Experimental Study on Impact Friction Damage of Sweet Potato Skin

Sweet potato skin is prone to friction damage during mechanical harvesting. To reveal the friction damage mechanism of sweet potato skin, the impact friction process between a sweet potato and a rod was theoretically analyzed. The main factors affecting the impact friction force of the sweet potato skin include the sweet potato mass, drop height, distance from the center of the pendulum to the impact center of the sweet potato, maximum elastic displacement of the sweet potato, collision contact time, curvature radius of the sweet potato collision surface, material and roughness of the collision contact surface, etc. The mass, drop height, rod direction, rod state, and rod material of the sweet potato were used as the test factors, and the critical damage acceleration of the sweet potato skin was used as the test evaluation index. The results showed that the friction force caused by the collision between the sweet potato skin and rod increased with the increase in the sweet potato mass. The minimum friction is 3.5 N. The critical damage acceleration of the sweet potato skin decreased with the increase in the sweet potato mass, and the drop height had no significant effect on the critical damage acceleration of the sweet potato skin. Compared with the vertical placement, the critical damage acceleration of the sweet potato skin was smaller when the rod was placed horizontally, and the damage was more likely to occur. Under the same conditions, the critical damage acceleration of the sweet potato skin when the rod is rolling is greater than that when the rod is fixed. The critical damage acceleration of the impact friction between the sweet potato and 65Mn rod is the smallest, and the critical damage acceleration of the impact friction with the 65Mn–leather rod is the largest.