硬涂层梁及板复合结构动力学建模与分析

发布时间：2018-06-08 02:36

本文选题：硬涂层梁 + 硬涂层板　；参考：《东北大学》2014年硕士论文

【摘要】：硬涂层是由金属基和陶瓷基做成的涂层材料,主要应用于结构件的热障、抗摩擦、抗腐蚀等。最近的研究发现,硬涂层还具有阻尼减振效果,且特别适用于对动力装备中的薄壳结构(例如叶片、圆柱壳体等)进行减振。为了有效实施硬涂层阻尼减振,需要创建硬涂层复合结构的动力学模型来分析硬涂层的减振机理。但是,作为一种新兴的减振技术,这方面的研究还很不充分。对硬涂层阻尼减振机理认识不清已严重限制了硬涂层阻尼减振技术的发展。本文以涂敷硬涂层的梁及薄板为研究对象,在科学引入硬涂层材料力学特点的基础上,研究硬涂层复合结构动力学建模的方法,具体研究内容体现在如下四方面：首先,基于复合梁理论对基础激励作用下硬涂层悬臂梁复合结构进行振动特性分析。利用复模量理论,将硬涂层的参数引入到结构动力学方程中,建立了基础激励作用下该复合结构的解析分析模型,并用有限元法验证了分析模型的正确性。继而,基于所创建的模型,研究了硬涂层杨氏模量、损耗因子、厚度等参数对复合梁的动力学特性的影响规律。然后,基于复合板理论对基础激励作用下硬涂层悬臂板复合结构进行振动特性分析。利用复模量理论来引入硬涂层的参数,利用双向梁函数组合法建立了基础激励作用下该复合件的拉格朗日方程,得到了求解固有特性和振动响应的解析表达式。用有限元法验证了分析模型的正确性,在此基础上,用该解析模型分析了硬涂层杨氏模量、损耗因子、厚度等参数对复合板的动力学特性的影响规律。再则,硬涂层材料的力学特性参数会随着激励幅度的不同而发生改变,即表现为应变依赖性。硬涂层材料的非线性致使硬涂层复合结构也表现出非线性的力学特点。这里在考虑硬涂层材料应变依赖性的前提下,提出采用迭代有限元来分析硬涂层复合结构动力学特性的方法,确定了合理的分析流程。然后分别以硬涂层梁和硬涂层板为实例进行了分析,并用实验校验了分析的正确性。最后,同样考虑硬涂层材料的应变依赖性,对硬涂层悬臂梁结构进行解析分析,创建了该复合梁结构的非线性动力学方程。进一步,提出利用逐步迭代法和Newton-Raphson法来求解硬涂层复合梁的固有频率和定频响应的方法以及计算流程。实例分析表明,用所提出的方法获得的固有频率和定频响应值与有限元计算基本一致,从而证明了该解析分析模型的正确性。本文可为在硬涂层减振研究中,选择与制备硬涂层材料提供参考,为进一步深入研究硬涂层的阻尼减振机理提供参考,也可为硬涂层减振技术在动力装备薄壳结构上推广应用提供支持。
[Abstract]:Hard coating is a coating material made of metal and ceramic. It is mainly used in thermal barrier, friction resistance and corrosion resistance of structural parts. Recent studies have found that the hard coating also has damping effect and is especially suitable for vibration absorption of thin shell structures (such as blades cylindrical shells etc.) in power equipment. In order to effectively implement the damping and damping of hard coatings, it is necessary to establish a dynamic model of hard coating composite structure to analyze the mechanism of hard coating damping. However, as a new vibration absorption technology, the research in this area is not enough. The development of hard coating damping technology has been seriously restricted by unclear understanding of the mechanism of hard coating damping and vibration absorption. On the basis of introducing the mechanical characteristics of hard coating materials scientifically, the dynamic modeling method of hard coating composite structure is studied in this paper. The specific research contents are as follows: firstly, Based on the theory of composite beam, the vibration characteristics of hard-coated cantilever composite structure under foundation excitation are analyzed. Based on the complex modulus theory, the parameters of the hard coating are introduced into the structural dynamic equation, and the analytical analysis model of the composite structure under the foundation excitation is established, and the correctness of the analytical model is verified by the finite element method. Then, based on the model, the influence of the parameters such as Young's modulus, loss factor and thickness of hard coating on the dynamic characteristics of composite beam is studied. Then, based on the theory of composite plate, the vibration characteristics of cantilever composite structure with hard coating under the action of foundation excitation are analyzed. Using the complex modulus theory to introduce the parameters of the hard coating, the Lagrange equation of the composite subjected to foundation excitation is established by using the bidirectional beam function combination method, and the analytical expressions for solving the natural characteristics and vibration response are obtained. The validity of the analytical model is verified by finite element method. On the basis of the model, the influence of the parameters such as Young's modulus, loss factor and thickness of hard coating on the dynamic characteristics of the composite plate is analyzed. Furthermore, the mechanical properties of the hard coating materials change with the excitation amplitude, that is, the mechanical properties of the hard coating materials are strain dependent. Due to the nonlinearity of hard coating materials, the composite structure of hard coating also shows nonlinear mechanical characteristics. In this paper, an iterative finite element method is proposed to analyze the dynamic characteristics of hard coating composite structures considering the strain dependence of hard coating materials, and the reasonable analysis flow is determined. Then, the examples of hard coated beam and hard coated plate are analyzed, and the correctness of the analysis is verified by experiments. Finally, considering the strain dependence of the hard coating material, the nonlinear dynamic equation of the composite beam structure is established by analytically analyzing the cantilever structure with hard coating. Furthermore, a method for calculating the natural frequency and fixed frequency response of a hard-coated composite beam by using the step-by-step iterative method and the Newton-Raphson method is presented. An example shows that the natural frequency and fixed frequency response obtained by the proposed method are in good agreement with the finite element method, which proves the correctness of the analytical model. This paper can provide a reference for the selection and preparation of hard coating materials in the study of hard coating vibration absorption, and for the further study of damping mechanism of hard coating. It can also provide support for the popularization and application of hard coating vibration absorption technology in the thin shell structure of power equipment.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB535

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