As forage chopper operates, there is a combined bending and torsional stresses acting on the driving shaft of the cutting and paddling mechanisms. Therefore, the objectives of this work were to determine the shear forces, reactions and bending moments on the driving shaft of a multi- crop paddle-thrown forage chopper. The diameter of the shaft was designed using the mathematical equations as given by Khurmi and Gupta and selected from the preferred and the not preferred diameters as prescribed by the American Society of Mechanical Engineering, New York, NY, USA. The shear forces and bending moment diagrams were drawn using Microsoft simple shapes diagram. The materials used were from mild steel. A factor of safety of 1.5 was used. More so, the shaft was carrying cutters and paddles to chop and paddle out forages from a forage chopper. The result of the design gave a shaft in series of diameters 35, 75 and 35mm respectively. The shear forces are S.FA = 26.63N, S.FC = -4.57N, S.FD = -25.74N, and S.FB = -25.74N at points A, C, D, and B respectively when the shaft is carrying the cutting and the paddling mechanisms with bending moments of MA = 0, MC = 4.26Nm, MD = 25.74× 0.13 = 3.34Nm, MB = 0. Where; MA, MC, MD and MB are bending moments at points A, C, D and B respectively. In addition, the shear forces and bending moment when the shaft is under its self-load are RA = 170N, RB= 170 and BMA = BMB = 0, BMX = 29.32Nm, at point A, B and X respectively. The shaft was able to withstand the strength and rigidity required for the cutting of forages and paddling of such out of the machine’s drum
Keywords: Bending Moments, Driving Shaft, Forage chopper, Shear Forces
