Influence of moisture content and loading orientation on some mechanical properties of Mucuna flagellipes nut
N.A. Aviara, O.A. Onuh, S.E. Ehiabhihttps://doi.org/10.17221/12/2011-RAECitation:Aviara N.A., Onuh O.A., Ehiabhi S.E. (2012): Influence of moisture content and loading orientation on some mechanical properties of Mucuna flagellipes nut. Res. Agr. Eng., 58: 66-72.
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; and moduli of elasticity, resilience, toughness and stiffness were determined at lateral and longitudinal axial loading, using a Testometric Universal Testing Machine (UTM). 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/mm2), compressive strength (1.85–1.44 N/mm2) and rupture strength (1.03–0.74 N/mm2), decreased with increase in moisture content under lateral loading, but increased from 4.05 to 8.17 N/mm2, 4.15 to 8.45 N/mm2 and 2.6 to 6.3 N/mm2, respectively, as the moisture content increased in the above range, under longitudinal loading. The elasticity, toughness and stiffness moduli of the nut decreased (23–16.6 N/mm2, 0.615–0.525 J and 272.8–250 N/mm, respectively) with increase in moisture content under lateral loading, and increased (34.5–66.56 N/mm2, 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 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.Keywords:
bioyield; compressive tests; modulus of elasticity; rupture; strength properties; Nigeria