【作者】 朴香兰；

【导师】 王国强；

【作者基本信息】 吉林大学 ， 机械设计及理论， 2010， 博士

【摘要】 论文结合实际工程项目,对长距离平面转弯带式输送机设计中的若干关键技术问题,包括输送机转弯段托辊组布置方法、动力学建模及仿真技术、多点驱动技术及转弯段物料和输送带相互作用的离散元分析等进行了研究,为长距离平面转弯带式输送机设计提供依据。论文建立了平面转弯带式输送机转弯段输送带力学模型,分析了平面转弯带式输送机转弯处力的平衡条件和外曲线应力限制条件,导出了平面转弯带式输送机转弯半径的计算公式。在此基础上,对给定转向半径的带式输送机,实现了转弯段托辊组结构参数的优化设计。对平面转弯带式输送机动态特性进行了研究,建立了输送带、驱动装置、拉紧装置等单元的力学和数学模型,提出建模所需考虑的等效转化问题以及输送机运行阻力计算方法,并给出定解所需的边界条件和初始条件。编制了平面转弯带式输送机的动力学分析仿真程序,该程序能够完成动态分析所必须的常规设计、转弯段托辊组参数的优化设计、转弯半径计算、横向稳定性分析、非稳定工况下的动态分析等,并实现分析结果的可视化。对多滚筒、多点驱动时功率配比方法进行了讨论,提出了有中间驱动时张力计算及中间驱动点位置和数量的确定方法,通过驱动电机功率测试试验,验证了带式输送机的功率分配和驱动单元配置的正确。基于离散元法对转弯段的物料运动和料流对输送带的作用力进行了初步研究,模拟了输送带单元上物料的动态特性和输送带各部位所受的力,为带式输送机设计提供必要的基础数据。论文的理论研究成果和工程实用软件已应用于长距离平面转弯带式输送机设计,提高了带式输送机的设计水平。更多还原

【Abstract】 In the modern industrial enterprise, the belt-conveyor is the necessary subassembly which can form the rhythmic flow process transport line in the production process. New directions of the belt-conveyor are long-distance, high-power, high speed and high performance, also the conditions it working always is strict, many problems occur. The problems include that:①The engineer can’t adopt conventional design method of rigid body dynamics for design of long-distance belt conveyor. Viscoelastic properties of the belt and the kinetic tension should be considered when start-up and brake.②The direction has to change because the limit of landform. Lap joint or other special equipment used to be adopted,but they have much localization. In the past, using overlapping process and special redirection equipment lead to complex conveyor system and increased equipment; the impact of material caused by transshipment induces the acceleration of belt wear, the breakdown of conveyor in sever case and the tear of belt.③The excited frequency of the rollers is liable to lead to belt resonance in high speed belt conveyor. When the resonance happens,the avulsion or off tracking of belt must occur. So the design for avoiding resonance of the systerm should be executed.④To lower belt tension of long-distance conveyor, the driving power usually was distributed. Then the configuration and the number of intermediate driving point and the reasonable power ratio should be pay much attention to. Therefore, this thesis researched these problems in depth and meticulously. Our study combined the cooperation project with enterprise“Design of single 9.6km long-distance belt conveyor with horizontal curve”. This paper also began preliminary discussions on the application of the discrete element theory on the horizontal curve. This paper is as the following:1. Existing theories and methods of horizontal curve have been researched and analysed in-depth. Based on the pertinent theory such as the design process of the belt, the configuration of the curve and the limit of curve radial, the paper deduced the formula of the curve radial of belt conveyor with horizontal natural curve roundly under the conditions such as the geometry of the curve, mechanics analysis of the curve, force equilibrium of the curve and the stress and strain. And the comparison and analysis was made between the several existing formulas and this paper. To be able to choose reasonable structural parameters of the turning section, based on the new formula of turning radius, the optimization methods was established. The objective function is to minimize the difference between the initial radial and the calculated value. The optimization program was developed based on Matlab software and optimized process was achieved. The election of parameters was fast and convenient.2. The paper discussed system modeling theory of belt conveyor with horizontal curve in two aspects: vertical vibration, longitudinal and transverse coupling vibration of the belt. For the vertical vibration, the author built the dynamic models of the belt elements, driving elements and take-up system respectively. The vogit model with creep characteristic is selected for belt elements. The driving equipments contain electromotor, hydrodynamic coupling, reducer, arrester, coupler, and so on. Its model was built by equivalent method. Take-up device includes two degrees of freedom rotation and motation. The dynamic equation of the straight line segment element, the curve segment element, driving device and take-up device was established by Lagrange equations. And the necessary boundary conditions and initial conditions for the definite solution were given. The resistance of the belt is the major factor influencing the dynamic characteristis of the system. It’s also the major operation in conventional design. Therefore, the author puts forward the method of calculation for conveyor running resistance. The dynamics model of belt conveyor system with horizontal curve by synthesizing the models of the units.For the horizontal and vertical coupling two-dimensional vibration, the author meshed the elements using beam elements. And then, the element stiffness matrix, element mass matrix, element damping matrix and force vector matrix were established, the element stiffness matrix, element mass matrix, element damping matrix and force vector matrix in the overall coordinate system were established by transformation matrix. Finally, the horizontal and vertical two-dimensional mathematical model of the belt conveyor with horizontal curve was established. The mathematical model is the basis of computer simulation.3. According to the model, the solution of the dynamic model was discussed and a belt conveyor dynamic simulation program which integrates the conventional design and dynamic analysis was developed using MatLab. The program can complete a conventional design, curvature radius calculation of the curve section, optimizing design of curve section, stability design, dynamic analysis of starting phase and so on. We can obtain kinetic parameters at different time and different units through dynamic analysis and visualize the kinetic parameters. The speed curve, acceleration curve, displacement curve and start-tension curve of the head unit, tail unit and tension roller of the starting phase were obtained from simulating the system. Moreover, there were similar results compared with foreign literatures. The simulation results of the systemⅡwere satisfactory. The dynamics simulation programs can well satisfy the requirements for dynamic analysis of the design of long-distance, large-scale belt conveyor.4. The method for confirming the power ratio of the belt conveyor with multi-pulleys and multi-driving points and the various factors that affect the power ratio were studied. Further more, the belt tension of conveyor with midway driving units and the position and quantity of midway driving point are discussed. The correctness of the power allocation algorithm of high-power belt conveyor are confirmed by the power testing on the systemⅡ. We can calculate starting maximum power, starting overload coefficient, power ratio and power unbalance of motor on no-load starting and full load starting and mean power, average power utilization and power ratio of motor on no-load operation and full load operation based on the results of power testing. It is proved that the selected driving motor is reasonable.5. Through the discrete element theory, the exploratory research has been carried on to material movement on curve section and the mechanism of material flow effecting on the boundary. Using 3D modeling software CATIA, the geometry model of the conveyor belt is built, it has been put into commercial software EDEM subsequently, and the discrete element models of belt conveyor with horizontal curves and the material it transported is set up. The relationship between force and displacement is built by non-linear Hertz Mindlin contact model. In the EDEM platform, the simulation of massive particles is use of combination of four basic ball units. It well simulated the macroscopic law of material flow. The average pressure and maximum pressures suffered by conveyor belt under the conditions of various parameters were simulated, and also a good method for predicting the pressure suffered by curve section is provided.更多还原