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Mechanised harvesting of sugarcane can significantly reduce harvesting costs and improve efficiency. However, there are currently issues with poor chopping performance and significant losses of sugarcane juice. This study aimed to investigate the chopping and damage mechanisms of sugarcane and improve the performance of the chopping system through kinematic and dynamic analysis and finite element simulation. Firstly, the factors affecting the chopping performance and causing sugarcane damage were studied by establishing the kinematics and dynamics models of the chopper. The types of sugarcane damage and sugarcane fragments were summarised. Then, a finite element model of the chopping system was built. An anisotropic and nonlinear material model for sugarcane was developed using Fortran. The transient process of chopping was analyzed by the explicit dynamic analysis method, and the chopping and damage mechanism of sugarcane was revealed. The results indicated that a smaller thickness and bevel angle of blade led to a shorter chopping time and a smoother chopping surface. The upper and lower blades of the chopper had unequal axial chopping depths, which was the primary cause of sugarcane damage. The rotational speed ratio of conveying roller to chopping roller and the blade thickness affected step degree of chopping surface. Finally, the chopping system was improved according to the theoretical and simulation analysis results. Experimental results showed that the damage rate decreased by 6.8%, 12.2%, and 12.6% respectively, and the loss rate decreased by 8.1%, 13.9%, and 21.8%, respectively, when the feed rate was 1, 2, and 3 kg s−1. The study results provide a reference for the design and optimization of sugarcane harvester's chopping system. • Kinematics and dynamics of sugarcane chopping process were analyzed. • The types of sugarcane damage and fragments were summarised. • Chopping and damage mechanism of sugarcane were analyzed by finite element method. • Proposed suggestions for improving the chopping system and verified by tests. [ABSTRACT FROM AUTHOR]

Sugarcane harvester extractors are used to separate impurities during mechanical harvesting and their performance directly determines the impurity content of sugarcane billets. In this study, computational fluid mechanics (CFD) was used to analyse the flow field near the impeller of original design of extractor. The SST k-ω model and realisable k-ε model were used to calculate the turbulence in 2D and 3D flow fields respectively. The simulation results of 2D models showed that sharply shape from the leading to trailing edges of the original blade design could cause more energy losses. An improved blade design with smoother leading edge and trailing edges had improved performance with a maximum lift coefficient increased by 28.7%. 3D simulation results showed that when the fan speed was 1050 rpm, 1350 rpm and 1650 rpm respectively, the total pressure efficiency of the improved extractor was 11.45%, 9.03% and 6.7% higher than the original extractor, respectively. Impurity content experiments showed that when the feed rate was 1 kg s−1, 2 kg s−1 and 3 kg s−1, compared with the original extractor, the impurity content of the improved extractor decreased by 0.46, 0.41 and 0.71 percentage points at most. The results showed that the impurity content and energy consumption of the improved extractor was less than that of the original design of extractor. • Study proposes improvement method of extractor blade using CFD. • Improvements suggested by CFD models verified by experiment. • Blade modified by simple changes improved aerodynamic performance of extractor. • Modified blade enhanced cleaning performance and energy utilisation. [ABSTRACT FROM AUTHOR]

The problem of sugarcane top anti-tangling in the silage industry is based on mechanical properties, but there have been no studies on variables and models that can be used to predict them. The aim of this study was to examine how the physical properties, microstructure, and chemical composition of sugarcane top stems, leaves, and veins impact their mechanical properties and evaluate their role in entanglement within the silage industry. This study was carried out by using Grey Relational Analysis (GRA) and Multiple Linear Regression (MLR) to analyze the relationship and the influence level between the influencing factors (number of segments, diameter (width), segment distance, density, water content, hemicellulose content, cellulose content, and lignin content) and the mechanical property (tensile strength) of sugarcane tops. The results showed that the determination coefficients of tensile strength on stems, leaves, and veins were 0.9498, 0.9503, and 0.9457 by regression fitting, respectively. The RPD of the prediction model was greater than 3 and the RSEP was all less than 5%, which indicated that the model had a high prediction accuracy. It showed that the influencing factors and the mathematical model can be used to build the mechanical model of sugarcane tops, which was the basis for obtaining the data needed to study the anti-tangling of mechanical equipment. • Anti-tangling problems in the sugarcane top silage industry were analyzed. • Sugarcane tops were studied in a multi-scale and multi-faceted manner. • The factors rank influence the tensile properties of sugarcane tops were obtained. • The determination coefficients were 0.9498, 0.9503, and 0.9457, respectively. • The RPD of the prediction model was greater than 3 and the RSEP was less than 5%. [ABSTRACT FROM AUTHOR]