Evaluation of Engineering Properties of Groundnut Plants and Pods for Efficient Pod Stripper Design

Abstract

Efficient mechanization of groundnut stripping necessitates a detailed understanding of the crop’s physical and mechanical properties to support the design and optimization of threshing and stripping equipment. This study evaluated the key engineering characteristics of groundnut plants and pods to aid in developing an efficient pod stripper. The number of pods per plant ranged from 18 to 40 (mean 28.91), with an average of 10.67 branches and 912.98 g plant weight with pods. The mean pod dimensions—length, width, thickness, and geometric mean diameter—were 33.04 mm, 12.39 mm, 11.01 mm, and 16.47 mm, respectively. Bulk and true densities were 279.84 kg/m³ and 574.60 kg/m³, corresponding to a porosity of 50.72%. At 20% moisture content, the sphericity, aspect ratio, surface area, and volume averaged 0.59, 2.70, 855.84 mm², and 755.86 mm³, respectively. Mechanical parameters included an angle of repose of 25.9°, terminal velocity of 9.08 m/s, and coefficients of static friction of 0.36, 0.44, and 0.39 on glass, steel, and plywood surfaces, respectively. Rupture forces were highest in the lateral direction (240.23 N), followed by longitudinal (64.36 N) and vertical (32.74 N) orientations. The findings indicate that pod geometry, density, and frictional behaviour critically influence the design of stripping and cleaning units, such as concave clearance, drum configuration, and blower velocity. Overall, the evaluated properties establish a reliable database for optimizing pod stripper design, enhancing operational efficiency, minimizing pod breakage, and promoting cost-effective, energy-efficient, and farmer-friendly mechanized solutions for sustainable groundnut production.