Mechanics Characteristics of Feeding Roller Filled with Honeycomb Structure of Forest Combine Harvester

Wang Dong;Wang Dian;Liu Jinghao;Huang Qingqing;Beijing Forestry University;

Harvester;;Feeding roll;;Forest engineering;;Damage to logs;;In-plane elastic constants

Aiming at the problem of serious damage to logs caused by the small contact area between the feeding roll and logs when feeding roll locates logs and drives logs to accelerate start or slow down in the machine head during the operation process of forest combine harvester, a double V-winged negative Poisson's ratio(NPR) honeycomb structure was proposed to change the stiffness of the feeding roll and increase the effective contact area between the feeding roll and the logs, thereby reducing the damage to the log. By the displacement method, the theoretical model of the elastic constants in the Y-direction and X-direction plane was established by analyzing the characteristics of double V-winged NPR honeycomb structure, and the solid models with different structural parameters were constructed, and the cell experimental components of the structure were prepared. The effects of thickness t, lower angle θ_1, upper angle θ_2 and cell half-width l on the in-plane elastic constants are studied by finite element simulation and test. The results show that E_y, the Y-direction equivalent modulus of elasticity about the honeycomb, increased with the cell thickness of honeycomb walls, and decreased with the lower angle and half width of honeycomb, and the upper angle had less influence on it. E_x, the X-direction equivalent modulus of elasticity about the honeycomb, increased with the lower angle, upper angle and cell thickness of honeycomb walls, and decreased with the half width of honeycomb, while, the Poisson's ratio ν_(xy) and ν_(yx) are only affected by lower angle and upper angle, but the same parameter had opposite effect on ν_(xy) and ν_(yx). Simulating the vertical pressure on the working head of LAKO 43 HD harvester, when t are 4 and 5 mm, lower angles are 30° and 35°, upper angles are 70° and 75°, and the half width(l) are 29 and 31 mm, the compression of the feeding roll with double V-winged NPR honeycomb structure reaches 10%-30% of the original feeding roll, respectively, which can effectively reduce the damage of the feed roll to the log. It has a certain guiding significance to select the parameters of the feeding roller when adopting the double V-eared negative Poisson's ratio honeycomb structure.