基于改进颗粒模型的筒仓卸粮宏细观力学响应模拟研究

Simulation of Macro&Micromechanical Response of Silo Unloading Based on Improved Particle Model

离散元模拟常作为研究筒仓卸粮的方法,但由于在模拟中所用颗粒模型多为单一ball单元模型,使得模拟卸粮的颗粒内摩擦远小于真实实验情况,从而导致模拟结果与实验结果误差较大。本研究在已有离散元程序基础上,添加了黏度系数较大的微型颗粒来模拟粉尘,建立了一种改进颗粒模型。基于合理的物理实验,从卸粮过程的宏细观力学响应角度深入探究了改进颗粒模型相对于传统ball单元模型的优势,结果表明,改进颗粒模型的仓壁侧压力曲线振荡幅度更大,与实验情况更吻合。改进颗粒模型的模拟数据曲线与物理实验数据曲线更接近,仓壁动态侧压力曲线标准差相比传统ball单元减小了77.3%。剪切力与位移曲线的标准差相比传统ball单元的标准差减小了12.5%,拟合效果更好。

Discrete element simulation is often used as a method to study silo unloading.As the particle model used in the simulation is mostly the single ball unit model,the internal friction of simulated particle is much smaller than it in the real test,resulting in a large error between simulation results and test results.To solve this problem,based on the existing discrete element program,this paper added micro particles with large viscosity coefficient to simulate dust,and established an improved particle model.Based on reasonable physical tests,this paper deeply explored the advantages of the improved particle model over the traditional ball element model from the perspective of the macro&micromechanical response in the unloading process.The results indicated that the wall pressure curve of the improved particle model was more consistent with the real situation,and the range of the maximum wall pressure was closer to the test results.The curve of the improved particle model was closer to that of the experiment,and the standard deviation of the wall pressure curve was 77.3%less than that of the traditional ball element model.Compared with the standard deviation of the traditional ball element,the standard deviation of the shear force-displacement curve was reduced by 12.5%.