Effects of moisture content, internode region, and oblique angle on the mechanical properties of sainfoin stem

Authors: MUSTAFA GÖKALP BOYDAŞ, MUSTAFA ÇOMAKLI, BAHADIR SAYINCI, MAZHAR KARA

Abstract: The effects of moisture content, internode region, and oblique angle on several mechanical properties of sainfoin stem were determined. The selected mechanical properties used were the shearing stress, specific shearing energy, bending stress, and modulus of elasticity when bending. The experiments were carried out with wet basis (WB) moisture contents of 71.76%, 45.57%, and 25.57%, at the third and second internode regions from the bottom up to the top, and 2 oblique angles (0° and 28°). The research results showed that the shearing stress of sainfoin stem increased as the moisture content increased, but decreased towards the upper internode of the stem. With the same moisture content, the shearing stress values obtained at an oblique angle of 28° were lower than those at an oblique angle of 0°. The maximum shearing stress and specific shearing energy were 5.76 MPa and 16.65 mJ mm^-2 with a WB moisture content of 71.76% and an oblique angle of 0° at the first internode, respectively. The bending stress increased with decreasing moisture content. The maximum bending stress was 36.45 MPa for the lower region with a WB moisture content of 25.57% and the modulus of elasticity when bending decreased with an increase in the moisture content, and it was towards the upper region. The average modulus of elasticity values varied between 1.60 and 0.64 GPa.

Keywords: Sainfoin, shearing stress, specific shearing energy, bending stress, modulus of elasticity

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