Abstract:When the interaction between agricultural machinery and soil is simulated, the accuracy of the chosen particle parameters will directly have an effect on the simulation results. A systematic method for calibrating the interaction parameters of sand particles was proposed based on the combination of experiment and simulation. By the repose angle test apparatus, the triaxial shearing test instrument and the particle image analysis system equipment, the repose angle of the sandy soil, the shear modulus, the particle size distributions and morphology were obtained, which provided reference for particles or factory modeling. The standard ball and non-standard ball were used to calibrate the coefficient of restitution, coefficient of static friction and coefficient of dynamic friction between particles. The effect of different qualities and different calibration methods (drawing plate method and funnel method) on the repose angle were studied. The effect of different qualities of the soil on repose angle was small, and it can be ignored. Meanwhile, there was no significant difference between the two calibration methods. When the standard ball was used for calibration, the repose angle obtained from the simulation was closest to that of the test (coefficient of restitution was 0.15. coefficient of static friction was 0.8, and coefficient of dynamic friction was 0.2). The repose angle of drawing plate method was 33.99°, and the relative error was 4.74%. The repose angle of the funnel method was 33.59°, and the relative error was 3.51%. When the non-standard ball was used for calibration, the repose angle of the drawing plate method was 32.06°, and the relative error was 1.20% (coefficient of restitution was 0.15, coefficient of static friction was 0.2, and coefficient of dynamic friction was 0.3.). It can be seen that the effect of particle appearance on the coefficient of static friction was relatively large. The result provides a new idea and method for the calibration of particle parameters.
