Tensile Properties of Maize Stalk Rind

Experiments were carried out to measure the tensile properties of maize stalk rind. Two varieties of maize stalk (SD 12 and SD 9) and two moisture contents (fresh and air-dried) were tested. From each maize stalk sample, nine specimens (test coupons) of stalk rind were prepared to represent nine internodes from the bottom to the top of the maize stalk. The rind specimens were subjected to uniaxial tensile loading at a slow rate of 3 mm/min. From the recorded load-elongation curves, tensile stresses, modulus of elasticity, and tensile energy were determined. It was found that maize stalk rind exhibited elastic-plastic behavior, i.e., stress initially increased with strain in a linear fashion, and then nonlinearly until rupture. The measured ultimate tensile stress ranged from 178.15 to 80.53 MPa (average 122.26 MPa), elastic modulus from 35.01 to 11.38 GPa (average 19.32 GPa), and tensile energy from 0.004 to 0.099 J (average 0.032 J). Tensile strength, elastic modulus, and tensile energy decreased from the bottom to the top of stalk. There was a significant difference in tensile strength, modulus of elasticity, and tensile energy among two varieties and two moisture contents