## 5 Conclusions  
A series of numerical simulations were conducted in this work, and the nodes' deformation characteristics were studied in the driven mode under different compression rates and rotational speeds, for a forest harvester roller filled with DVWH. The variation characteristics of equivalent stress and radial displacement of nodes were obtained. This work focused on the influence of compression rate and rotational speed on the equivalent stress and radial displacement of nodes near the loading side cell element. The following conclusions can be drawn:  
1. The numerical results indicated that the closer the node was to the loading side, the greater the equivalent stress and radial displacement. In the outermost cell element that made direct contact with the loading plate, the equivalent stress and radial displacement of \(\rm D_{e}\) node were higher than those of the \(\rm A_{e}\) node and Be node, with \(\rm D_{e}\)'s peak equivalent stress being 21.9% and 30.6% higher than \(\rm A_{e}\)'s and \(\rm B_{e}\)'s. In addition, its significant changes were concentrated in passing through the loading plate on the left and right sides of the cell column; that is, the roller rotates between 115\({}^{\circ}\) and 242.6\({}^{\circ}\). In the short time before making contact with the loading plate, the load on the node is the highest. 2. Due to the different loading positions, the outermost cells' deformation characteristics of the roller DVWH structure were different from those of the inner layer. The deformation characteristics of the former were related to the contact state of the loading plate and can be divided into three stages based on the equivalent stress curve characteristics: before contact, during contact, and after contact. The curve of the latter cannot reflect the boundaries of the above states. 3. Within the experimental range, the deformation characteristics of nodes were sensitive to compression rate, and the equivalent stress and radial displacement of nodes were positively correlated with compression rate. Taking De nodes as an example, at a 10% compression rate, their maximum changes in radial displacement were 14.93 mm, and the equivalent stress peak was 111.9 MPa. At a 15% compression rate, their maximum changes in radial displacement were 17.2 mm, and the equivalent stress peak was  
Figure 17: Overall EF of cell column I under different linear speeds (100 mm/s–320 mm/s) and compression ratios (10–15%). 230.9 MPa. The deformation characteristics of nodes were less sensitive to rotational speed. The radial displacement curves of A\({}_{\text{e}}\) and D\({}_{\text{e}}\) nodes with different rotational speeds only had differentiation in the range of 200\({}^{\circ}\)-225\({}^{\circ}\), while the radial displacement curves of B\({}_{\text{e}}\) nodes with different rotational speeds only had differentiation in the range of 137.5\({}^{\circ}\)-156\({}^{\circ}\). 4. At different compression rates, the radial displacement of nodes had different sensitivity to the degree of compression. Overall, the higher the compression rate, the less sensitive the radial displacement of nodes. At a compression rate of 10%, the radial displacement-compression sensitivities of A\({}_{\text{e}}\), B\({}_{\text{e}}\), and D\({}_{\text{e}}\) nodes are 1.294, 1.287, and 0.927, respectively. At a compression rate of 15%, the radial displacement-compression sensitivities of A\({}_{\text{e}}\), B\({}_{\text{e}}\), and D\({}_{\text{e}}\) nodes are 1.228, 1.096, and 0.717, respectively. 5. The compression rate impacted the deformation characteristics of nodes in the time domain, and an increase in compression rate would cause the moment when the node produces the maximum radial displacement to shift back, with a range of 1\({}^{\circ}\) to 3\({}^{\circ}\). 6. For the DVWH under the uniform driven mode, the energy absorption characteristics per unit area and per unit time reflected by the index feed performance efficiency (EF) positively correlate with the speed and compression rate.