基于粮堆有效摩擦系数分布规律的平底筒仓储料静态压力场计算方法

为准确描述筒仓储料内部任意一点的压力,同时考虑到筒仓中储料与仓壁以及储料与储料之间不一定处于临界滑动状态,其接触面上实际摩擦应力与法向压力之比≤最大静摩擦系数,定义了"有效摩擦系数",即2个物体接触面上的实际摩擦应力与法向压力之比,并对粮堆有效摩擦系数分布的进行有限元数值模拟,提出筒仓仓壁和粮堆内部有效摩擦系数分布规律的数学表达式;基于粮堆有效摩擦系数分布规律,采用储料纵向剖分和微元体静力平衡分析的方法,提出筒仓储料静态压力场计算方法;将本研究结果与数值模拟和Janssen公式计算结果进行对比分析。结果表明:1)本研究计算方法能够计算得到储料内部任意一点的竖向压力和水平压力以及筒仓侧压力,同时能够得到同一水平面上竖向压力分布的非均匀性;2)采用本研究计算方法计算得到的粮堆内部不同深度处的压力与数值模拟结果相比较,两者存在一定差异;3)采用本研究计算方法计算得到的筒仓侧压力与数值模拟和Janssen公式计算结果相比较,三者相差不大。研究可为粮食行业内涉及储料散体压力场的诸多问题提供理论支持。

Calculation method for static pressure field of bulk material in silo based on distribution law of effective friction coefficient in grain pile

The aim of this study is to accurately describe the pressure at any point inside the bulk material in silo.By considering that the interface between bulk material in silo and silo wall and the interface between bulk materials are all not necessary in the critical state of relative sliding and thus the ratio of the actual friction force to the normal force on the contact interface is less than or equal to the maximum static friction coefficient,"effective coefficient of friction",which represents the ratio of actual frictional stress and normal stress on the contact surface of two objects,is defined.Firstly a finite element numerical simulation for the distribution of the effective coefficient of friction in grain pile is carried out,and the mathematical expression for the distribution law of effective friction coefficient on silo wall and effective friction coefficient in interior of grain pile are presented;Then based on the distribution law of effective friction coefficient of grain pile and the bulk material in the silo is divided and static equilibrium analysis of grain pile infinitesimal is used,the calculation method of static pressure field of bulk material in silo is presented;The calculated results of this study are compared and analyzed with the numerical simulation values and Janssen formula.The results show that:1) The vertical and horizontal pressures at any point in the bulk material and the lateral pressures of the silo can be calculated,and the non-uniformity of the vertical pressure distribution on horizontal plane of grain pile can be obtained by the method of this study;2) Compared with the numerical simulation results,the pressures at different depths in interior of grain pile calculated by the method of this study are different;3) Compared with the results of numerical simulation and Janssen formula,the lateral pressure of silo calculated by the method of this study has little difference.