process：the local bending of the web and flange as a plate and the overall bending of the beam with a deformed cross section as a beam.A theoretical solution for the nonlinear bending of channel-section beams with and without longitudinal stiffeners subjected to uniformly distributed loading is derived using the minimum potential energy principle.To validate the derived theoretical solution,a geometric nonlinear finite element analysis is conducted.A good agreement is shown between the present solution and the FEA results.Finally,the dynamic instability of channel-section beams subjected to sudden step uniformly distributed loading is determined using the Simitses method.The effect of the beam length on the nonlinear bending response and critical bending moment of channel-section beams is discussed.