动力伺服刀架密封结构可靠性灵敏度分析

发布时间：2018-07-23 09:12

【摘要】：动力伺服刀架是车削加工中心及车铣复合加工中心的核心功能部件,其可靠性、精度和刚度等指标在很大程度上决定了整台机床的性能。而密封结构又是动力伺服刀架中的关键部件,它的设计水平直接决定整个动力伺服刀架的性能。在工作中,密封结构的几何尺寸、载荷、材料属性等均具有一定的随机性,如果该结构设计不合理,就会导致其在工作过程中出现失效,进而造成损失。因此,对密封结构进行可靠性研究具有重要的理论意义和工程使用价值。本文充分借鉴了国内外专家学者对密封结构受载后应力、应变分析结果,同时吸取结构可靠性灵敏度设计研究成果的基础上,对动力伺服刀架中密封结构的可靠性问题进行了深入的研究。首先,建立密封结构的二维参数化模型。利用有限元仿真分析软件直接建立简化后的二维模型,同时对此过程进行参数化处理。这样,只需更改设计参数可以实现密封模型的自动修改,增强了分析的灵活性,提高了设计效率；其次,引入神经网络理论,并将该技术应用于结构可靠性和可靠性灵敏度分析领域。充分利用神经网络的非线性映射、任意函数逼近等功能拟合出密封结构响应与随机变量之间的函数关系式。根据神经网络拟合出的函数关系式,采用一次二阶矩法和蒙特卡洛法计算出密封结构的可靠度和密封结构各随机变量对可靠度的灵敏度；最后,对本文中单位互不相同基本随机变量的可靠性灵敏度进行了无量纲化处理,并在Matlab软件中绘制了可靠度对各基本随机变量的均值灵敏度柱状图和方差灵敏度柱状图,定量、直观地分析了可靠性对各个基本随机变量的影响程度。为产品在设计阶段提供了理论参考,有着积极地现实意义和理论价值。
[Abstract]:Dynamic servo tool holder is the core functional component of turning center and turn-milling complex machining center. Its reliability, precision and rigidity determine the performance of the whole machine tool to a great extent. The sealing structure is the key component in the power servo tool holder, and its design level directly determines the performance of the whole power servo tool holder. In the work, the geometric size, load and material properties of the sealing structure are all random. If the design of the structure is not reasonable, it will lead to the failure of the structure in the working process, which will cause losses. Therefore, it is of great theoretical significance and engineering value to study the reliability of sealing structure. In this paper, the results of stress and strain analysis of sealed structures after loading are fully used for reference, and the results of structural reliability sensitivity design are also absorbed. In this paper, the reliability of sealing structure in power servo tool holder is studied. Firstly, a two-dimensional parameterized model of sealing structure is established. The simplified two-dimensional model is directly established by using the finite element simulation analysis software, and the process is parameterized at the same time. In this way, only changing the design parameters can realize the automatic modification of the seal model, enhance the flexibility of analysis and improve the design efficiency. Secondly, the neural network theory is introduced. The technique is applied to structural reliability and reliability sensitivity analysis. The functions of nonlinear mapping and arbitrary function approximation of the neural network are fully used to fit the functional relationship between the response of the seal structure and the random variables. According to the function formula fitted by neural network, the reliability of seal structure and the sensitivity of each random variable of sealing structure to reliability are calculated by the first-order second-order moment method and Monte Carlo method. Finally, the second order moment method and Monte Carlo method are used to calculate the reliability of the sealing structure. In this paper, the reliability sensitivity of basic random variables with different units is dimensionless, and the mean sensitivity histogram and variance sensitivity histogram of reliability to each basic random variable are drawn in Matlab software. The influence of reliability on each basic random variable is analyzed intuitively. It provides a theoretical reference for the design stage of the product and has positive practical significance and theoretical value.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH136;TB114.3

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