## 4 Discussion
In order to study the effect of the compression rate on the radial displacement of nodes, radial displacement-compression sensitivity is proposed:  
\[\eta=\frac{\Delta R}{d} \tag{7}\]  
The ratio of the maximum radial displacement amplitude to the actual compression amount is used to evaluate the sensitivity of nodes' radial position changes to the loading plate's compression behavior in the feed mode. Figure 13: Work by the equivalent stress in the direction of rotation at \(\rm A_{e}\) and \(\rm B_{e}\) points in stages I, II, and III under different compression rates at a line speed of 320 mm/s: (**a**) \(\rm A_{e}\) and (**b**) \(\rm B_{e}\). Figure 14 shows the A\({}_{\rm e}\) node's maximum radial displacement amplitude and radial displacement-compression sensitivity variation under different compression rates at a linear speed of 320 mm/s. It can be seen that within the experimental range, the value of \(\eta\) was the highest at a compression rate of 11%, with a slight change in the compression rate range of 10% to 13% and the highest change in the compression rate range of 13% to 14%. The overall trend of \(\eta\) changes decreased as the compression rate increased. The B\({}_{\rm e}\) node also experienced displacement toward the outside of the roller during stage III, which occurred after cell column 1 left the loading plate. Figure 15 shows node B\({}_{\rm e}\)'s maximum radial displacement amplitude and radial displacement-compression sensitivity under different compression rates (10-15%) at a linear velocity of 320 mm/s. It can be seen that within the experimental range, the maximum radial displacement of the B\({}_{\rm e}\) node during one revolution of the roller showed a decreasing trend. When the compression ratio was 12% and 13%, the radial displacement sensitivity of node B\({}_{\rm e}\) suddenly decreased, and the sensitivity also showed a decreasing trend as the compression ratio increased. Figure 14: Radial displacement-compression sensitivity of A\({}_{\rm e}\) node at different compression rates at a line speed of 320 mm/s. Figure 15: Radial displacement-compression sensitivity of B\({}_{\rm e}\) point at different compression rates at a line speed of 320 mm/s. Figure 16 shows the radial displacement-compression sensitivity of node \(\rm D_{e}\) at different compression rates (10-15%) at a linear speed of 320 mm/s, as well as the rotation angle of the roller when reaching the maximum and minimum radial displacement. At a compression rate of 10%, the moment when the \(\rm D_{e}\) node reached its maximum and minimum radial displacement was 134.42\({}^{\circ}\) and 180.74\({}^{\circ}\), respectively. As the compression rate increased, the moment when it reached its maximum and minimum radial displacement gradually moved back. At a compression rate of 15%, the above moments were 139.06\({}^{\circ}\) and 189.19\({}^{\circ}\), respectively. The difference in the moments when a node reaches its maximum and minimum radial displacement indicates that the compression rate affects the circumferential deformation of the cell. Since the rotation of the roller starts from the axis and transmits torque outwards, within the experimental range, the larger the compression rate, the greater the circumferential displacement of the cells in different layers after rotation, and the farther away from the axis, the greater the circumferential displacement. Figure 17 shows the overall EF of cell column I under the experimental conditions of all the parameter combinations. It can be seen that whether grouped under a fixed speed or a fixed compression rate, the change in EF is positively correlated with speed and compression rate. As the compression rate increases, the growth of EF slows down, with its growth rate decreasing from 12.7% to 8.3%. The growth rate of EF with increasing speed is about 44%, indicating that the change in EF at a speed increment of 44 mm/s in the experiment is more significant than the change in compression rate by 1%.