Experimental Research On Hysteretic Behavior Of Y-Type Chs-Rhs Joint Under Axial Loading

Today, steel tubular structures have been widely used in architectural structures by virtue of their many advantages, such as beautiful appearance, reasonable mechanical behavior and less expense. The mechanical properties about steel tubular joints have been studied in Europe and America since 50's of last century. Until now researches about their static behavior are very mature. However, as a result of a late beginning, there is little of study being done to explore hysteretic behavior of joints under cyclic axial loading. On this basis, the author designed an experiment about CR joints of Y-type in this paper, with the hope of exploring their hysteretic behavior.There are two methods of research in this paper, including test method and FEA method. Firstly, a modal joint was chosen to construct an ANSYS model. According to the change of related parameters, the factors important to joints property and their influence laws were found. Secondly, based on the analysis result, ten specimens were designed and fabricated for the experiment. The parameters of specimens which were explored included the angle between chord and branchθ, width to thickness ratio of main memberγ, diameter to width ratioβ. In this experiment, failure mode of each specimen was observed and recorded, and some analysis was also given to explain the phenomenon occurring during the test process. The sameness and difference of failure modes was summeried to joints with different parameter values. After the experiment, according to analysis of several factors, such as load-carrying capacity, ductility factor, energy dissipation factor, secant stiffness, and hysteretic curve, skeleton curve, the author gave a quantified evaluation about energy dissipation capacity of Y-type CR joints under cyclic axial loading. At last, precise ANSYS models were constructed to all specimens, in order to simulate the whole process of joints experiment from loading to joint's failure. Analysis was given on the development course of modal joint's deformation and stress. During simulating, different views and suggestions were also given to solve the problem about accuracy of FEM. According to the result of comparison, it was found that the simulation method is very accurate at the beginning, but has a serious deviation after the cracks appeared.