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 bladetype, blade-edge angle and cutting speed. The Karacadag white paddy variety was used as plant materials. Shearingproperties were measured by a universal testing machine. Depend on measured shear force and cross-section area ofpaddy stem, energy values were calculated by measuring the surface area under the cutting force-deformation curvefor each test separately. The tests were conducted at five blade angles, five loading speed with various three differenttype blades. The tests results showed that the shearing force, shearing strength, shearing energy, specific shearingenergy and extension at maximum load were affected significant (p<0.01) by blade type, cutting angle and cuttingspeed. While the lowest values were determined at serrated 2 blade types, followed by the serrated 1 and flat-edgeblade. 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. Theeffect of loading speed on the cutting forces, cutting strength, cutting energy and specific cutting energy were foundsignificant (p<0.01). The shearing and energy has slightly decreased with an increase of blade cutting speed. Whilethe highest values were found at 2 m s-1 loading speeds, the lowest values were found at 6 mm s-1 cutting speed.