Study on sugarcane chopping and damage mechanism during harvesting of sugarcane chopper harvester

Abstract

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.