Riswanti Sigalingging

Deformation Curve Characteristics of Rapeseeds and Sunflower Seeds Under Compression Loading

Abstract The deformation curve characteristics of rapeseeds and sunflower seeds compressed using the equipment ZDM 50-2313/56/18 and varying vessel diameters (40, 60, 80, and 100 mm) were investigated. Maximum compressive force of 100 kN was applied on bulk oilseeds of rape and sunflower of measured height 20-80 mm and deformed at a speed of 60 mm∙min-1. The compression test using the vessel diameters of 40 and 60 mm showed a serration effect while the vessel diameters of 80 and 100 mm indicated an increasing function effect on the force-deformation characteristic curves. Clearly, the increasing function effect described the region with oil flow and that of serration effect described the region without any oil flow. However, it was observed that the serration effect could be due to the higher compressive stress inside the smaller vessel diameters (40 and 60 mm) compared to those with bigger vessel diameters (80 and 100 mm). Parameters such as deformation, deformation energy, and energy density were determined from the force-deformation curves dependency showing both increasing function and serration effect. The findings of the study provide useful information for the determination of specific compressive force and energy requirements for extracting maximum oil from oilseed crops such as rape and sunflower.

Tangent Curve Function Description of Mechanical Behaviour of Bulk Oilseeds: A Review

Abstract The application of tangent curve mathematical model for description of mechanical behaviour of selected bulk oilseeds, namely jatropha, sunflower, rape, garden pea, and common bean in linear compression was reviewed. Based on the review analysis, the tangent curve function has been developed using MathCAD 14 software which employs the Levenberg-Marquardt algorithm for data fitting optimal for tangent curve approximation. Linear compression parameters including force (N), deformation (mm), energy (J), and/or volume energy (J-m-3) can equally be determined by the tangent model. Additionally, the theoretical dependency between force and deformation characteristic curves can be defined by the force coefficient of mechanical behaviour (N) and deformation coefficient of mechanical behaviour (mm-1) of the tangent model. In conclusion, the review results, however, shows that the tangent curve mathematical model which is dependent on experimental boundary conditions is potentialy useful for theoretical description of mechanical properties and deformation characteristics of bulk oilseeds in axial compression.

Application of a tangent curve mathematical model for analysis of the mechanical behaviour of sunflower bulk seeds

Abstract This paper evaluate the use of a tangent curve mathematical model for representation of the mechanical behaviour of sunflower bulk seeds. Compression machine (Tempos Model 50, Czech Republic) and pressing vessel diameter 60 mm were used for the loading experiment. Varying forces between 50 and 130 kN and speeds ranging from 10, 50, and 100 mm min-1 were applied respectively on the bulk seeds with moisture content 12.37±0.38% w.b. The relationship between force and deformation curves of bulk seeds of pressing height 80 mm was described. The oil point strain was also determined from the different deformation values namely 30, 35, 40, and 45 mm at speed 10 mm min-1. Based on the results obtained, model coefficients were determined for fitting the experimental load and deformation curves. The validity of these coefficients were dependent on the bulk seeds of pressing height, vessel diameter, maximum force 110 kN, and speed 10 mm min-1, where optimal oil yield was observed. The oil point was detected at 45 mm deformation giving the strain value of 0.56 with the corresponding force 16.65±3.51 kN and energy 1.06±0.18 MJ m-3. At the force of 130 kN, a serration effect on the curves was indicated; hence, the compression process was ceased.

Oil point and mechanical behaviour of oil palm kernels in linear compression

Abstract The study described the oil point and mechanical properties of roasted and unroasted bulk oil palm kernels under compression loading. The literature information available is very limited. A universal compression testing machine and vessel diameter of 60 mm with a plunger were used by applying maximum force of 100 kN and speed ranging from 5 to 25 mm min−1. The initial pressing height of the bulk kernels was measured at 40 mm. The oil point was determined by a litmus test for each deformation level of 5, 10, 15, 20, and 25 mm at a minimum speed of 5 mmmin−1. The measured parameters were the deformation, deformation energy, oil yield, oil point strain and oil point pressure. Clearly, the roasted bulk kernels required less deformation energy compared to the unroasted kernels for recovering the kernel oil. However, both kernels were not permanently deformed. The average oil point strain was determined at 0.57. The study is an essential contribution to pursuing innovative methods for processing palm kernel oil in rural areas of developing countries.

Mathematical Description of Non-linear Mechanical Behaviour of Materials Under Compression Loading, Case Study: Spruce Bulk Wood Chips

This communication discusses the mathematical description of mechanical behaviour of bulk spruce wood chips under compression loading. The dependency between compressive force and deformation curve characteristic was fitted by reciprocal slope transformation (RST) and tangent curve (TC) methods. The mathematical model coefficients of both methods were respectively determined by the least squares method and Marquardt Levenberg approximation process, all applicable in MathCAD software. It is confirmed here that both methods can suitably be used for the illustration of deformation curve characteristic of bulk spruce wood chips.