Mathematical description of loading curves and deformation energy of bulk oil palm kernels
¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Mechanical Engineering, Kamycka 129, CZ16521 Prague, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Engineering, Department of Material Sciences and Manufacturing Technology, Kamycka 129, CZ16521 Prague, Czech Republic
The study aimed at describing the experimental and theoretical relationships between the force and deformation curves as well as the deformation energy of bulk oil palm kernels under compression loading. Vessel diameters of 60, 80 and 100 mm with initial pressing heights of the bulk kernels measured at 40, 60 and 80 mm were examined by applying a maximum compressive force of 200 kN and a speed of 5 mm min-1. For the theoretical description of the force and deformation curves, the tangent curve mathematical model was applied using the MathCAD 14 software where the force coefficient of mechanical behaviour, A (kN), the deformation coefficient of mechanical behaviour, B (mm-1) and the fitting curve function exponent, n (-) were determined respectively. The determined coefficients in addition to the maximum deformation values obtained from the compression test were used for the estimation of the theoretical or analytical deformation energy. The determined regression models expressing the deformation, numerical energy and theoretical energy as well as the tangent model coefficients A and B dependent on the vessel diameter and pressing height were statistically significant (P < 0.05) or (F-ratio > F-critical). Improving the mechanical pressing of oil extraction for both domestic and industrial applications still remain a concern of researchers and engineers.