煤炭采样车工作装置有限元分析与优化设计

发布时间：2018-05-03 21:27

本文选题：煤炭采样车 + 五自由度　；参考：《西安建筑科技大学》2017年硕士论文

【摘要】：随着社会发展,机械化采样方式替代人工采样方式实现了更加快速、高效的采样。五自由度关节式煤炭采样车在工作空间中具有很好的避障、适应性强和多位姿等优点,在煤炭采样领域有很好的应用前景。以往针对煤炭采样车工作装置进行强度分析时,由于将结构件分开计算而产生了边界条件和载荷不确定所引入的误差,导致了计算结果不够精确。由于工程机械普遍存在强度、刚度盈余、自重过大等缺点,未能最大程度发挥材料性能,因此煤炭采样车工作装置的结构强度和机械臂截面尺寸直接影响整机的可靠性和经济性。据此,本文结合实际项目,提出了一种五自由度关节式煤炭采样工作装置的设计方案,并对工作装置进行了机构尺寸设计、工作空间仿真分析、集成有限元分析和结构优化设计,论文主要工作有:首先,简明介绍了在现代煤炭交易中,煤炭采样环节的效率直接影响整体煤质检测时间,因此迫切需要以自动化设备替代人工煤炭采样。在明确课题研究的背景下,简单介绍了煤炭采样车的整机组成、机构特点和工作原理等。同时,根据工作要求提出了关节式煤炭采样车工作装置初步设计方案,借助于Matlab强大数学计算功能和优化函数对工作装置的机构尺寸进行了优化与求解。其次,用SolidWorks建立工作装置三维模型,基于SolidWorks Motion运动仿真得到工作装置的工作空间及运动特性。在建立工作装置集成有限元模型时,将复杂的实体接触问题通过约束方程理论转化为在ANSYS中建立刚性区来求解。将工作装置三维模型导入ANSYS中,在对煤炭采样车工作装置三种典型工况分析的基础上,采用节点耦合和生成MPC184单元的方法模拟了销轴连接,采用Link8杆单元模拟了油缸连接,建立了工作装置整体集成有限元模型,并进行了强度、刚度和模态分析。最后,采用了一种针对CAD软件模型导入ANSYS经典界面中参数化处理的方法,依此建立了工作装置的整体参数化模型。以工作装置整体的总体积最小作为目标函数,选取大臂、中臂和小臂臂厚尺寸作为优化参数,相应的定义了9个设计变量,提取优化模型的静力分析结果中最大应力和最大位移作为状态变量,对模型进行优化设计。本文主要以最优化理论为基础,以集成有限元分析为方法,对提出的五自由度关节式煤炭采样车工作装置进行了基于Matlab的机构尺寸的优化和基于ANSYS的结构尺寸的优化,最后实现工程机械轻量化设计的目的,为同类产品的优化与改进提供参考价值,为解决实际工程问题提供了重要的理论依据。
[Abstract]:With the development of society, mechanized sampling instead of manual sampling realizes faster and more efficient sampling. The five-degree-of-freedom joint coal sampling vehicle has the advantages of good obstacle avoidance, strong adaptability and multi-pose in the workspace, so it has a good application prospect in the field of coal sampling. In the past, when analyzing the strength of the working device of the coal sampling vehicle, the error caused by the uncertainty of the boundary condition and the load caused by the separate calculation of the structure resulted in the inaccuracy of the calculation results. Because of the shortcomings of strength, stiffness surplus and overweight of construction machinery, it is unable to give full play to the material properties. Therefore, the reliability and economy of the whole machine are directly affected by the structural strength of the working device and the section size of the arm of the coal sampling vehicle. On the basis of this, this paper puts forward a design scheme of the coal sampling working device with five degrees of freedom based on the actual project, and carries on the mechanism dimension design and the workspace simulation analysis to the work device. Integration of finite element analysis and structural optimization design, the main work of this paper is as follows: firstly, the efficiency of coal sampling in modern coal trading has a direct impact on the overall coal quality detection time. Therefore, there is an urgent need to replace artificial coal sampling with automation equipment. In the background of the research, this paper introduces the whole machine, mechanism and working principle of the coal sampling vehicle. At the same time, according to the requirements of the work, the preliminary design scheme of the working device of the joint coal sampling vehicle is put forward, and the size of the working device is optimized and solved with the help of the powerful mathematical calculation function and the optimization function of Matlab. Secondly, the 3D model of the working device is built by SolidWorks, and the workspace and motion characteristics of the working device are obtained based on the motion simulation of SolidWorks Motion. In the process of establishing the integrated finite element model of the working device, the complex solid contact problem is transformed into a rigid zone in ANSYS by the theory of constraint equation. The three-dimensional model of the working device is introduced into ANSYS. Based on the analysis of three typical working conditions of the working device of the coal sampling vehicle, the pin shaft connection is simulated by the method of node coupling and MPC184 unit generation, and the oil cylinder connection is simulated by the Link8 bar element. The integral finite element model of the working device is established, and the strength, stiffness and modal analysis are carried out. Finally, a parameterization method is used to import the CAD software model into the classical interface of ANSYS, and the whole parameterized model of the working device is established. Taking the minimum of the total volume of the working device as the objective function and selecting the thick size of the arm, middle arm and forearm as the optimization parameters, nine design variables are defined accordingly. The maximum stress and the maximum displacement are extracted from the static analysis results of the optimization model as state variables, and the optimization design of the model is carried out. Based on the optimization theory and the method of integrated finite element analysis, the mechanism dimension optimization based on Matlab and the structure dimension optimization based on ANSYS are carried out in this paper. Finally, the aim of lightweight design of construction machinery is realized, which provides a reference value for the optimization and improvement of similar products, and provides an important theoretical basis for solving practical engineering problems.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD67;TQ533

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