Moisture content on the mechanical behavior of crambe grains

ABSTRACT: This study aimed to verify the influence of moisture content on the values of maximum compressive strength, proportional deformity modulus, elastic coefficients d, e, and f beyond the tangent values, and maximum grain drying of crambe (Crambe abyssinica Hochst) under compression in natural resting position. Crambe grains with moisture contents ranging from 0.1547 to 0.0482 decimal db were dried at 40°C and uniaxially compressed between two parallel plates in the natural rest position. The gravimetric method was used to monitor reduction in moisture content during drying (weight loss). It was concluded that the compression force required to deform the crambe grains decreases as the moisture content increases. The proportional deformity modulus increases as the deformation decreases, yielding values between (0.09-0.27)×102MPa. Sigmoidal model described by Taylor series adequately represents the compression resistance of crambe grains in the natural rest position with moisture content lower than 0.0813db.

摘要：本研究旨在验证含水率对自然静置受压状态下亚麻荠（Crambe abyssinica Hochst）籽粒的最大抗压强度、比例变形模量、切线值以外的弹性系数d、e、f以及籽粒干燥特性的影响。试验将干基含水率（以小数计）范围为0.1547~0.0482的亚麻荠籽粒置于40℃环境中干燥，并以自然静置状态在两块平行平板间进行单轴压缩试验，采用重量法监测干燥过程中的含水率变化（即质量损失情况）。研究结果表明：使亚麻荠籽粒产生变形所需的压缩力随含水率升高而降低；比例变形模量随变形量减小而增大，取值区间为(0.09~0.27)×10²MPa。采用泰勒级数（Taylor series）表述的西格莫伊德模型（Sigmoidal model），可较好地拟合干基含水率低于0.0813的自然静置受压亚麻荠籽粒的抗压性能。