选煤弧形筛的动力学及疲劳分析

发布时间：2018-05-15 05:15

本文选题：选煤弧形筛 + 筛板弧形座　；参考：《太原理工大学》2015年硕士论文

【摘要】：选煤弧形筛在工作中长期承受着交变激振力和物料的冲击、摩擦作用，其结构或部件容易产生疲劳破坏，致使工作效率下降和企业经济效益减少。为避免疲劳破坏带来的严重损伤，需要在设计阶段就对其结构或重要部件进行疲劳寿命分析。由于采用虚拟样机技术进行疲劳寿命分析相比于传统的物理样机试验法，具有节约人力资源、减少成本和缩短研发周期等优点，其越来越多被应用于研究与产品设计开发中。本文的研究对象是VSB302060型选煤弧形筛，通过有限元法所得应力结果与多体系统动力学仿真技术获取的载荷时间历程，分析其重要部件——筛板弧形座的疲劳寿命情况。首先，在了解VSB302060型选煤弧形筛的结构和工作原理的基础上，建立筛板弧形座的有限元模型，通过施加边界条件和载荷后，进行静强度计算，结果表明该部件的强度满足要求，同时获取疲劳分析所需的应力结果。然后，以多参考点最小二乘复频域法作为识别方法，运用LMS Test.lab对筛板弧形座进行模态分析，得到有利于振动的振型和固有频率，振动电机选用该频率对筛板弧形座进行激振，使其产生谐振，易于清理堵住筛缝的物料颗粒；基于拉格朗日法建立选煤弧形筛的力学模型和运动学微分方程，计算得到筛板弧形座和筛箱的位移幅值，并通过ADAMS中创建的多刚体系统模型仿真分析得到筛板弧形座和筛箱的振动位移曲线，，与理论分析结果相比较，验证了模型的准确性，同时其结果也表明筛板弧形座的振动位移远大于筛箱，有利于避免筛缝堵塞和减少筛箱疲劳破坏；在多刚体系统模型的基础上，将筛板弧形座柔化处理后替换掉原来的刚性体，从而建立起选煤弧形筛的刚柔系统模型，以此进行动力学仿真分析后输出筛板弧形座疲劳分析谐振下的载荷时间历程。最后，使用ANSYS14.5nCode DesignLife将筛板弧形座的静力学分析应力结果和载荷时间历程匹配形成以时间为变量的应力张量，结合材料的S-N曲线，应用Miner线性疲劳累积损伤法则，分析计算得到疲劳寿命比较小的危险位置，其循环次数为1.963109次，满足筛分机械的使用寿命要求。本文将有限元法和多体动力学仿真应用于选煤弧形筛的疲劳分析中，找出了重要部件筛板弧形座的薄弱地方，并得到了其疲劳寿命，可作为结构改进和使用维护的依据。该疲劳分析方法融合了强度分析、运动分析和疲劳分析，具有较好的可靠性和应用性，也体现出使用虚拟样机技术进行疲劳寿命分析的优越性。
[Abstract]:For a long time in the work of coal preparation arc screen is subjected to the impact of alternating excitation force and material friction. Its structure or components are easily damaged by fatigue which results in the decline of working efficiency and the reduction of economic benefits of enterprises. In order to avoid the serious damage caused by fatigue failure, the fatigue life of the structure or important components should be analyzed in the design stage. Compared with the traditional physical prototype test method, virtual prototyping technology has the advantages of saving human resources, reducing cost and shortening research and development cycle, so it is more and more used in research and product design and development. The research object of this paper is the VSB302060 type coal preparation arc screen. The fatigue life of the sieve plate arc seat is analyzed through the stress results obtained by the finite element method and the load time history obtained by the multi-body system dynamics simulation technology. First of all, on the basis of understanding the structure and working principle of VSB302060 type coal preparation arc screen, the finite element model of sieve plate arc seat is established. The static strength is calculated by applying boundary conditions and loads. The results show that the strength of the component meets the requirements. At the same time, the stress results of fatigue analysis are obtained. Then, the multi-reference point least square complex frequency domain method is used as the identification method, and the modal analysis of the sieve plate arc seat is carried out by using LMS Test.lab, and the vibration mode and natural frequency are obtained. The vibration motor chooses this frequency to excite the sieve plate arc seat. Based on Lagrangian method, the mechanical model and kinematics differential equation of coal preparation arc screen are established, and the displacement amplitude of sieve plate arc seat and screen box is calculated. The vibration displacement curves of sieve plate arc seat and screen box are obtained by simulation analysis of multi-rigid body system model created in ADAMS, and compared with theoretical analysis results, the accuracy of the model is verified. The results also show that the vibration displacement of the sieve plate arc seat is much larger than that of the screen box, which is beneficial to avoiding the clogging of the screen seam and reducing the fatigue damage of the screen box. On the basis of the multi-rigid body system model, the original rigid body is replaced by the flexible treatment of the sieve plate arc seat. Thus, the rigid flexible system model of coal preparation arc screen is established, and the load time history under resonance analysis is analyzed after dynamic simulation and output sieve plate arc seat fatigue analysis. Finally, ANSYS14.5nCode DesignLife is used to match the static stress analysis results of the sieve plate arc seat with the loading time history to form a time-dependent stress Zhang Liang. Combined with the S-N curve of the material, the Miner linear fatigue cumulative damage rule is applied. The dangerous position with relatively small fatigue life is obtained by analysis and calculation, and the number of cycles is 1.963109, which meets the service life requirement of screening machinery. In this paper, the finite element method and multi-body dynamics simulation are applied to the fatigue analysis of coal preparation arc screen. The weakness of the arc seat of sieve plate is found, and its fatigue life is obtained, which can be used as the basis for structural improvement and maintenance. The fatigue analysis method combines strength analysis, motion analysis and fatigue analysis. It has good reliability and application, and shows the advantage of using virtual prototyping technology to analyze fatigue life.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD452

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