To improve the application of discrete element models(DEM)to the design of agricultural crushers,in this study a new highly accurate model is elaborated.The model takes into account the fiber structure,porous nature o...To improve the application of discrete element models(DEM)to the design of agricultural crushers,in this study a new highly accurate model is elaborated.The model takes into account the fiber structure,porous nature of the material and the leaf sheath coating structure.Dedicated experimental tests are conducted to determine the required“intrinsic”and basic contact parameters of the considered banana straw materials.A large number of bonding parameters are examined in relation to the particle aggregation model in order to characterize different actual banana straws.Using the particle surface energy contact model,the viscosity characteristics of the crushed material are determined together with the related stacking angle(considered as the main response factor).Through single factor experiment analysis,it is found that when the surface energy is 0.9 J·m-2,the relative error between simulations and physical experiments is 5.288%.展开更多
为提高离散元法对指导香蕉秸秆粉碎还田装备设计与优化的准确性与可靠性,本文利用Hertz-Mindlin with bonding接触模型建立香蕉秸秆离散元粘结模型并进行参数标定。运用高速摄影技术开展碰撞恢复试验、静摩擦及滚动摩擦台架试验,确定了...为提高离散元法对指导香蕉秸秆粉碎还田装备设计与优化的准确性与可靠性,本文利用Hertz-Mindlin with bonding接触模型建立香蕉秸秆离散元粘结模型并进行参数标定。运用高速摄影技术开展碰撞恢复试验、静摩擦及滚动摩擦台架试验,确定了香蕉秸秆碰撞恢复系数、静摩擦因数和滚动摩擦因数等基本离散元模型接触参数。开展香蕉秸秆物理与仿真剪切试验,获得破坏香蕉秸秆外皮的力学特征曲线,确定物理最大剪切力为122.41 N;通过中心组合设计(Central composite design, CCD)响应面法确定香蕉秸秆粘结模型的法向接触刚度、切向接触刚度、临界法向应力与临界切向应力的最佳参数组合为5.89×10^(7)N/m、2.49×10^(6)N/m、1.39×10^(5)Pa、1.34×10^(5)Pa。以参数标定结果进行仿真验证,结果表明,仿真剪切力结果与物理剪切力相对误差仅为2.34%,验证了该粘结参数标定方法的可行性,可为香蕉秸秆粉碎还田机设计与研究提供理论参考。展开更多
基金Youth Fund of National Natural Science Foundation of China,61801175,JJ,https://www.nsfc.gov.cn/.
文摘To improve the application of discrete element models(DEM)to the design of agricultural crushers,in this study a new highly accurate model is elaborated.The model takes into account the fiber structure,porous nature of the material and the leaf sheath coating structure.Dedicated experimental tests are conducted to determine the required“intrinsic”and basic contact parameters of the considered banana straw materials.A large number of bonding parameters are examined in relation to the particle aggregation model in order to characterize different actual banana straws.Using the particle surface energy contact model,the viscosity characteristics of the crushed material are determined together with the related stacking angle(considered as the main response factor).Through single factor experiment analysis,it is found that when the surface energy is 0.9 J·m-2,the relative error between simulations and physical experiments is 5.288%.