# Comparative Analysis of CFRP and Steel Vibration Characteristics of Machine Tools Components
## 3 Results and Discussion
### Chuck Adapter Vibration Experiment
#### 3.2.2 Fastening Part Vibration Characteristics  
The vibration value of the fastening part was measured to determine that of the chuck adapter. The sensor was attached to the fastening part and the measured data were stored on a computer. The rotational speeds of the three types of chuck adapters were synchronized to the output of the controller. The chuck adapter was operated for 30 s, and the vibration velocity and displacement for each of the three kinds of chuck adapter were obtained. The time-domain signals were transformed using the FFT method to evaluate the vibration performance of the CFRP chuck adapter accurately. The vibration velocity at each rotational speed was analyzed in the frequency domain near the rotation frequency of the chuck adapter; that is, only the rotation vibration of the chuck adapter was considered.  
The results are shown in Table 9. The vibration velocity of the fastening part increases as the rotational speed increases. The vibration velocity for the CFRP chuck adapter increased by 17%, the steel chuck adapter by 37%, and the steel chuck adapter by 5%. The displacement increased by 6.7% at 1000 rpm and the maximum performance improvement rate of displacement was 9% at 500 rpm on the fastening part. The minimum of performance improvement rate of displacement was 12% at 10 rpm, and the maximum rate of displacement was 64% at 500 rpm on the fastening part.  
Table 10 shows displacement due to vibration measurement. The displacement for the CFRP chuck adapter increased by 79%, the steel chuck adapter by 108%, and the steel chuck adapter by 40%. The vibration velocity and displacement of the CFRP chuck adapter were the lowest at all rotational speeds. The minimum and maximum performance improvement rates of the vibration velocity for the fastening part were 12.5% and 31.1%, at 500 rpm and 1000 rpm, respectively. Figure 10 shows the performance improvement rate of the CFRP chuck adapter compared to steel in the bearing part. Overall, the CFRP chuck adapter has better or similar displacement than the conventional steel chuck adapter in the fastening part.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Rotating Speed** & \multicolumn{3}{c}{**Displacement (\(\mu\)m)**} & \multicolumn{1}{c}{**Performance**} \\
**(rpm)** & **CFRP** & **Steel** & **CFRP with Steel** & **Improvement (\%)** \\ \hline
10 & 7.381 & 8.336 & 11.423 & 14.2 \\ \hline
500 & 8.588 & 9.796 & 13.467 & 12.5 \\ \hline
1000 & 13.251 & 17.366 & 15.999 & 31.1 \\ \hline \hline \end{tabular}
\end{table}
Table 10: Displacement of fastening part.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Rotating Speed** & \multicolumn{3}{c}{**Vibration Velocity (mm/s)**} & \multicolumn{1}{c}{**Performance**} \\
**(rpm)** & **CFRP** & **Steel** & **CFRP with Steel** & **Improvement (\%)** \\ \hline
10 & 0.146 & 0.164 & 0.2 & 12 \\ \hline
500 & 0.098 & 0.161 & 0.237 & 64 \\ \hline
1000 & 0.172 & 0.229 & 0.217 & 33.4 \\ \hline \hline \end{tabular}
\end{table}
Table 9: Vibration velocity of fastening part.