發(fā)布時間：2018-07-23 09:12

【摘要】：動力伺服刀架是車削加工中心及車銑復合加工中心的核心功能部件,其可靠性、精度和剛度等指標在很大程度上決定了整臺機床的性能。而密封結構又是動力伺服刀架中的關鍵部件,它的設計水平直接決定整個動力伺服刀架的性能。在工作中,密封結構的幾何尺寸、載荷、材料屬性等均具有一定的隨機性,如果該結構設計不合理,就會導致其在工作過程中出現(xiàn)失效,進而造成損失。因此,對密封結構進行可靠性研究具有重要的理論意義和工程使用價值。 本文充分借鑒了國內外專家學者對密封結構受載后應力、應變分析結果,同時吸取結構可靠性靈敏度設計研究成果的基礎上,對動力伺服刀架中密封結構的可靠性問題進行了深入的研究。首先,建立密封結構的二維參數(shù)化模型。利用有限元仿真分析軟件直接建立簡化后的二維模型,同時對此過程進行參數(shù)化處理。這樣,只需更改設計參數(shù)可以實現(xiàn)密封模型的自動修改,增強了分析的靈活性,提高了設計效率；其次,引入神經(jīng)網(wǎng)絡理論,并將該技術應用于結構可靠性和可靠性靈敏度分析領域。充分利用神經(jīng)網(wǎng)絡的非線性映射、任意函數(shù)逼近等功能擬合出密封結構響應與隨機變量之間的函數(shù)關系式。根據(jù)神經(jīng)網(wǎng)絡擬合出的函數(shù)關系式,采用一次二階矩法和蒙特卡洛法計算出密封結構的可靠度和密封結構各隨機變量對可靠度的靈敏度；最后,對本文中單位互不相同基本隨機變量的可靠性靈敏度進行了無量綱化處理,并在Matlab軟件中繪制了可靠度對各基本隨機變量的均值靈敏度柱狀圖和方差靈敏度柱狀圖,定量、直觀地分析了可靠性對各個基本隨機變量的影響程度。為產(chǎn)品在設計階段提供了理論參考,有著積極地現(xiàn)實意義和理論價值。
[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.
【學位授予單位】：東北大學
【學位級別】：碩士
【學位授予年份】：2011
【分類號】：TH136;TB114.3

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