Influence of moisture content and loading orientation on some mechanical properties of Mucuna flagellipes nut
2012
Aviara, N.A., University of Maiduguri (Nigeria). Dept. of Agricultural and Environmental Resources Engineering | Onuh, O.A., University of Maiduguri (Nigeria). Dept. of Agricultural and Environmental Resources Engineering | Ehiabhi, S.E., University of Maiduguri (Nigeria). Dept. of Agricultural and Environmental Resources Engineering
The effects of moisture content and loading orientation on some strength properties of Mucuna flagellipes nut, namely bioyield, yield and rupture points; bioyield, compressive and rupture strengths; moduli of elasticity, resilience, toughness and stiffness, were determined at lateral and longitudinal axial loading using a Testometric Universal Testing Machine. In the moisture range of 3.38-10.7% (d.b.), bioyield, yield and rupture points of the nut decreased from 1,137 to 755 N, 1,157 to 790 N and 685 to 365 N, respectively, when loading was on the lateral axis, and increased from 1,090 to 1,888 N, 1,092 to 1,918 N and 420 to 1,215 N on longitudinal loading. Bioyield strength (1.83-1.41 N/square mm), compressive strength (1.85-1.44 N/square mm) and rupture strength (1.03-0.74 N/square mm) decreased with increasing moisture content under lateral loading, but increased from 4.05 to 8.17 N/square mm, from 4.15 to 8.45 N/square mm and from 2.6 to 6.3 N/square mm, respectively, as the moisture content increased in the above-mentioned range, under longitudinal loading. The elasticity, toughness and stiffness moduli of the nut decreased (23-16.6 N/square mm, 0.615-0.525 J and 272.8-250 N/mm, respectively) with increasing moisture content under lateral loading, and increased (34.5-66.56 N/square mm, 0.508-0.69 J and 246-369 N/mm, respectively) with moisture content on longitudinal loading. On the above loading orientations, modulus of resilience increased from 0.166 to 0.355 J, and from 0.255 to 0.576 J, respectively, with moisture content. The properties were higher on the longitudinal than lateral axial loading. Second order polynomial equations relating these properties to moisture content were established.
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