基于HSCM和LCM的分层砂土与触土部件互作参数标定与试验

Calibration and Experiment of Interaction Parameters between Layered Sandy Soil and Contact Components Based on HSCM and LCM

摘要:

为探究北方露地葡萄砂性土在纵深方向上的性质差异及其与开沟触土部件的互作机理，本文针对砂性土上、中、下3层土壤建立了离散元仿真模型，并选用滞后弹性模型（Hysteretic spring contact model, HSCM）和线性粘聚力模型（Liner cohesion model，LCM）作为接触模型。通过圆筒提升试验及图像处理技术测得各层土壤堆积角。利用小球滚动和碰撞反弹试验测定了滚动摩擦因数和恢复系数。以土壤颗粒间接触参数为试验因素，以堆积角为试验指标，进行三因素三水平试验，建立土壤堆积角回归预测模型，得到3层土壤滚动摩擦因数为0.07、0.17和0.21，恢复系数为0.47、0.52和0.62，粘聚能量密度为2694、4266、4432J/m3。通过对土壤屈服试验和斜面试验，测得各层土壤屈服强度和滑动摩擦角，并进行通用旋转中心组合模拟试验，确定各层土壤与触土部件静摩擦因数、滚动摩擦因数和恢复系数。在标定参数下，3层土壤堆积角仿真与物理试验误差分别为1.7%、2.6%、5.0%。为验证土壤与触土部件标定参数准确性，在开沟装置后方增设半边罩壳（一侧有罩壳一侧无罩壳），进行田间抛土试验。试验结果表明，有罩壳和无罩壳一侧土壤抛掷距离分别为101.4、235.3mm，与仿真值误差仅3.34%和8.73%，表明仿真模型准确可靠。研究结果可为后续土壤与触土部件互作分析提供理论基础。

Abstract:

To accurately represent the property differences in the vertical direction of sandy soil in northern open-field vineyards and address the lack of reliable discrete element simulation parameters in the study of interaction mechanisms with soil-touching components, simulation models for the upper, middle, and lower layers of sandy soil in open-field vineyards were established. The hysteretic spring contact model (HSCM) and linear cohesion model (LCM) were used as the contact models between soil particles. Firstly, the pile angle of each soil layer was obtained through cylindrical uplift tests combined with image processing technology. The rolling friction coefficients and restitution coefficients were measured by using rolling ball and collision rebound tests. With soil particle contact parameters as experimental factors and stacking angle as the indicator, a three-factor three-level experimental design was conducted to establish a regression prediction model for the soil stacking angle. The rolling friction coefficients for the three layers of soil were found to be 0.07, 0.17, and 0.21, respectively, with restitution coefficients of 0.47, 0.52, and 0.62, and cohesion energy densities of 2694J/m3, 4266J/m3, and 4432J/m3. Yield strengths of each soil layer were measured through soil yield tests. Secondly, the contact parameters between the soil and soil-touching components were calibrated. The sliding friction angles of each soil layer were determined through slope tests. With soil particle and soil-touching component contact parameters as experimental factors and sliding friction angle as the indicator, a general rotational center combination simulation test was conducted. Under the calibrated parameters, the errors between the simulated and actual stacking angles for the three soil layers were 1.7%, 2.6%, and 5.0%, respectively. To validate the accuracy of the calibrated parameters, field soil throwing tests were conducted, showing that the throwing distances for covered and uncovered sides of the soil were 101.4mm and 235.3mm, respectively, with errors of 3.34% and 8.73% compared with the simulation values. The relatively small errors indicated that the simulation model was accurate and reliable. The results can provide a theoretical basis for subsequent interaction analysis between soil and soil-touching components.