Dynamic Response Analysis For A Type Of Frame With Mortise And Tenon Joints

In the traditional design concept of steel frame, the node is usually considered to be either fully rigid or pinned entirely. But in some case, semi-rigid connection may be more in line with real project. In fact, any kind of connection is semi-rigid, either fully rigid or pinned do not exist.Therefore, the semi-rigid node of mortise and tenon joints is revealed for the connections between bars. The moment-rotation curve of the semi-rigid node is very complex,considering the friction coefficient and size of the tenons and their mouths. In this paper, a semi-rigid model of mortise and tenon joints is set up. The constitutive relationship of node is indicated by the moment-rotation curve of broken line type.In this theses, the two-storey and one-span scale aluminum space frame model connected by the mortise and tenon joints was established, and the ANSYS finite element analysis software was applied to do dynamic analysis. First of all, the natural frequency of the structure was affected by the initial rotational stiffness of mortise and tenon joint and floor dead weight through modal analysis. Then, the dynamic time-history analysis of the structure was conducted under frequent seismic action and rare earthquake action. According to the influence of the initial rotational stiffness, the intensity of earthquake wave and slab deadweight on the displacement, the acceleration and the stress of column was analyzed. The result shows that the natural frequency of the structure will increase when the initial rotational stiffness rises and will decrease when the slab deadweight reduces. The node is still in the stage of initial rotation stiffness in the case of inputting the seismic action. The displacement and the acceleration of structure reduces along with the increase of the initial rotational stiffness, but the column stress decreases. The displacement and acceleration of structure in the X direction are greater than in the Y direction, on the contrary, the stress of column is less. The displacement, the acceleration and the stress of column increase with rising of the intensity of earthquake wave in the two directions.At last, by comparing the simulation results with the shaking table test results, it is found that there are certain error about the dynamic response, but the change trend basically tallies, which has proved the feasibility of model simulation and analysis method.