Abstract

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Yam is a tuber crop and its harvesting is a major challenge as a result of drudgery and high manpower requirement. Therefore, the objective of this study was to develop a tractor operated implement for the mechanization of yam harvesting. The most important component of a root and tuber harvester is the blade since it interacts directly with the soil as it cuts through the soil. During such operations, the blade is subjected to impact and high frictional forces that creates unbalanced forces which results in blade wear. In this research, different geometric model concepts of blades were modelled using CAD and McKyes three dimensional model was used to predict the draft force. Finite element method was implemented in ANSYS software and the trapezoidal-shape of blade was found to have a deformation of 0.0535 mm with a stress of 97.856 MPa. The finite element analysis results for the entire harvester assembly generally showed a maximum stress of 218 MPa which was less than the material stress of 250 MPa. This suggests that the entire harvester assembly was designed within the safe stress levels.The harvester was fabricated and tested under experimental field conditions.