Authors

Abstract

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

摘要 针对丘陵山区根茎类中药材种植区土壤-机械互作机理研究以及机具设计缺乏准确可靠的离散元仿真参数的问题。采用土壤休止角试验校准土壤颗粒之间的接触参数，采用土壤滑动试验校准土壤与机械之间的接触参数。采用Box-Behnken优化方法建立了静止角和滑动角的多元回归模型，以实测的土壤堆积角、滑落角作为优化目标值，获得土壤颗粒间的最佳接触参数组合。以最优组合进行堆积角试验和滑落角试验，仿真试验和物理试验之间的误差分别为3.94%、3.66%。为进一步验证标定优化的离散元模型参数的准确性，采用旋耕起垄田间试验和仿真试验进行对比分析，获取垄高、垄顶宽、沟底宽仿真试验结果与田间试验结果的相对误差分别为4.45%、6.96%、8.56%，误差在可接受范围内。仿真试验和田间试验旋耕起垄效果基本一致，验证了土壤参数标定的准确可靠。