Redesigning a Stalk Chopper Mechanism for Reducing Cutting Energy and Optimizing Its Bite Length

Considering the increasing population of the world and the lack of human food sources, it is very important to pay more attention to fodder plants that can indirectly supply human food. By using choppers, a large amount of fodder can be transported and prepared for anaerobic fermentation of fodder.  In this research, a control mechanism has been proposed to change the angle of the knives on the cutting drum with a tangent plane on the circumference of the drum in order to change the distance between the knives and the fixed knife and change the length of the pieces. The mechanism was analyzed in SAM software, and then the three-dimensional model of different blade angle states was designed and analyzed in CATIA V5 R21 software. According to the obtained data, although the Von Mises stresses occur at the minimum angle of 22 degrees and the maximum Von Mises stress occurs at an angle of 16.5 degrees, there is no significant difference in the amount of stresses. Therefore, this mechanism can be recommended for all the mentioned situations (angles). For 1600rpm rotational speed and 6083 N/m line force density the occurred Von Mises stress in 22 degree angle is lower than zero degree angle.