Tensile Strength and Shear Strength of Switchgrass Before and After Frost

Abstract

Knowledge of the physical properties of lignocellulosic biomass is important for the design and execution of field operations such as harvesting, baling, and size reduction. In this study, the tensile strength and the shear strength of Kanlow switchgrass before and after frost for internodes 2 and 3 were measured. The shear strength was measured using a double shear box, and the tensile strength was measured using a special test sample preparation that provided controlled failure of samples. The experiments were conducted for eleven sampling periods: before frost (sampling periods 1 to 4) and after frost (sampling periods 5 to 11). The moisture content before and after frost was significantly different (p < 0.0001). The reduction in moisture content after frost has potential benefits for various field operations such as windrowing without conditioning, baling without raking, easy handling due to safe storage moisture, and efficient preprocessing. The mean tensile strength before frost was significantly greater than that after frost (p < 0.0001). The mean shear strength for internodes 2 and 3 had the highest value for the first sampling period and the lowest value for the last sampling period. The mean tensile strength was approximately three times the mean shear strength.