Bending and Shearing Properties of Wheat Stem of Alvand Variety

Shearing stress of wheat stalk was measured for four moisture content levels (15, 25, 35 and 45%, w.b.), three cutting heights (100, 200 and 300 mm), two types of cutting knives, smooth and serrated edge and three blades oblique angle (0, 15 and 30 deg.). The results of data analysis showed that the shearing stress of wheat stems decreased as the moisture content decreased. The shearing force of stems, decreased as the cutting height of stalk increased, because of a reduction in stalk diameter. Shearing stress was lower by using smooth edge knife, because of less friction than serrated one. The blade oblique angle of 30 degree showed the least shearing stress. The average of shearing stress varied between 3.25 and 3.86 MPa. Bending stress and modulus of elasticity increased as the moisture content decreased and decreased as the cutting height of stem increased. The average of bending stress varied between 17.74-26.77 MPa and modulus of elasticity varied between 3.13-3.75 Gpa.