某漏斗车卸货时间与端侧墙侧压力的离散元分析

Discrete Element Analysis of Discharging Time and Lateral Pressure of a Hopper Car

针对某矿石漏斗车内部矿石的散体特性,采用离散单元方法构造矿石颗粒,对矿石车卸货过程进行模拟,并与现场试验进行对比.分析摩擦系数对卸货时间、侧压力分布的影响,讨论非直壁端侧墙的侧压力分布情况并与标准对比.结果表明:当摩擦系数从0.364增大到0.839,卸货耗时增加约30%,随着摩擦系数的增加,卸货耗时变长;摩擦系数在0.577~0.7范围内,卸货耗时与试验数据相吻合;当摩擦系数从0.466增大到0.7,侧压力值减少13%.同时讨论了非直壁端侧墙侧压力的分布情况,分析表明:侧压力大小与装载高度之间呈非线性分布,与标准中三角形分布规律存在差异,端侧墙的最大侧压力出现在■处,约为TB/AAR标准最大侧压力值的1.2倍,端侧墙的墙趾处有压力松弛,与试验结果一致.

The ore particles are constructed by discrete element method according to the granular characteristics of the ore particles.The whole unloading process is simulated by the ore hopper car model and compared with the test.The effect of the different friction coefficients on the discharging time and the lateral pressure is analyzed,and the lateral pressure distribution of non-straight walls is discussed and compared with the standard.The results show that when the friction coefficient is increased by 1.3 times from 0.364 to 0.839,the discharging time is increased by about 30%.As the friction coefficients increase,the discharging time of the ore hopper car takes longer.When the friction coefficient is 0.577-0.7,the discharging time is consistent with the test data.When the friction coefficient is increases by 0.5 times from 0.466 to 0.7,the pressure value is decreased by 13%.At the same time,the lateral pressure between the ore particles and non-straight walls is analyzed.Through the analysis,it is found that the lateral pressure distribution with height are nonlinear,which is different with the standard.The maximum lateral pressure of the walls is appeard at 2/3 H,which is about 1.2 times of the standard value.There is stress relaxation at the toe of the walls,which is closer to reality.Through the research,analysis and experiment comparison,the application of the discrete element method can provide an auxiliary support for the design of the hopper car.