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类型 基础研究 预答辩日期 2018-01-08
开始(开题)日期 2014-01-03 论文结束日期 2017-10-12
地点 土木馆203 论文选题来源 国家自然科学基金项目     论文字数 11.9 (万字)
题目 粘弹性阻尼器微振减振机理及试验研究
主题词 粘弹性阻尼器,微振减振机理,性能试验,力学模型,;隔减振平台
摘要 微振动问题广泛存在于高科技工业厂房、精密实验室、航天器等结构中,并严重影响其内部精密设备的运行。其中,空间微振动会严重影响高分辨率相机的成像品质、降低制导武器的命中精度、缩短精密仪器及航天器等的使用寿命,严重阻碍高精尖科技的发展。因此,进行微振动抑制研究是一项重要而紧迫的课题。目前,对于微振动抑制的研究,提出了各种技术手段,取得了一些成果。但是也存在一些问题,例如附加能源供应、电磁场干扰、时滞效应等,可能造成控制效果不稳定,并且这些问题在空间微振动控制上表现更加突出。同时目前提出的隔减振装置也存在阻尼小、隔振效率低等问题。因此,有必要对微振动控制进行进一步研究,提出更加简便、有效、稳定性好的控制手段。粘弹性材料及阻尼器因其耗能能力强、性能可靠、无需附加能源、制造简便、造价低廉等优点已广泛应用于航空航天、机械工程、土木结构、车辆工程及军事设施等领域振动控制中。科研工作者针对粘弹性阻尼器抑制普通振动进行了大量研究,其主要是关于粘弹性阻尼器性能研究、力学模型研究和减振结构的研究。但是,对于将粘弹性材料应用于微振动抑制缺乏相应研究,特别是微振动下粘弹性材料的减振机理、力学性能和力学模型等需要深入的研究。 本文以利用粘弹性隔减振装置进行微振动抑制为最终目的,围绕其开展了粘弹性材料的微振减振机理、粘弹性阻尼器微振动条件下相应力学性能及力学模型的研究。基于以上研究,设计了粘弹性微振动隔减振平台,并利用该平台对航天器飞轮系统进行隔减振分析。建立了飞轮隔减振系统的耦合动力学模型,并对隔减振系统进行了动力响应数值模拟分析以及隔减振效果分析。本文的研究旨在对推动微振动抑制技术及粘弹性阻尼减振技术的发展。以下是本文研究的主要内容及结论: (1)对基体橡胶分子链结构进行了抽象和等效分析,分别研究了基体橡胶中交联网络链和自由分子链的结构特性对粘弹性材料性能的影响。研究了交联网络链中链长不均匀性和链运动约束效应对粘弹性材料弹性恢复性能的影响;研究了自由网络链中链长不均匀性效应对粘弹性材料耗能的影响。结果表明,基体橡胶的力学特性主要与其分子链结构特性有关,且与位移幅值无关,说明将粘弹性材料应用于微振动抑制是可行的。 (2)研究了填料体系与基体橡胶作用、填料与填料间相互作用对粘弹性材料力学性能及耗能性能的影响,分别推导了考虑填料与基体相互作用、填料网络演化产生的耗能表达式。结果表明,填料的结构及体积分数对粘弹性材料耗能能力有较大影响。 (3)基于对粘弹性材料微观结构与其性能关系的研究,结合微振动特征,研究了粘弹性材料微振动减振机理。结果表明,微振动条件下,粘弹性材料的耗能主要来源于基体橡胶本身以及其与填料间的相互作用。该研究为微振动条件下高耗能粘弹性材料的研制提供了理论指导。 (4)基于粘弹性材料微振抑制机理的研究成果,研制了适用于微振动抑制粘弹性材料,并制作成相应的粘弹性阻尼器试件。在微振动条件下,对所研制的粘弹性阻尼器试件在不同环境温度、不同激励频率、不同位移幅值下进行了力学性能试验研究,分析了温度、频率和幅值对粘弹性阻尼器力学性能的影响规律。结果表明,所研制的粘弹性阻尼器在微振动条件下有较好的耗能能力,并且温度和频率对其力学性能有较大影响,而幅值的影响则较小。 (5)基于粘弹性材料微振减振机理和粘弹性阻尼器的力学性能试验研究,首先提出了粘弹性阻尼器的微观链结构模型。结合温频等效原理,最终提出了考虑温度影响的修正微观链结构模型,并对试验结果和模型计算结果进行了对比分析,发现二者吻合较好。表明所提出的力学模型能够综合反映温度、频率对粘弹性材料力学性能的影响。同时,修正微观链结构模型反映了材料的动态力学性能与材料微观结构的关系,且模型参数同粘弹性材料的微观结构相关,具有明确的物理意义。 (6)综合分析了航天器部件隔减振要求及飞轮结构特点,提出将粘弹性隔减振装置用于飞轮系统隔减振的方案。分析了飞轮结构的动力特性,以及其产生微振扰动的影响因素,并在此基础上确定飞轮系统微振动激励源模型。结果表明,飞轮系统产生并传递到航天器结构的微振扰动与飞轮的结构密切相关,且受飞轮结构模态的影响较大。采用高耗能粘弹性材料设计了飞轮系统微振动隔减振平台,并对平台的关键部件粘弹性隔减振单元进行研究。研究发现,由于粘弹性材料的频率依赖性,该单元的隔减振效果要优于普通隔减振装置。建立了飞轮微振动隔减振系统的耦合动力学模型,并在不同激励下分析了隔减振系统的动力响应和隔减振效果。结果表明,所设计的隔减振装置能够有效地抑制飞轮产生微振扰动对航天器结构的影响,并且对不同的激励均有较好的抑制效果。 本文的创新之处在于: (1)开展了粘弹性材料的微振抑制机理研究,在微观层面研究了粘弹性材料基体分子结构、添加剂和填料对粘弹性材料耗能能力的影响。从理论上研究粘弹性材料的耗能机理,为高性能粘弹性材料的研制及应用奠定了基础。 (2)进行了微振动条件下粘弹性阻尼器力学性能试验研究,特别是研究了环境温度对阻尼器力学性能的影响;全面研究了微振动条件下环境温度、激励频率和位移幅值对粘弹性阻尼器力学性能的影响规律;基于粘弹性材料微振减振机理及性能试验研究,提出了能够同时描述温度和频率影响的修正微观链结构模型。 (3)利用高耗能粘弹性材料设计了相应的微振动隔减振平台,以航天器飞轮系统作为隔减振对象,建立了飞轮隔减振系统动力学模型,分析了系统的动力响应,并评价了隔减振效果。
英文题目 MICRO-VIBRATION DAMPING MECHANISM AND EXPERIMENTAL STUDY ON THE VISCOELASTIC DAMPER
英文主题词 Viscoelastic damper,Micro-vibration damping mechanism,Performance test,Mechanical model,Isolation and mitigation platform
英文摘要 Micro-vibration exists extensively within high-tech industrial plants, precision laboratories, spacecraft and other structures, and the operation of the precision equipment will be seriously affected. Space micro-vibration will seriously affect the imaging quality of high resolution camera, reduce the hit accuracy of the guided weapon, shorten the service life of the precision instruments and spacecraft, will seriously hinder the development of advanced science and technology. Therefore, the research of micro-vibration suppression is an important and urgent task. At present, for the research on micro-vibration suppression, rich achievements have been gained and various technical means have been proposed. However, there are still some problems, such as additional energy supplies, the interference of magnetic field, time delay effect, which may lead the control system become unstable. These problems will become more prominent on the space micro-vibration control performance. Therefore, it is necessary to further study the micro-vibration control, and propose the more simple, effective and stable vibration control method. Viscoelastic materials and dampers are widely used for vibration controlling in the fields of aerospace, mechanical engineering, civil engineering, vehicle engineering and military facilities owing to their advantages of strong energy consumption, reliable