Simulation Research On Working Process Of Flexible Cutter Of A Sugarcane Leaf Cutting And Returning To Field Machine

This paper took the second generation of the sugarcane leaf cutting and returning to field machine as the research object. Based on the arbitrary Lagrangian-Eulerian(ALE) method, a fluid-structure interaction simulation of flexible cutter's working process of the sugarcane leaf cutting and returning to field machine was carried out, exploiting the finite element software LS-DYNA.The simulation research were mainly aimed at the self-excitation airflow field caused by different knife rollers rotation modes in working process, the process of cutting off sugarcane leaves and the impacts of flexible cutters on sugarcane ratoon during cutting off sugarcane leaves. At the same time, the related experiment verification was launched to inspect the simulation validity, which could provide reference for further optimization of knife rollers and diversion cover of the sugarcane leaf cutting and returning to field machine.The simulation and analysis of the self-excited wind field under different knife rollers operation modes and the wind speed experiment of the wind field were carried out. Through the comparison of the simulation results, two knife rollers operation modes that two knife rollers in clockwise rotation and clockwise rotation of the master knife roller while anticlockwise rotation of the slave knife roller were selected. Under the condition of two knife rollers in clockwise rotation, the movement of air flow was mainly concentrated in the motion plane of flexible cutter. The air flow caused by the two knife rollers were interacting near the ground between two knife rollers and an airflow convergence surface was generated in between these two knife rollers during the process of the airflow interaction, accompanied by the formation of vortices. The wind field variations were most regular and stable in regions near the ground between the two knife rollers, the left and right outlets of the diversion cover. The airflow in region near the ground between the two knife rollers and the left outlet of the diversion cover was upper-left, while the airflow in right outlet of diversion cover was moving to the upper right. Under the condition of clockwise rotation of the master knife roller and anticlockwise rotation of the slave knife roller, the air flow formed by the two knife rollers were interacting near the top of diversion cover between two knife rollers. The airflow was weakened by the impact of each other and it was downward after interaction. The intensity of airflow has been greatly reduced when reaching the ground, the wind speed near ground of which was smallest of all the knife rollers operation modes. The wind field variations were most regular and stable in the left and right outlets of the diversion cover. The airflow in the left outlet of the diversion cover was upper-left, while the airflow in right outlet of diversion cover was moving to the upper right. Moreover, a hot wire anemometer was applied to measure the wind velocity in regions near the ground between the two knife rollers, the left and right outlets of the diversion cover. Comparing the simulation data with the experimental data, although there was a big difference, the change trend of simulation and experimental data was similar, which could prove the simulation result was reasonable in certain extent.The simulation of the process of cutting off sugarcane leaves was carried out, and the high-speed camera was used to shoot the cutting process. From the comparison of simulation results of cutting off sugarcane leaves between two knife rollers in clockwise rotation and clockwise rotation of the master knife roller while anticlockwise rotation of the slave knife roller, it was obtained that the optimal operation mode was the clockwise rotation of the master knife roller while anticlockwise rotation of the slave knife roller. Under this operation mode, the cut-off sugarcane leaves were moving toward and discharging from the left and right outlets of the diversion cover. But it could also cause intertwist problems, when the discharge of sugarcane leaves was block and sugarcane leaves were brought into the diversion cover by the flexible cutter. What' more, the high-speed camera was used to implement the experiment of shooting the process of cutting off sugarcane leaves in different knife rollers operation modes. From the experiment results, it was observed that the movements of cut-off sugarcane leaves were similar with the simulation result, which could verify the validity of the simulation.The simulation research of the impacts of flexible cutters on sugarcane ratoon during cutting off sugarcane leaves was developed. The simulation results showed that the maximum stress of sugarcane skin and sugarcane core was 2.68 MPa and 0.57 MPa respectively, which was less than the compressive strength of the stubble of sugarcane stalk. Therefore, the flexible cutter would not cause damage to the sugarcane ratoon. Furthermore, the soil stress sensor was applied to collect the stress data of the flexible cutter hitting the ground. Meanwhile, the stress data of the corresponding position unit in the simulated soil model were extracted and compared with the experimental data, which could inspect the simulation validity.