Shear Lag Effect Research And Simplified Analysis Of The Tube Structures

Since the first framed-tube building was designed by Fazlur Khan in 1964, tube structure is widely used in tall building. However, there is an especial feature of tube structure action on horizontal load--Shear Lag Effect. Then, the unitary special strength is falling. Problems come when building is much higher. Tube structure analysis attracts scholars. The classic banding theory is invalid. It is significant in tube structure analysis. The research about shear lag effect has last for dozens of years. However, there are few documents of the causation can be found. It can not be correctly solved until we find the real causation. So, the causation of shear lag effect will be detailedly researched in this article.Simplified analysis is applied in structural project and primary design. It is important to direct porject design when considering shear lag effect. So, the simplified analysis considering shear lag effect will be improved in this article. Continuous model will be used in this paper. According to the space thin-walled structures theory, the unified displacement field of the tube structures is given by taking the shear lag effect into account. Then, the differential equation system which has generality is established by the variational energy method. The solution of the differential equation system is solved by using matrix notations.The main points of this paper are as follows:â‘ Finite element analysis software ANSYS is used to analyze and compare the shear lag effect of the tube structure with variable sections action on horizontal load.â‘¡Expatiate the process of shear lag effect, and find the primary factor of its causation. Give suggestion to the structure design.â‘¢Improve the simplified analysis of the tube considering shear lag effect: Choose new generalized displacement function. Give the unified displacement field of the tube structures. Then, the differential equation system which has generality is established by the variational energy method. The matrix coefficients is given by discrete method when using matrix notations. Solve the differential equation system and compare the results with those calculated by finite element analysis software ANSYS.