Finite Element Analysis On Static Behavior Of Spatial RHS TT-joints

Tubular structure is used more and more widely in the realm of engineering for its superior behavior and great visual effect. The rectangular hollow section (RHS) structure has its own advantages in compare with the circle hollow section (CHS) structure. The CHS structure need spatial cutting at the intersections, which is a very complicated technologic process. While the RHS structure need only plane cutting, which can simplify the technologic process and reduce the cost. So people throw more and more concern on the RHS structure.In this paper, the author studied on the static behavior of the RHS-joints by nonlinear finite element analysis. After established physical models of the joints, the failure modes and the ultimate load-carrying capacity of the simple T joints and the multiple TT joints are comparatively analyzed. Three parameters were considered, such as the ratio of the branch width to the chord width ( β ), the ratio of the chord width to its thickness ( γ ) and the ratio of the branch thickness to the chord thickness ( τ ), which would probably influence the ultimate load-carrying capacity of the joints. The influence degree of the three factors were studied and through the comparison of the ultimate load-carrying capacity between the T joints and the TT joints, the influence of the out-plane branches done on the joints were obtained.The whole article is divided into five chapters. In chapter one, the types, characteristics, development, application and current study status of the tubular structure are involved. In the second chapter, elastic and plastic theory and the basic theory of finite elements analysis are introduced. In the third chapter, the establishment process of T-joints and TT-joints is given. In the fourth chapter, the author stated the failure models of the joints, the development process of the stress, analyzed the influence of the geometrical parameters, compared the ultimate load carrying capacity between the TT-joints and its according T-joints, got the influence of the load applied on the outer-plane branch. In the last chapter, the above chapters are summarized, some problems deserving further studyingin tubular structure are pointed out. And the prospect of the RHS structure is expected.This article perfects the finite element analysis of the spatial tubular joints, points out the influence factors on the spatial joints. It will do some good to the design in engineering.