摘要
开口薄壁构件的翘曲可视为各板件面内弯曲的组合,因此无需确定截面弯心和翘曲惯矩等参数,也能获得构件抗力性能描述;单肢化的假想荷载分析及其结论的灵活综合,可清晰表述弯扭屈曲时复杂的荷载附加效应,并能在结论中自然反映以Wagner效应为代表的诸多复杂因素。基于上述措施,该文所提出的弯扭屈曲分析方法具有简单的推导过程和结论形式,无需引入复杂的板壳非线性分析理论,但解决了Bleich的方法中横向荷载Wagner效应缺失问题以及轴向偏心荷载与横向荷载所致弯矩的附加效应形式不统一的问题,并对多样化的截面构型、荷载类型及约束方式提供广泛适应性。对于各种典型的弹性弯扭屈曲问题,特别是其中目前尚存在广泛争议的单轴对称截面梁的侧向屈曲问题,该方法均取得了良好的对比分析结论。分析表明:把薄壁构件凝聚到轴上进行分析和结论表述这一传统措施造成二阶分析中的诸多困难,并可能导致不易察觉的疏漏,该文的单肢解析化思路有助于避免这些问题。
It is recognized that the resistance modulus of a thin-walled open-profile member can be described without determination of its cross-section＇s shear center as well as the warping modulus or other parameters because the warping can be looked on as a syntheses of its slabs＇ bending, and that the slabs-disassembled analyses of fictitious loads and their flexible integration can explicitly depict the complex additional effects of loads on a flexural-torsional buckled member and hence in the conclusions, embody various complex factors such as the Wagner term. In consequence, without involvement of nonlinear analysis theory of shells, the flexuraltorsional buckling analysis proposed here has solved the problems of the absence of transverse loads＇ Wagner term and the non-uniform additional effects of moments produced by eccentric axial loads and transverse loads in Bleich＇s method. In addition, the proposal here is predicted to be widely applicable to various cross-sections, loads and constraint conditions. The method proposed in this paper has been proved to witness sound contrastive results in its application of various kinds of typical elastic flexural-torsional bucklings, especially in that of the lateral buckling of the monosymmetrical section beam characteristic of wide controversy at present. It is shown in the analysis that the traditional method, in which the thin-walled members are concentrated to their axes, would cause problems in their second-order analyses, and some other unidentifiable omissions. However, the slabs-disassembled method proposed in this paper has been proved helpful in solving such problems.
出处
《工程力学》
EI
CSCD
北大核心
2009年第6期16-20,26,共6页
Engineering Mechanics
关键词
弯扭屈曲
开口薄壁构件
单肢化方法
翘曲理论
稳定
flexural-torsional buckling
thin-walled open-profile members
slabs-disassembled method
warping theory
stability
