【作者】 谢华；

【导师】 李开禧；

【作者基本信息】 重庆大学 ， 结构工程， 2005， 硕士

【摘要】 本文主要做了以下几方面的研究工作: ①.比较完整地讨论了一种考虑二阶效应的位移法,这种位移法在各种情况下都普遍适用。推导出了新的形常数和载常数,不仅考虑了轴向压力的情况,而且还考虑了轴向拉力的情况;还建立了梁柱的单元刚度矩阵;通过例题,说明了这种的位移法的具体运用过程。和传统位移法相比,这种位移法在模式上是完全相同的,继承了传统位移法的优点,是一种适合于计算机进行编程计算的方法。这种位移法能够比较容易地绘出非常精确的考虑二阶效应的总弯矩图,而稳定分析的目标就是绘出总弯矩图。②. 提出了结构的“内力重分配”这个新的概念,其表现主要体现在三个方面:第一个方面是直观的表现,即由于轴向荷载的存在,引起的所在杆件刚度的变化;第二个方面是由于轴向荷载的大小变化,引起的整个结构内力的重新分配;第三个方面是由于结构所受的横向荷载的方向变化,引起的二阶效应对整个结构内力影响的变化。由于其第一方面是众所周知的,所以只是着重举例说明了后两方面的表现,同时也阐述了其对结构设计的重大影响。轴向荷载引起的“内力重分配”是与钢弹塑性引起的内力重分配具有同等重要地位的。③. 还简要提出了另一个新概念——结构的屈曲后强度。举例说明了一下,结构的屈曲后强度的表现;还推导出对于轴向压力,轴向总变形为轴力的影响与弯矩的影响之和的表达式。总的来说,本文全部都是在体现对于结构稳定问题必须对结构进行整体分析这一观点,同时也印证了结构稳定问题是具有整体性和相关性的。由于时间有限,本文还存在着很多不足,如本文提出了这种考虑二阶效应的位移法,只是针对轴向荷载的影响,并没有考虑如初弯曲、残余应力等其它缺陷,也没有引入弹塑性,在空间方面的发展也没有具体说明;在结构的屈曲后强度方面,并没有具体说出其计算的方法。鉴于这些不足,还有待于后续的进一步深入研究。更多还原

【Abstract】 This paper primarily includes following several parts of research: ①. Discuss a new kind of the displacement method that considers second-order effects. This kind of displacement method is universally applied under various conditions. New distortion constants and load constants are deduced in condition of the axial pressure and the axial tension. The unit stiffness matrix of the beam-column is established. Taking an example, we explain specific applying process of this kind of displacement method. The mode of this kind of displacement method is uniform comparing with that of the traditional displacement method. The new displacement method has inherits the advantages of the traditional displacement method. It is a method suited for programming to calculate by computers. The very accurate total bending moment diagram in that the second-order effects are considered can be draw using the new displacement method, and that the aim of stability analysis is to draw the total bending moment diagram. ②. Put forward the new concept of "redistribution of internal force" of the structure. That mainly represent in the following three aspects: The first aspect is intuitionistic representation. Because of the existence of axial load, the stiffness of the member has changed. The second aspect is that the change of axial load leads to redistribution of internal force the internal force of the whole structure. The third aspect is that the direction variety of the lateral load of the structure leads to the change of the influence caused by second-order effects on the internal force of whole structure. Because the first aspect is well-known, in the paper we only give emphasis to illustrate the representations of the latter aspects and also elaborate the important influence to structure design. "Redistribution of internal force" brought by the axial load is in the same important degree as redistribution of internal force brought by the elasticity-plasticity of steel. ③. Briefly put forward another new concept --the strength of structure after buckling. We illustrate the representation of the strength of structure after buckling with examples; deduce the expression of the total axial distortion that is composed of the influence of axial pressure and the influence of bending moment. All in all, in this paper, the viewpoint that stability problems of structure must be carried on global analysis is incarnated and the globality and relativity of stability problems of structure is corroborated. Since the time is limited, this paper has some shortages. For example, the kind of the displacement method considering second-order effects only aims at the influence of axial load. Initially curve, residual stress etc has not been considered. Elasticity-plasticity has not been imported. The development of the space aspect has not been specifically elucidated. The paper does not introduce how to compute the strength of structure after buckling. As for these disadvantages, would be left behind to further research.更多还原