CALIBRATION OF SOIL DISCRETE ELEMENT CONTACT PARAMETER IN RHIZOME MEDICINAL MATERIALS PLANTING AREA IN HILLY REGION
In view of the lack of accurate and reliable discrete element simulation parameters for the study of soil-machine interaction mechanism and machine design in the planting area of rhizome medicinal materials in hilly region. The angle of repose tests of soils were conducted to calibrate contact parameters between soil particles and sliding tests of soils were conducted to calibrate contact parameters between soil and machinery.The multi-variate regression models of the angle of repose and sliding angle were established using the Box-Behnken optimization method. Taking the measured angle of repose and sliding angle of soils as optimization objectives, the optimal combination of contact parameters of soil particles. The optimal combination of contact parameters was used to conduct tests on the angle of repose and sliding angle of soils and the errors between simulation and physical tests are 3.94% and 3.66%, respectively. To further verify accuracy of the calibrated and optimized DEM parameters, field tests and simulation on rotary tillage and ridging work were carried out for comparison. The relative errors in the ridge height, top width of ridges, and bottom width of ditches in the simulation results and field test results are 4.45%, 6.96%, and 8.56% (all within acceptable ranges). The rotary tillage and ridging effects are consistent in simulation and field tests, confirming the accuracy and reliability of the calibration of soil parameters.
Abstract in Chinese