颗粒滚动摩擦系数对颗粒堆内部受力的影响

为探究贮存过程中不同形状玉米颗粒与镀锌钢板间滚动摩擦系数对颗粒堆基底接触力分布的影响,采用离散元法数值模拟标定球形、锥形和矩形玉米颗粒间滚动摩擦系数。玉米颗粒形状越不规则,滚动摩擦系数越大,其中锥形玉米颗粒间滚动摩擦系数最大。以3种形状玉米颗粒与镀锌钢板间滚动摩擦系数为因素,以玉米颗粒与基底法向、切向接触力平均值为指标,作3因素5水平二次正交旋转组合模拟试验,运用Design-Expert8.0.6软件数据处理,基于结合响应曲面法分析试验结果。随玉米颗粒与镀锌钢板间滚动摩擦系数增加,玉米颗粒与基底间法向和切向接触力平均值均先增大后趋于稳定,且模拟试验得玉米颗粒与基底法向接触力分布规律与物理试验结果基本一致。研究结果可为粮仓设计及结构优化提供理论参考。

Effect of coefficient of rolling friction on internal force of particles pile

In order to explore the effect of coefficient of rolling friction between different shaped maize particles and zincified steel plate on the distribution of contact force on the basement under particles pile in the storage process,the coefficients of rolling friction of spherical,cone-shaped and rectangular maize particles were calibrated respectively by numerical simulation of discrete element method.The result showed the greater the degree of irregularity was,the bigger the intergranular coefficient of rolling friction was,the value of the intergranular coefficient of cone-shaped maize particles was the biggest.Regarding coefficient of rolling friction between three shaped maize particles and zincified steel plate as a factor,and regarding average values of normal and tangential contact forces between particles and basement as an indicator,the three-factor and five-level quadratic regression rotation design experiment was accomplished,and experimental data were processed by Design-Expert 8.0.6 software,the experimental results were analyzed by response surface methodology.The result showed that the average values of normal and tangential contact forces between particles and basement were increased initially and then stabilized,with the increase of coefficients of rolling friction between three shaped maize particles and zincified steel plate.Based on discrete element software,the maize particle accumulation experiment was carried out,it was concluded that the distribution law of the normal contact forces between maize particles and the basement was the same,and the results of accumulation experiment were basically consistent with physical experimental results.The study could provide theoretical references for design and structure optimization of the granary.