# Experiment and Analysis on Friction Damage and Energy Loss Characteristics of Potatoes
## 3 Results and Discussion
### Single Factor Test Results and Discussion
#### 3.2.1 Effect of Initial Height on Friction Damage and Energy Loss of Potato  
The relationship curves for the proportion of epidermal damage and energy consumption loss ratio with initial height are shown in Figure 5. It can be seen from Figure 5 that both the proportion of epidermal damage and the energy consumption loss ratio increase with the initial height. The main reason is that, with the increase in initial height, the gravitational potential energy of potato increases, which causes more kinetic energy of the potato to convert when it reaches the lowest point, thus increasing the proportion of epidermal damage and energy loss at the moment of friction.  
[PERSON] found in a drop test of fragrant pear that the damage area of fragrant pear increases linearly with the increase in drop height [28]. [PERSON] conducted rigid-soft body collision damage test on fresh potatoes and concluded that the damage depth increases with fall height [29]. [PERSON] concluded through a drop impact damage characteristic test of sweet potato that the damage area increased with the initial height [30]. These findings are consistent with the results obtained in this experiment and also show that the initial height is critical for studying the damage characteristics in potatoes. The linear regression equations between initial height and the proportion of epidermal damage as well as the energy consumption loss ratio are shown in Figure 5, with correlation coefficients R2 of  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Test**} & \multicolumn{5}{c}{**Factors and Levels**} \\ \cline{2-6}  & \begin{tabular}{c} **Initial** \\ **Height (mm)** \\ **\(X_{1}\)** \\ \end{tabular} & \begin{tabular}{c} **Potato Mass** \\ **(g)** \(X_{2}\) \\ \end{tabular} & \begin{tabular}{c} **Potato** \\ **Varieties** \\ **\(X_{3}\)** \\ \end{tabular} & \
\begin{tabular}{c} **Friction** \\ **Material** \\ **X4** \\ \end{tabular} &
\begin{tabular}{c} **Temperature** \\ **(°C)** \(X_{5}\) \\ \end{tabular} \\ \hline
1 & 300 & & & & \\
2 & 400 & & & & \\
3 & 500 & 350 \(\pm\) 5 & Xisen 1 & Potato & 22 \(\pm\) 1 \\
4 & 600 & & & & \\
5 & 700 & & & & \\ \hline
6 & & & 150 \(\pm\) 5 & & \\
7 & & 250 \(\pm\) 5 & & & \\
8 & 500 & 350 \(\pm\) 5 & Xisen 1 & Potato & 22 \(\pm\) 1 \\
9 & & 450 \(\pm\) 5 & & & \\
10 & & 550 \(\pm\) 5 & & & \\ \hline
11 & & & & Xisen 6 & \\
12 & & & & Netherlands 15 & \\
13 & 500 & 350 \(\pm\) 5 & Jizhang 12 & Potato & 22 \(\pm\) 1 \\
14 & & & Xuechuanhong & & \\
15 & & & Xisen 1 & & \\ \hline \hline \end{tabular}
\end{table}
Table 4: Single factor test scheme.  
Figure 5: Relationship between initial height and evaluation indexes. Note: The standard deviation range for the proportion of epidermal damage is 0.1–0.5, and the standard deviation range for the energy loss ratio is 2–6.  
0.9862 and 0.9031, respectively, indicating that initial height is highly correlated with the two indicators.  
In summary, the initial height is particularly important for optimizing the design of potato soil separation devices and conveyor drop heights and their related parameters. Therefore, in order to reduce the epidermal damage of potatoes, the height should be considered closely when designing the relevant structures of potato harvesters and conveyors.