基于修正模态应变能法的硬涂层薄板结构阻尼预估及优化

发布时间：2018-08-05 11:15

【摘要】：硬涂层是指由金属基、陶瓷基或两者的混合制成的涂层材料。近年来的研究发现,涂敷硬涂层的结构系统阻尼系数增加、共振应力降低,即硬涂层具有阻尼减振的效果。预测硬涂层复合结构的阻尼性能是硬涂层阻尼减振研究中的一个关键内容。模态应变能法是预测复合结构阻尼性能的一种经典方法。但经典的模态应变能法却无法直接应用于硬涂层复合结构的阻尼性能预估中。本文在考虑硬涂层材料中小阻尼特点以及修正经典模态应变能法计算误差的前提下,提出了一种适用于硬涂层复合结构阻尼性能预估的新方法,并开展了涂敷位置优化设计研究,具体研究内容体现在以下4方面：首先,阐述了模态应变能法的基本理论。给出了求解整体模态应变能以及单元模态应变能的理论公式。用悬臂钛板结构予以举例例证,应用ANSYS和Matlab分别计算了固支薄板结构前6阶的固有频率、整体模态应变能和单元模态应变能分布,叙述了求解模态应变能的具体流程及主要命令,并对比两者的计算结果。然后,介绍了应用经典模态应变能法预估硬涂层复合结构阻尼的过程。在改善经典模态应变能法计算误差的背景下,提出了两种修正模态应变能法用于硬涂层复合结构阻尼性能的预估,推导了修正模态应变能法的原理性公式,描述了预估硬涂层复合结构阻尼性能的计算流程。并以一个涂敷Mg-AL硬涂层的悬臂薄板为例进行了实例研究。再则,讨论了硬涂层材料杨氏模量、损耗因子和涂层厚度对结构系统阻尼性能的影响。分别探究了单一因素和两两组合因素对阻尼性能的影响规律。结果发现增大硬涂层的杨氏模量、损耗因子及厚度均可以提高复合结构的阻尼性能。最后,针对硬涂层薄板结构完成了局部涂敷的阻尼优化设计。局部涂敷硬涂层位置的选择是依据模态应变能法计算获得的。讨论了抑制单一阶次和多阶次振动的阻尼优化情况,并探究了局部涂敷面积对复合结构阻尼性能的影响。设计实施了多组实验,很好地验证了用模态应变能法进行阻尼优化设计的相关结论。本文的研究成果可为硬涂层材料制备及阻尼减振设计提供参考,也可为硬涂层减振技术在动力装备薄壳结构中的应用提供支持。
[Abstract]:A hard coating is a coating material made of metal, ceramic, or a mixture of the two. In recent years, it has been found that the damping coefficient of the structure coated with hard coating increases and the resonance stress decreases, that is, the hard coating has the effect of damping and damping vibration. Predicting the damping performance of hard coating composite structure is a key content in the research of hard coating damping and vibration absorption. Modal strain energy method is a classical method for predicting damping performance of composite structures. However, the classical modal strain energy method can not be directly applied to the damping performance prediction of hard coated composite structures. In this paper, a new method for predicting damping performance of hard coated composite structures is proposed on the premise of considering the characteristics of medium and small damping of hard coating materials and correcting the calculation error of classical modal strain energy method. The optimum design of coating position is studied in the following four aspects: firstly, the basic theory of modal strain energy method is expounded. The theoretical formulas for solving the global modal strain energy and the element modal strain energy are given. With the example of cantilever titanium plate structure, ANSYS and Matlab are used to calculate the first 6 natural frequencies, the global modal strain energy and the element modal strain energy distribution of the clamped thin plate structure, respectively. The concrete flow and main commands of solving modal strain energy are described, and the calculation results are compared. Then, the process of estimating the damping of hard coating composite structure by classical mode strain energy method is introduced. Under the background of improving the calculation error of classical modal strain energy method, two modified mode strain energy methods are proposed to predict the damping performance of hard-coated composite structures. The principle formula of modified mode strain energy method is derived. The calculation flow of damping performance of hard coating composite structure is described. A cantilever plate coated with Mg-AL hard coating is taken as an example. Furthermore, the effects of Young's modulus, loss factor and coating thickness on the damping properties of hard coating materials are discussed. The influence of single factor and couple factor on damping performance is studied respectively. The results show that the damping properties of the composite structure can be improved by increasing the Young's modulus, loss factor and thickness of the hard coating. Finally, the damping optimization design of hard coated thin plate structure is completed. The location of hard coating is calculated by modal strain energy method. The damping optimization of single and multi-order vibration suppression is discussed, and the effect of local coating area on the damping performance of composite structures is discussed. Many experiments have been carried out to verify the conclusion that the modal strain energy method is used to optimize the damping design. The research results in this paper can be used as reference for the preparation of hard coating materials and the design of damping vibration, and also for the application of hard coating damping 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】：TB535.1

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