基于有限元的碟式分离机应力分析与结构优化

发布时间：2018-03-16 07:13

本文选题：碟式分离机　切入点：有限元分析　出处：《广东海洋大学》2013年硕士论文　论文类型：学位论文

【摘要】：随着全球能源与环保行业的迅猛发展以及国际形势日益复杂化，国防、冶金、食品、化工、核工以及药剂等行业高品位、高纯净的需求凸现和低碳经济全球化；分离机械工业越来越受到各国的重视，，对于碟式分离机来说，其生产数量与应用规模已经远超其他类型连续离心机总和，正常工作过程中，机器的结构安全性和加工稳定性显得尤为重要；针对当前碟式分离机转速不断提高、结构系统日益复杂化，采用经典弹性力学理论不能满足设计需要等问题；本文以LX-460型胶乳碟式分离机为研究对象，以提高结构安全性、降低应力水平为目标，结合有限元分析与理论计算，对其主要结构应力特性进行研究，提高分离效率与整机性能、降低劳动强度、增大生产能力。本文对碟式分离机结构进行研究的主要工作及所得研究结果如下：（1）转鼓结构应力特性研究研究转鼓工作转速空转状态与工作状态两种工况的结构应力特性，确定有限元分析约束条件，建立分析计算模型，比较转鼓两种工况下的应力分布规律；构造几何路径，研究转鼓螺纹牙、排料口等高应力区域的局部应力；改变工作转速，分析各工况结构应力与工作转速的变化规律；建立转鼓接触计算模型，进行有限元接触分析，研究接触分析过程中，不同刚度系数Knormal对接触模型计算速度与收敛曲线变化规律的影响，确定最优刚度。研究表明：结构整体应力水平分布不均，转鼓筒体沉渣区、转鼓侧壁、螺纹牙等位置局部应力水平很高，应采用结构优化等手段，考虑从降低结构应力集中、改善结构强度、结构轻量化等方面进行设计。（2）螺旋齿轮应力特性研究参数化构建螺旋齿轮实体模型，针对空间点接触类型的特殊性，建立啮合传动有限元计算模型，进行三维接触分析，比较不同齿对数啮合，接触应力变化情况；确定导热系数、对流换热系数、温度场约束条件，考虑螺旋齿轮啮合传动发热对胶合、齿面磨损、点蚀等失效形式的影响，将温度作为热载荷，进行热弹耦合分析，研究耦合场载荷分布规律。研究表明：不同齿对数接触，齿面接触应力分布规律基本相同，点接触条件下，耦合场应力水平较高，轮齿发热加剧了齿轮磨损速度，极大地影响了啮合效率，脉动循环交变应力引起齿轮、轴承的振动，导致转鼓不平衡，引起严重的后果。应优化结构参数，降低闭式齿轮箱发热及轮齿受载状态，提高传动效率。（3）评估有限元计算结果及强度校核采用无力矩、有力矩理论分析转鼓鼓壁以及边缘效应区的强度问题，理论分析螺旋齿轮的齿面接触疲劳强度、齿根弯曲疲劳强度，将理论计算结果与有限元分析结果进行对比，验证有限元建模分析计算方法的正确性，结合安定性原理及结构强度评定准则，进行强度评定，校核结构强度的安全性。研究表明：有限元法与现有理论方法得到的转鼓、螺旋齿轮应力分布规律基本接近，相对误差在20%以内，验证了有限元建模分析方法的正确性，通常情况下，理论方法进行应力计算与结构设计比较保守，通过结果比较，发现有限元法分析结构应力值比理论值稍大，这与现实相符，说明采用有限元法设计分离机结构更具先进性，有限元值进行强度校核，结构强度满足要求。（4）结构多目标驱动优化设计利用ANSYS Workbench环境中的多目标驱动优化技术（GDO），对碟式分离机转鼓锁环与螺旋齿轮进行多目标驱动优化设计分析，从安全性、经济性出发，结合优化目标函数敏感性分析与参数响应性分析，合理优化结构几何参数与性能参数，进行有限元分析与结构设计，比较优化前后结构目标函数的变化规律，确定最优结构参数。优化表明：优化后的结构应力分布相对比较均匀，应力集中减小，最大等效应力明显降低，材料消耗减少，结构综合性能得到一定的提高，对碟式分离机结构优化以及整机可靠性提高具有一定的价值。
[Abstract]:With the global energy and environmental protection industry, the rapid development and the international situation is becoming more and more complex, defense, metallurgy, food, chemical, pharmaceutical and nuclear industries such as high grade, high pure demand highlights and low carbon economy globalization; separation machinery industry attracted more and more attention, for disc separator, the number of production and the application of the scale has been far more than other types of continuous centrifuge combined, the normal work process, machine structure safety and processing stability is particularly important; in view of the current disc separator increasing speed, the system structure is becoming more and more complex, the classical elasticity theory can not meet the requirement of design problems; based on the LX-460 type disc separator for latex the object of study, in order to improve the safety of structure, reduce the stress level as the goal, combined with the finite element analysis and theoretical calculation, the main structure of Netlon In order to improve the efficiency of separation and the performance of the whole machine, reduce the labor intensity and increase the production capacity.
In this paper, the main work of the study on the structure of disc separator and the results of the study are as follows:
(1) study on the stress characteristics of the drum structure
Study on the drum working speed idling characteristic stress of structure state and work state of two conditions, determine the finite element analysis of the restriction conditions, establish the calculation model and comparison of drum stress distribution under two working conditions; the geometric path of drum thread, the discharge of high local stress area; change the working speed of the condition of structure stress variation and the working speed of the drum; establish contact model, finite element contact analysis, contact analysis, effects of different stiffness coefficient Knormal variation speed and convergence curves of contact model, determine the optimal stiffness. The results show that: the overall structure the stress level of the uneven distribution of sediment area of the drum, the drum wall, the thread position of the local stress level is very high, should by means of structural optimization, considering the reduced structural stress concentration To improve the structure strength, structure light weight and other aspects of design.
