# A Novel Ring Spring Vibration Isolator for Metro Superstructure
## 3 Results
### The Design of Vibration Isolator  
This paper proposes a new ring spring vibration isolator (Figure 10) which mainly includes the upper and lower connecting plates, upper pressure plates, connecting screws, lock nuts, and thick-walled ring springs.  
(1) Upper and lower connecting plates are composed of steel plates, where several bolt holes are found. Through the holes, these plates are connected to the column and the foundation by high-strength bolts.  
(2) As for the upper pressure plate, there must be enough spring compression moving space between the upper pressure plate and the upper connecting plate.  
(3) The connection screw is set between the upper pressure plate and the lower connection plate, and it is movable between the two plates. When the spring is under  
Figure 10: Schematic diagram of the structure of a new ring spring isolator.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Type**} & \multirow{2}{*}{**Group**} & \multicolumn{5}{c}{**The Maximum Tensile Stress of Outer Ring (Mpa)**} \\ \cline{3-6}  & & \begin{tabular}{c} **Theoretical** \\ **Value** \\ \end{tabular} & \begin{tabular}{c} **Correction** \\ **Value** \\ \end{tabular} & \begin{tabular}{c} **Simulation** \\ **Value** \\ \end{tabular} & \
\begin{tabular}{c} **Theoretical** \\ **Value** \\ \end{tabular} &
\begin{tabular}{c} **Correction** \\ **Value** \\ \end{tabular} \\ \hline \multirow{4}{*}{Thin-walled} & 1 & 1125 & 995 & 1263 & \(-10.9\%\) & \(-21.2\%\) \\  & 2 & 1035 & 885 & 1045 & \(-1.0\%\) & \(-15.3\%\) \\  & 3 & 961 & 794 & 905 & 6.2\% & \(-12.3\%\) \\  & 4 & 1063 & 851 & 923 & 15.2\% & \(-7.8\%\) \\ \hline \multirow{4}{*}{Thick-walled} & 5 & 1156 & 896 & 966 & 19.7\% & \(-7.2\%\) \\  & 6 & 1328 & 967 & 1035 & 28.3\% & \(-6.6\%\) \\ \cline{1-1}  & 7 & 1584 & 1054 & 1119 & 41.6\% & \(-5.8\%\) \\ \cline{1-1}  & 8 & 1766 & 1109 & 1174 & 50.4\% & \(-5.5\%\) \\ \hline \hline \end{tabular}
\end{table}
Table 3: Comparative analysis of the maximum tensile stress of the outer ring by theoretical calculation and numerical simulation.  
pressure, the vertical load is transmitted to the upper pressure plate through the upper connecting plate. Then, the upper pressure plate compresses the spring and the screw stays still. When the spring is under the tension, the lock nut set on the screw limits the displacement of the spring and prevents its structure from being damaged by the tension. The spring can also be preloaded by connecting the screw and the lock nut.  
(4) A thick-walled ring spring is located between the upper pressure plate and the lower connecting plate. It is composed of several outer rings, several inner rings, and two halves of inner rings. The wall thickness of the ring is 1/10 to 1/20 of the diameter. A rubber film can be placed between the spring and the steel plate to reduce metal wear. The spring isolator can be made up of several thick-walled same-sized spring groups in parallel.  
To meet the requirements of both space constraints and bearing capacity, we can install more than one new ring spring isolator under the column. The barycenter of the new ring spring isolator coincides with the barycenter of the column, so the load of the superstructure can be better transmitted to the vibration isolator.