## 3 Results and Discussion
### Verification for Experiment and FE Models
[46], and [PERSON] et al. [47]. Moreover, the study of [PERSON] et al. [29] works well for designs of various sizes when the number of nodes is 23,022 and the element size is 4 mm as shown in Table 5.  
The test results showed a slight 0.85% deviation from natural frequencies in modes 1 and 2, which aligned with other studies(in Figure 7). With 23,022 elements, the FE model frequency matched the test results for virgin steel. Insights gained  
Figure 6: The convergence test on the finite element model for tetrahedral elements with mid-side nodes: C3D10M of virgin steel. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Mode 1**} & \multicolumn{3}{c}{**Mode 2**} \\ \cline{2-7}
**The Number** & \multirow{2}{*}{**FEM**} & \multirow{2}{*}{**Exp.**} & **Research** & \multirow{2}{*}{**FEM**} & \multirow{2}{*}{**Exp.**} & **Research** \\
**of Elements** & & & & **Article** & [36; 42] & & **Article** \\ \hline
**16** & 18.882 & \multirow{5}{*}{50.372} & \multirow{5}{*}{51.63} & 58.098 & \multirow{5}{*}{125.2} & \multirow{5}{*}{121.95} \\
**21** & 50.901 & & & 128.23 & & \\
**907** & 50.578 & & & 126.53 & & \\
**6045** & 50.372 & & & 124.88 & & \\
**23,022** & 50.184 & & & 123.98 & & \\
**28,523** & 50.131 & & & 123.71 & & \\
**198,367** & 50.111 & & & 123.59 & & \\
**267,062** & 50.154 & & & 123.99 & & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The national frequency in modes 1 and 2 of hole steel for C3D10M type. From the testing and convergence of natural results, the results can be precise about natural frequencies using sufficient components and more detailed mesh in the nearby area. The models used the tetrahedral elements with mid-side nodes (C3D10M) format [46]. The frequency analysis is performed for examples that do not have different processes and different notches. All three are shown in Figure 8a-c.  
Figure 8: _Cont._  
Figure 7: The convergence test on the finite element model for tetrahedral elements with mid-side nodes: C3D10M of hole steel. The FE model can predict better test results, so the experiment confirms the performance of the natural frequency value. There is a tight seizing of the test of low carbon steel sheet. As depicted in Figure 2b, the experiment setup was monitored using the accelerometer signal from the Arduino Board, Due 2012 R3. The oscilloscope from Keysight Technologies 3000 T was used to test the signal in the workpiece. Both devices could read the signal value, as shown in Figure 9. The results of the Arduino model Due 2012 R3 and the oscilloscope were similar, with an expectation of just a 0.001% difference in calculations. In addition, the force sensor calibration uses the testing machine with the universal testing machine by testing the force between 0 and 122 Newtons testing five times, using a significance of 0.95, which is in line with the research of [PERSON]. [PERSON] et al. [40], and [PERSON] et al. [41] reported the Arduino 2012 R3 that is equivalent to a device that is high priced. The results of the body's movement test and the electric train's movement found that the Arduino model Due 2012 R3 stands the actual test [48]. In the same way, the value that has been analyzed is regression using the R-squared value. When calculated, it is equal to 0.997 when calibrating the accelerometer and force from the force sensor test when  
Figure 8: Meshing the geometry (**a**) virgin sheet metal, (**b**) hole notch, and (**c**) V notch. connecting and working simultaneously. The signal can be captured as shown in Figure 10. The result is in line with the results of the dynamic test of the structure. The research report using the Arduino 2012 R3 shows that Arduino is lower than other systems that are used in comparison and has better accuracy in low frequencies for the amplitude of low-speed acceleration than the final result of the fast Fourier transform (FFT) assessment that shows a better observation resolution for Arduino than the control system as performed in the research of [PERSON] et al. [49] and [PERSON] et al. [50].