Global Analysis Of Beam-Columns System

This paper primarily includes following several parts of research: â‘ . 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. â‘¡. 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. â‘¢. 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.