(2) study on the stress characteristics of helical gear
The construction parameters of spiral gear solid model, aiming at the particularity of the space point contact type, the establishment of meshing finite element model for three-dimensional contact analysis, compare the different number of teeth, the contact stress changes; Determination of thermal conductivity, heat transfer coefficient, temperature field constraints, considering the gear box for heating bonding, tooth wear, pitting failure effect, the temperature as thermal load, analyze the thermoelastic coupling of coupling field load distribution. The results show that: the different number of teeth in contact, stress distribution of tooth surface contact is basically the same, point contact conditions, the coupling field of high stress level, tooth the heated gear wear speed, greatly affects the meshing efficiency, pulsating cyclic alternating stress caused by gear, bearing vibration, resulting in drum imbalance, caused serious consequences. We should optimize the structure. To reduce the heat of the closed gear box and the state of the gear load, so as to improve the transmission efficiency.
(3) evaluation of the results of finite element calculation and strength checking
The torque, torque theory analysis of rotary drum wall and the strength of the edge effect area, theoretical analysis of helical gear tooth contact fatigue strength and bending fatigue strength, comparing the results of theoretical calculation and finite element analysis results, the correctness of the calculation method of analysis and validation of finite element modeling, combined with the principle and stability the structural strength assessment criteria, evaluate the strength and safety check of structure strength. The results indicate that the drum by finite element method and the existing method, the stress distribution of helical gear close and the relative error was less than 20%, verify the correctness of the analysis method of finite element modeling, under normal circumstances, the theory method stress calculation and structure design is conservative. By comparing the results, analysis of structure stress value is slightly greater than the theoretical value of finite element method, and the reality that, by using the finite element method The structure of the separator is more advanced, the strength of the finite element is checked and the strength of the structure meets the requirements.
(4) structural multi-objective drive optimization design
Drive optimization technique using multi-objective ANSYS in Workbench environment (GDO), driver design optimization analysis of disc separator drum lock ring and spiral gear for multi target, from safety, economy point of view, combined with the optimization objective function sensitivity analysis and parameter response analysis, optimizing geometric parameters and performance parameters, finite element analysis and structure design, studied the structure function before and after optimization, the optimal structure parameter optimization. The optimized structure shows that the stress distribution is relatively uniform, the stress concentration decreases, the maximum equivalent stress decreased significantly, reduce material consumption, the comprehensive performance of the structure can be improved, and has a certain value to the dish separator structure optimization and improve the reliability.

【学位授予单位】：广东海洋大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TH132.422;TQ051.8

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