开口薄壁杆的板件面内拉弯综合抗力体系

Slabs' In-plane Tension-bending Resistance System of Thin-walled Open-profile

针对薄壁杆件力学分析较为复杂的问题,讨论了一种把开口薄壁杆的分析拆分为2个较简单部分的方法。针对薄壁中面内荷载效应的分析问题,首先在适当简化基本应力应变条件的基础上,按平面应力问题分析单肢板件面内荷载效应,然后对其进行向量综合,得到反映开口薄壁杆轴向伸缩、弯曲及翘曲性质的"板件面内拉弯综合抗力体系"及其变形方程;探讨了刚度方程的建立及其计算特点,并与经典理论进行对比。分析表明,在板件面内弯矩定义中引入板件间纵向相互作用力,可简化该体系分析过程和结论,使之具备与平面弯曲问题一致的形式。作为应用举例,推导了求解薄壁截面主轴方向、主轴惯性矩、弯心坐标、主扇性惯性矩的线性方程组,剖析了经典理论中这些截面几何特性对于计算的意义及其效率。

In order to simplify the analyses of thin-walled open-profile bars, a thin-walled bar was split into two parts which were dominated by in-plane and out-plane loading effects respectively. The in-plane loading effects were focused. On the basis of appropriate simplified stress and strain conditions, each plate was analyzed and the results were integrated into vectors, resulting in the slabs＇ in-plane tension-bending resistance system of thin-walled open-profile bars, which reflects their axial stretch/compression, bending and warping properties. And then the deformation equation and the stiffness equation were set up. Because longitudinal interaction forces between plates were introduced in the definition of the plates＇ in-plane bending moments, the deduction and conclusions here were consistent in form with those in bending theory. Principal axes＇ directions, shear center＇s coordinates, principal inertia moments and sectorial inertia moment of thin-walled open sections can be deduced by the slabs-disassembled method proposed here. Lateral deformed bars＇ analysis based on those sectional parameters in classical theory is proved to be inefficient, where additional ＂rigid contour hypothesis＂ has to be introduced.