Simulation Research on Cotton Stalk Cutting and Crushing Based on ANSYS/LS-DYNA and Field Experiments

Abstract

In order to solve the problem of high straw content in recovered residual film and the low rate of qualified straw crushing in combination with a front-mounted cotton-straw-crushing device, the cutting and crushing mechanisms of cotton stalks were studied based on ANSYS/LS-DYNA. The height h and dip angle α of the fixed blade were determined to be 30 mm and 75° through a finite element analysis. On the basis of the device design, explicit dynamic models of the cutting and crushing of a single cotton stalk were established based on ANSYS/LS-DYNA. The results of the dynamic analysis revealed the cutting mechanism of the cotton stalk, and the influences of the cutting edge angle γ and front baffle height h1 on cotton stalk cutting were studied by using single-factor simulation tests. An edge angle of γ = 45° and a height of h1 = 265 mm were determined. Meanwhile, the mechanism of cotton straw crushing was revealed, and the motion states of the straw were studied at different times. The results of the simulation experiments on the influence of the cutter shaft’s rotational speed showed that with an increase in the cutter shaft’s speed, the rate of qualified crushing and the removal rate were both increased. At the design speed of n = 1800 RPM, the rate of qualified crushing was 84.6%, and the removal rate was 95.1%. Then, field experiments were carried out. The test results were as follows: the stubble height was 8.0 cm, the rate of qualified straw crushing was 91.8%, the clearance rate of film-surface impurities was 92.3%, and the film content was 3.6%, which met the working quality requirements (not less than 85%) of NYT 500-2015: “Operating quality for straw-smashing machines”.