performance, no additional energy, easy manufacture and low cost. A lot of research on viscoelastic dampers for ordinary vibration suppression have been conducted by researchers. These studies are focused on the performance of viscoelastic dampers, mechanical model of the damper and the controlled structures. However, Studies on the application of VE dampers under micro-vibration conditions are rare and have not been reported,especially the vibration mechanism and mechanical properties of viscoelastic materials under micro-vibration need to be further studied. This paper is aimed at using viscoelastic dampers to suppress micro-vibration. Then, the theoretical and experimental study on micro-vibration damping mechanism of viscoelastic material, mechanical properties and mechanical model of viscoelastic dampers under micro-vibration conditions were carried out. Based on the above studies, a viscoelastic micro-vibration isolation and mitigation platform was designed and was introduced to isolate micro-vibration caused by the spacecraft flywheel. Then, the dynamics model of the coupling system that consists of the platform with flywheel was established. Finally, the numerical simulation analysis of dynamic response and isolation and mitigation effect of the system were analyzed and discussed. The research of this paper is of great significance to promote the development of micro-vibration suppression technology and viscoelastic damping technology. The following is the main content and conclusions of this study: (1)The molecular chain structure of the matrix rubber was abstractly analyzed. The effects of the structure of the crosslinked network chain and the structure of the free molecular chain on the properties of the viscoelastic material were investigated. The influence of chain length heterogeneity and chain motion constraint on the elastic recovery properties of viscoelastic materials in cross-linked network chains was studied. The effect of chain length heterogeneity of free molecular chain on the energy dissipation of viscoelastic materials was also studied. The results show that the mechanical properties of the matrix rubber are mainly related to the molecular chain structure characteristics, but has no relation with the displacement amplitude, this indicates that the application of viscoelastic materials to micro vibration suppression is feasible. (2)The effects of the filler-filler interaction and filler-rubber interaction on the mechanical properties and energy dissipation of the viscoelastic materials were studied. The energy dissipation caused by the filler-rubber interaction and the evolution of filler-network were deduced respectively. The results show that the filler structure and volume fraction have a great influence on the energy consumption capacity of viscoelastic materials. (3)Based on the study of the relationship between microstructure and properties of viscoelastic materials, the micro-vibration damping mechanism of viscoelastic materials was studied by combining the characteristics of micro vibration. The results show that the energy consumption of viscoelastic materials is mainly due to the filler-rubber interaction and the matrix rubber under micro-vibration conditions. This study provides theoretical guidance for the development of high energy consumption viscoelastic micro-vibration suppression materials. (4)Based on the achievements of study on micro-vibration damping mechanism of viscoelastic materials, micro-vibration suppression viscoelastic materials were developed and made into corresponding viscoelastic dampers. Under the micro-vibration conditions, the experimental study on the developed viscoelastic dampers were conducted at different temperatures, frequencies and amplitudes. Then, the effects of temperature, frequency and amplitude on the viscoelastic dampers were analyzed. The results show that the viscoelastic dampers have better energy dissipation capacity under micro vibration condition, and the temperature and frequency have a great influence on the mechanical