# Research on Propagation Characteristics of Tire Cavity Resonance Noise in the Automobile Suspension
## 4 Power Flow Analysis of Tire Cavity Resonance Noise Propagation in a Suspension System
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Inflation Pressure Condition**} & \multicolumn{2}{c}{**Sum of Structural Sound Intensity (10\({}^{-3}\) W/mm\({}^{2}\))**} & \multirow{2}{*}{**Number of Points**} & \multirow{2}{*}{\
\begin{tabular}{c} **Cross** \\ **Sectional** \\ **Area (mm\({}^{2}\))** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Power Flow of Cross** \\ **Sectional** \\ **Sectional** \\ **(10\({}^{-3}\) W)** \\ \end{tabular} } \\ \hline \multirow{2}{*}{0.16 MPa} & Input & 2.849 \(\times\) 10\({}^{-2}\) & 15,064 & 81,367 & 1.539 \(\times\) 10\({}^{-1}\) \\  & Output & 2.603 \(\times\) 10\({}^{-4}\) & 2652 & 11,180 & 1.097 \(\times\) 10\({}^{-3}\) \\ \hline \multirow{2}{*}{0.19 MPa} & Input & 2.830 \(\times\) 10\({}^{-2}\) & 15,064 & 81,367 & 1.529 \(\times\) 10\({}^{-1}\) \\  & Output & 2.648 \(\times\) 10\({}^{-4}\) & 2652 & 11,180 & 1.116 \(\times\) 10\({}^{-3}\) \\ \hline \multirow{2}{*}{0.22 MPa} & Input & 2.811 \(\times\) 10\({}^{-2}\) & 15,064 & 81,367 & 1.518 \(\times\) 10\({}^{-1}\) \\  & Output & 2.702 \(\times\) 10\({}^{-4}\) & 2652 & 11,180 & 1.139 \(\times\) 10\({}^{-3}\) \\ \hline \multirow{2}{*}{0.25 MPa} & Input & 2.821 \(\times\) 10\({}^{-2}\) & 15,064 & 81,367 & 1.523 \(\times\) 10\({}^{-1}\) \\  & Output & 2.662 \(\times\) 10\({}^{-4}\) & 2652 & 11,180 & 1.122 \(\times\) 10\({}^{-3}\) \\ \hline \multirow{2}{*}{0.28 MPa} & Input & 2.836 \(\times\) 10\({}^{-2}\) & 15,064 & 81,367 & 1.532 \(\times\) 10\({}^{-1}\) \\  & Output & 2.615 \(\times\) 10\({}^{-4}\) & 2652 & 11,180 & 1.102 \(\times\) 10\({}^{-3}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Simulation results of sum power flow of input and three output sections. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Load Condition**} & \multicolumn{2}{c}{**Sum of Structural Sound Intensity (10\({}^{-3}\) W/mm\({}^{2}\))**} & \multirow{2}{*}{\begin{tabular}{c} **Number of** \\ **Points** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Cross** \\ **Sectional** \\ **Area (mm\({}^{2}\))** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Power Flow** \\ **of Cross** \\ **Sectional** \\ **(10\({}^{-3}\) W)** \\ \end{tabular} } \\ \hline \multirow{2}{*}{2500 N} & Input & 2.831 \(\times\) 10\({}^{-2}\) & 15,064 & 81,367 & 1.529 \(\times\) 10\({}^{-1}\) \\  & Output & 2.793 \(\times\) 10\({}^{-4}\) & 2652 & 11,180 & 1.177 \(\times\) 10\({}^{-3}\) \\ \hline \multirow{2}{*}{3000 N} & Input & 2.867 \(\times\) 10\({}^{-2}\) & 15,064 & 81,367 & 1.549 \(\times\) 10\({}^{-1}\) \\  & Output & 2.627 \(\times\) 10\({}^{-4}\) & 2652 & 11,180 & 1.107 \(\times\) 10\({}^{-3}\) \\ \hline \multirow{2}{*}{3500 N} & Input & 2.848 \(\times\) 10\({}^{-2}\) & 15,064 & 81,367 & 1.538 \(\times\) 10\({}^{-1}\) \\  & Output & 2.503 \(\times\) 10\({}^{-4}\) & 2652 & 11,180 & 1.055 \(\times\) 10\({}^{-3}\) \\ \hline \multirow{2}{*}{4000 N} & Input & 2.897 \(\times\) 10\({}^{-2}\) & 15,064 & 81,367 & 1.565 \(\times\) 10\({}^{-1}\) \\  & Output & 2.402 \(\times\) 10\({}^{-4}\) & 2652 & 11,180 & 1.013 \(\times\) 10\({}^{-3}\) \\ \hline \multirow{2}{*}{4500 N} & Input & 2.975 \(\times\) 10\({}^{-2}\) & 15,064 & 81,367 & 1.607 \(\times\) 10\({}^{-1}\) \\  & Output & 2.290 \(\times\) 10\({}^{-4}\) & 2652 & 11,180 & 9.652 \(\times\) 10\({}^{-4}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Finite element calculation results of total power flow of input and three output sections. of the suspension system was the largest. Under the other four inflation pressures, the output power flow of the suspension system was relatively low. Based on the sound pressure amplitude distribution of the tire cavity resonance noise under different speed conditions with 0.22 MPa inflation pressure and 3000 N load, the power flow results of the input surface and three output surfaces of the suspension system were calculated, as shown in Table 7.  
From Table 7, it can be seen that for the suspension system at different speeds, the total power flow of the three output surfaces was quite different.