粘弹阻尼板减振动力学特性及其渐进拓扑优化

发布时间：2018-01-16 21:10

本文关键词：粘弹阻尼板减振动力学特性及其渐进拓扑优化　出处：《南昌航空大学》2015年硕士论文　论文类型：学位论文

【摘要】：粘弹性阻尼材料的高阻尼特性,使其能够高效耗损结构能量,常敷设于各类板件表面用以减小结构振动。然而,在诸如飞行器设计领域,由于对结构本身重量和动力学特性的严格要求,全面敷设粘弹性阻尼材料有悖于结构轻量化设计要求,需严格限制粘弹材料的用量。有鉴于此,本文着力于粘弹阻尼板结构的减振动力学优化研究,使结构轻量化的同时减振效果好。主要完成的工作如下:(1)从结构阻尼减振和结构优化设计的背景出发,阐述了粘弹阻尼减振结构动力学优化的研究意义,收集归纳了结构拓扑优化各类方法及其优缺点,并总结分析了拓扑优化在实际工程结构中的应用。(2)推导出粘弹板结构动力学有限元计算模型,研究了粘弹阻尼减振结构动力学拓扑优化理论。基于能量法,对粘弹结构进行了动力学建模并采用有限元法对其求解;在动力学优化理论的基础上,详细介绍了渐进结构拓扑优化方法。(3)初步探明了粘弹阻尼结构材料参数及结构参数对结构减振效果的影响,对粘弹结构的减振动力学特性进行了系统分析与优化。基于应变能理论,运用数值模拟方法,在对粘弹阻尼悬臂板结构振动特性研究的基础上,表征了粘弹性阻尼材料弹性模量、损耗因子及约束层与阻尼层的厚度比对结构减振特性的影响。研究表明:合理配置阻尼结构参数可获得理想的减振降噪效果。(4)提出了一种基于多模态复合阻尼比最大化的优化方法,对基于多模态振动响应复合的自由阻尼减振板结构进行了动力学拓扑优化研究。构建出以复合模态阻尼比最大为目标、以粘弹材料用量及频率变动最小为约束的优化模型,采用渐进法对该模型进行求解;通过绕单元阻尼比敏度均化技术有效解决了拓扑优化中的棋盘格问题;编程实现了任意四边形阻尼板渐进优化算法,并据此进行优化仿真;推出阻尼比体积密度以评析拓扑优化效能。结果表明,在阻尼板结构设计时若实现其多模态阻尼比最大,则能使板获得良好的减振效果。
[Abstract]:The high damping characteristics of viscoelastic damping materials enable them to efficiently consume structural energy and are often laid on the surface of various panels to reduce structural vibration. However, in the field of aircraft design, for example. Due to the strict requirements of the weight and dynamic characteristics of the structure itself, the comprehensive laying of viscoelastic damping materials is contrary to the structural lightweight design requirements, and the amount of viscoelastic materials should be strictly restricted. This paper focuses on the dynamic optimization of viscoelastic damping plate structure. The main work is as follows: 1) based on the background of structural damping and structural optimization design, the research significance of structural dynamic optimization with viscoelastic damping is expounded. The methods of structural topology optimization and their advantages and disadvantages are summarized, and the application of topology optimization in practical engineering structures is analyzed. The finite element model of viscoelastic plate structure dynamics is derived. The dynamic topology optimization theory of viscoelastic damping damping structure is studied. Based on the energy method, the dynamic model of viscoelastic structure is established and solved by finite element method. Based on the theory of dynamic optimization, the method of topology optimization of progressive structure is introduced in detail.) the influence of material parameters and structural parameters of viscoelastic damping structure on the damping effect of structure is preliminarily investigated. Based on the theory of strain energy and numerical simulation method, the vibration characteristics of viscoelastic damping cantilever plate structure are studied. The elastic modulus of viscoelastic damping materials was characterized. The effect of loss factor and thickness ratio of restraint layer to damping layer on vibration absorption characteristics of structure is studied. The results show that the optimal vibration and noise reduction effect can be obtained by reasonable configuration of damping structure parameters. An optimization method based on the maximization of multimodal composite damping ratio is proposed. The dynamic topology optimization of the free damping plate structure based on the multimodal vibration response composite is studied and the maximum damping ratio of the composite mode is constructed. The optimization model with minimum quantity and frequency change of viscoelastic material is solved by asymptotic method. The chessboard lattice problem in topology optimization is effectively solved by using the sensitivity homogenization technique of the damping ratio of the wound elements. The progressive optimization algorithm of any quadrilateral damping plate is realized by programming, and the optimization simulation is carried out according to the algorithm. The volume density of damping ratio is deduced to evaluate the effectiveness of topology optimization. The results show that the maximum multi-mode damping ratio of damping plate structure can make the plate obtain a good damping effect.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB535.1

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