Abstract:
In this study, several layers of SMA disc springs were arranged in parallel to form a disc spring group, and then gaskets were added between the spring groups, which were then arranged in series to form a disc spring series in order to provide higher bearing capacity and deformation capacity. The finite element software ABAQUS was used to establish a series of 3D refined finite element models of SMA disc spring series, and nonlinear cyclic compression analyses were carried out. The results show that compared with the triangular load-displacement curve of steel disc springs, the load-displacement curve of SMA disc spring series presents a distinct flag shape with obvious forward and reverse transition platform. With the increase of the number of spring groups, the total recoverable deformation of the disc spring series increases, and the ultimate bearing capacity remains unchanged. The secant stiffness decreases with the increase of the number of disc springs, and the total recoverable deformation remains unchanged. Therefore, the number and arrangement of disc springs and disc spring groups can be flexibly adjusted according to the required total ultimate bearing capacity and deformation capacity of disc spring series. Due to the difference in boundary conditions, the stress distribution in different layers of disc springs in a groups is obviously different, and the deformation also presents a dumbbell distribution pattern with higher deformation at the ends and smaller deformation in the middle. The loading end of the disc spring series has the largest deformation, and an overturn failure may occur if it exceeds the deformation limit of the disc spring, which is worth noting. Secondly, a simplified model was proposed for SMA disc spring series. Through nonlinear cyclic compression analyses, it is found that the load-displacement curve of the simplified model is in good agreement with the refined model, while the computational efficiency is improved by about 38 times. A self-centering steel beam-column connection was proposed adopting the SMA disc spring series, and verifying cyclic analysis was conducted on the self-centering steel frame. The results show that the self-centering steel frame with SMA disc spring series can completely return to the original position under a maximum lateral drift of 4%, and the secondary stiffness and ultimate bearing capacity of the self-centering steel frame with SMA disc spring series are nearly 100% and 70% higher than the traditional self-centering steel frame with steel strand.