## 2 Materials and Methods
### Test Principle  
Collision represents a prevalent mechanical phenomenon, characterized by a brief duration of the collision process [12], minimal displacement of the colliding objects, considerable velocity alterations, substantial impact force exerted by the colliding entities, and energy dissipation. Consider two objects possessing masses \(m_{1}\) and \(m_{2}\), colliding at velocities \(v_{1}\) and \(v_{2}\), respectively. In accordance with the conservation of momentum principle, the momentum conversion formula during the collision process involving these two objects can be deduced, as demonstrated in Equation (1) [13]:  
\[\left\{ \begin{array}{l}m_{1}v_{1}+m_{2}v_{2}=m_{1}v_{1}^{\prime}+m_{2}v_{2} \\ k=\frac{v_{2}-v_{1}}{v_{1}-v_{2}}\end{array} \right. \tag{1}\] \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Material** & **Size mm** & **Density** & **Young’s Modulus** & **Poisson’s** \\
**Model** & **(Length, Width, Thickness)** & **(g\(\cdot\)cm\({}^{-3}\))** & **(MPa)** & **Ratio** \\ \hline Q235 & & & & \\ Steel & & & & & \\ Rubber & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Collision material properties. After derivation and calculation, velocities \(v_{1}\) and \(v_{2}\) after the collision can be ascertained, as indicated in Equation (2):  
\[\left\{ \begin{array}{l}v_{1}=v_{1}-(1+k)\frac{m_{2}}{m_{1}+m_{2}}(v_{1}-v_{2}) \\ v_{2}=v_{2}+(1+k)\frac{m_{1}}{m_{1}+m_{2}}(v_{1}-v_{2})\end{array} \right. \tag{2}\]  
when \(k\) is equal to 1,  
\[\left\{ \begin{array}{l}v_{1}=v_{1}-\frac{2m_{2}}{m_{1}+m_{2}}(v_{1}-v_{2}) \\ v_{2}^{\prime}=v_{2}+\frac{2m_{1}}{m_{1}+m_{2}}(v_{1}-v_{2})\end{array} \right. \tag{3}\]  
when \(k\) is equal to 0,  
\[v_{1}=v_{2}=\frac{m_{1}v_{1}+m_{2}v_{2}}{m_{1}+m_{2}} \tag{4}\]  
where \(m_{1}\) and \(m_{2}\) denote the masses of the two colliding objects, with the unit in kg. \(v_{1}\) and \(v_{2}\) represent the pre-collision velocities of the two colliding objects, expressed in m/s; and \(v_{1}\) and \(v_{2}\) correspond to the post-collision velocities of the objects, with the unit in m/s. The reference formatting has been adjusted. Upon analyzing Equations (3) and (4), it becomes apparent that the k value dictates the post-collision velocity alteration of the objects. When \(k=1\), a perfect elastic collision transpires, and the velocities of the two objects are transferred. Notably, when \(m_{1}=m_{2}\), the velocities of the two objects are exchanged following the collision. When \(k=0\), an imperfectly elastic collision occurs. Post-collision, the velocities become identical and the two objects proceed in unison. In addition to their velocity, the kinetic energy of the two objects undergoes alteration following the collision, with the most pronounced change being kinetic energy loss. Figure 1: Grain impact test bench. 1. test bed bracket; 2. grain collection plane; 3. collision plate; 4. grain delivery mechanism; 5. grain height lifting screw. Equation (5) illustrates the pre- and post-collision kinetic energy equation, with \(T_{1}\) and \(T_{2}\) representing the cumulative kinetic energy before and after the collision, respectively. \[\left\{ \begin{array}{l}T_{1}=\frac{1}{2}m_{1}v_{1}^{2}+\frac{1}{2}m_{2}v_{2}^{ 2}\\ T_{2}=\frac{1}{2}m_{1}v_{1}^{2}+\frac{1}{2}m_{2}v_{2}^{2}\end{array} \right. \tag{5}\]  
The total kinetic energy loss of the two objects post-collision can be derived, as displayed in Equation (6):  
\[ \begin{array}{l}\triangle T=T_{1}-T_{2}\\ =\frac{m_{1}m_{2}}{2(m_{1}+m_{2})}(1+k)^{2}(v_{1}-v_{2})^{2}\end{array}  \tag{6}\]  
when \(k=1\), kinetic energy loss is expressed as Equation (7):  
\[\triangle T=T_{1}-T_{2}=0 \tag{7}\]  
where \(T_{1}\) signifies the aggregate kinetic energy of the two objects prior to the collision, with the unit in J; \(T_{2}\) represents the total kinetic energy of the two bodies following the collision, with the unit in J; and \(\Delta T\) denotes the difference in kinetic energy between the two objects pre- and post-collision, expressed in J.