基于DEM法的旋耕刀具耕作过程分析与研究

发布时间：2018-01-03 20:34

本文关键词：基于DEM法的旋耕刀具耕作过程分析与研究　出处：《河北科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：旋耕刀是旋耕机的主要工作部件,由于其工况下转速快、瞬时撞击力大、与土壤接触时接触机理复杂等原因,直接影响了旋耕机的旋耕效果、能量消耗、功率分配等重要问题,旋耕刀片长期与土壤接触,其结构强度也决定了旋耕机的寿命,因此研究旋耕刀片的动力学和静力学问题具有重要意义。本文以某型旋耕机的一组旋耕刀片为研究对象,根据离散元理论,首先建立了土壤的JKR模型,找到了土壤-耕刀的接触模型的必要参数,并建立了螺旋机的三维模型和找到旋耕机的相关参数。其次,探索不同粘结键能量土壤模型的耕作效果和耕刀的受力情况,确定适宜的粘结键能量模拟土壤,并改进耕刀形状,探究不同耕刀形状下的耕刀的受力状况。再次,针对耕刀在耕作过程中的运动情况复杂的问题,使用DEM与多体动力学软件耦合,对耕刀处在不同粘结键土壤情况下和不同形状的耕刀耕作情况进行了耦合仿真,得到了耕刀在相关工作条件下的角速度、角加速度、扭矩输出等动力学参数,通过对比分析耕刀运动状况,对耕刀改进提出合理建议。最后,利用原型耕刀在DEM仿真时刀具的受压力情况,将刀具的受力信息提取,导入到有限元软件行进耕刀的有限元仿真,得到了耕刀在工况下位移、应力、应变等主要信息,并根据位移、应力、应变等信息对耕刀的结构改进提出合理建议。文章以离散元理论中的JKR模型中颗粒具有粘结键能量适宜仿真土壤为理论基础,通过探究耕刀在不同粘结键能量的土壤耕作情况和不同形状耕刀的工作情况等问题,对耕刀耕作效果、耕刀受力、耕刀的动力学状况、耕刀的静力学状况等方面进行了深入的研究,利用研究结果提出了合理的改进建议。文章的研究成果不仅适用于旋耕刀具,更对工程土方机械、掘进机械、矿山机械等机械结构的优化改进具有指导性意义,具有广阔的应用前景。
[Abstract]:Rotary tillage knife is the main working part of rotary tiller. Because of its fast rotation speed, large instantaneous impact force and complicated contact mechanism with soil, it has a direct impact on rotary tillage effect and energy consumption of rotary tiller. Power distribution and other important problems, rotary tilling blade contact with the soil for a long time, its structural strength also determines the life of rotary tiller. Therefore, it is of great significance to study the dynamics and statics of rotary tiller blades. In this paper, a group of rotary tilling blades of a certain type of rotary tiller is taken as the research object. According to the discrete element theory, the JKR model of soil is first established. Found the necessary parameters of the soil-tillage knife contact model, and established the three-dimensional model of the screw machine and found the relevant parameters of the rotary tiller. Secondly. To explore different bond energy soil model tillage effect and force situation of tillage knife, determine the suitable bond energy to simulate the soil, and improve the shape of tillage knife. Thirdly, aiming at the complex movement of tiller in the process of tillage, we use DEM and multi-body dynamics software to couple. The coupling simulation of tillage tool in different bond soil and different shape tillage is carried out, and the dynamic parameters such as angular velocity, angular acceleration and torque output are obtained. By comparing and analyzing the movement of the tiller, the paper puts forward some reasonable suggestions for the improvement of the tiller. Finally, the force information of the tool is extracted by using the pressure of the tool when the prototype tiller is simulated by DEM. The finite element simulation of the tiller is introduced into the finite element software, and the main information of displacement, stress, strain and so on under the working condition are obtained, and according to the displacement and stress. Based on the JKR model of discrete element theory, the bond energy of particles is suitable to simulate the soil. Through probing into the tillage condition of different bond energy in soil and the working condition of different shape tillage knife, the effect of tillage knife, the force of tillage knife and the dynamic condition of tiller knife were studied. In this paper, the statics of the tiller is studied in depth, and the reasonable improvement suggestions are put forward by using the research results. The research results of this paper are not only suitable for rotary tillage tools, but also for engineering earthmoving machinery and tunneling machinery. The optimization and improvement of mining machinery and other mechanical structures is of guiding significance and has broad application prospects.
【学位授予单位】：河北科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S222.3

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