# Experimental Investigation on the Mechanical Properties of Curved Metallic Plate Dampers
## 4 Conclusions  
In this paper, four groups of curved plate dampers were selected for theoretical analysis and mechanical properties testing. The main conclusions are as follows:  
1. No visible cracks were found in the dampers during standard loading and fatigue loading, and no obvious damage was observed. The hysteretic curves of standard loading and fatigue loading were very full. In standard loading, each target displacement cycle had three cycles, and the three curves coincided. After 30 cycles of the fatigue cycle, the attenuation of the load index was less than 15%, which indicates that the damper had stable performance. It can be seen from the ductility and energy dissipation coefficient that the four dampers have good deformation and energy dissipation performance. 2. Through stress analysis, the strain at the top of the semi-circular arc was much smaller than that of the end of the semi-circular arc, which shows that for curved plate dampers, the plastic deformation at the end of the semi-circular arc was large, the stress was also large, and the strain change rate was also large. 3. The finite element model was established to simulate the loading process of the specimens. Compared with the hysteretic curves obtained in the test, it was found that the two curves were basically the same except for the individual specimens. Because there are many influencing factors in the testing process, the positive and negative hysteretic asymmetry of the test curve will occur when the small displacement is loaded. In case of the large displacement, the hysteretic area of the finite element analysis curve is slightly larger. The mechanical properties of the damper can be obtained through experiments, finite element simulations, and theoretical calculations. It is reasonable to obtain a coefficient beta of 1.78 by numerical and theoretical computations. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Items** & **CSPD-1** & **CSPD-3** & **CSPD-4** & **CSPD-6** \\ \hline \multirow{3}{*}{Test result} & Yield displacement (mm) & 4.37 & 2.66 & 1.86 & 4.52 \\  & Yield bearing capacity (kN) & 8.78 & 25.42 & 12.53 & 6.97 \\  & Elastic stiffness (kN/mm) & 1.92 & 9.56 & 6.74 & 1.54 \\ \hline \multirow{3}{*}{\
\begin{tabular}{c} Finite element \\ simulation \\ \end{tabular} } & Yield displacement (mm) & 4.18 & 2.44 & 1.82 & 4.20 \\  & Yield bearing capacity (kN) & 9.34 & 27.11 & 14.04 & 7.56 \\  & Elastic stiffness (kN/mm) & 2.13 & 10.11 & 7.71 & 1.80 \\ \hline \multirow{3}{*}{
\begin{tabular}{c} Theoretical \\ calculation \\ \end{tabular} } & Yield displacement (mm) & 2.48\(\beta\) & 1.40\(\beta\) & 1.04\(\beta\) & 2.47\(\beta\) \\  & Yield bearing capacity (kN) & 5.00\(\beta\) & 14.37\(\beta\) & 7.76\(\beta\) & 4.05\(\beta\) \\  & Elastic stiffness (kN/mm) & 2.02 & 10.23 & 7.43 & 1.64 \\ \hline \multirow{3}{*}{Maximum error} & Yield displacement (mm) & 5.50\(\psi\) & 9.02\(\psi\) & 2.20\(\psi\) & 7.62\(\psi\) \\  & Yield bearing capacity (kN) & 6.38\(\psi\) & 6.65\(\psi\) & 10.75\(\psi\) & 7.80\(\psi\) \\  & Elastic stiffness (kN/mm) & 9.86\(\psi\) & 7.01\(\psi\) & 12.58\(\psi\) & 14.44\(\psi\) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Comparison of mechanical properties of curved plate dampers. The maximum error was within the allowable range. At the same time, the correctness of the finite element model and the theoretical formulae was proved. In conclusion, the curved plate damper had the characteristics of a simple structure, clear mechanical performance, and good stability. Conceptualization, J.Z., A.L. and C.Z. ; methodology, J.Z. ; software, J.Z. ; formal analysis, J.Z. ; writing--original draft preparation, J.Z. ; Writing--review and editing, C.Z. All authors have read and agreed to the published version of the manuscript. The research was financially supported by the Ministry of Science and Technology of China (Grant No. 2017 YFC0703603), the National Natural Science Foundation of China (Grant No. 51678322), the Qingdao postdoctoral application research project (Grant No.