Effects of blades types on shear force and energy requirement of paddy stem

This study was aimed to determine of the shearing force and shearing energy of paddy stem as a function of blade type, blade-edge angle and cutting speed. The Karacadag white paddy variety was used as plant materials. Shearing properties were measured by a universal testing machine. Depend on measured shear force and cross-section area of paddy stem, energy values were calculated by measuring the surface area under the cutting force-deformation curve for each test separately. The tests were conducted at five blade angles, five loading speed with various three different type blades. The tests results showed that the shearing force, shearing strength, shearing energy, specific shearing energy and extension at maximum load were affected significant (p<0.01) by blade type, cutting angle and cutting speed. While the lowest values were determined at serrated 2 blade types, followed by the serrated 1 and flat-edge blade. The paddy stalk shearing force and energy values has increased with decrease in the blade edge angle from 90° to 50°. The highest force and energy values were measured at 90° cutting edge of blade as 25.47 N and 5.8 N cm. The effect of loading speed on the cutting forces, cutting strength, cutting energy and specific cutting energy were found significant (p<0.01). The shearing and energy has slightly decreased with an increase of blade cutting speed. While the highest values were found at 2 m s-1 loading speeds, the lowest values were found at 6 mm s-1 cutting speed.