properties, while the influence of amplitude is small. (5)Based on the micro-vibration damping mechanism of viscoelastic materials and the mechanical properties tests of viscoelastic micro-vibration dampers, the microscopic chain structure model of viscoelastic dampers is proposed. By combining with temperature-frequency equivalent principle,the modified microscopic chain model are finally proposed. The results of the tests and the model were compared and it can be found that the two are in good agreement. It is shown that the proposed mechanical model can comprehensively reflect the influence of temperature and frequency on the mechanical properties of viscoelastic materials. At the same time, the microscopic chain model can reflects the relationship between the dynamic mechanical properties and the microstructure of the material. The model parameters are related to the microstructure of the viscoelastic material and have a clear physical meaning. (6)Based on the analysis of the characteristics of flywheel vibration system and flywheel structure, the scheme of using the viscoelastic vibration isolation device for the vibration reduction of the flywheel system was put forward. The dynamic characteristics of the flywheel system are analyzed, and the influencing factors of the micro-vibration disturbance of the flywheel system are studied. Then, the micro-vibration excitation model of the flywheel system is established. The results show that the micro disturbance caused and transmitted to spacecraft by the flywheel system is closely related to the structure of the flywheel itself, and it is influenced by the modal of the flywheel. The micro-vibration isolation and mitigation platform for flywheel system was designed by using high energy consuming viscoelastic material. The viscoelastic isolation and mitigation element as key components of the platform was studied. It is found that the damping effect of the isolation and mitigation element is better than that of the ordinary vibration isolation device due to the frequency dependence of the viscoelastic material. The coupling dynamic model of the flywheel micro-vibration isolation and mitigation system is established, and the dynamic response and the vibration reduction effect of the isolation and mitigation system are analyzed under different excitation. The results show that the designed isolation and mitigation device can effectively suppress the transmission of micro disturbance from the flywheel to the spacecraft structure, and it has a good isolation effect at the different excitations. The innovations of this paper are of the followings: (1)The micro-vibration damping mechanism of viscoelastic materials were studied. The effects of molecular structure, additive effect and filler on the energy dissipation of viscoelastic materials were studied at the microscopic level. The energy dissipation mechanism of viscoelastic materials is studied theoretically, which provides the theoretical basis for the development and application of high performance viscoelastic materials. (2)The mechanical properties of viscoelastic dampers under micro vibration are experimentally studied, the effect of temperature on the mechanical properties of dampers are especially considered. The influence of ambient temperature, excitation frequency and displacement amplitude on the mechanical properties of viscoelastic dampers under micro vibration condition is studied. Based on the damping mechanism and performance test of viscoelastic materials, a modified microscopic chain structure model which can describe the influence of temperature and frequency on the mechanical properties of viscoelastic dampers is proposed. (3)The micro-vibration isolation and mitigation platform is designed by using the high energy consumption viscoelastic material. The flywheel system is used as the vibration isolation object, and the flywheel vibration isolation and mitigation system is established. The dynamic response and the vibration reduction effect are analyzed.
学术讨论
主办单位时间地点报告人报告主题
土木工程学院 2013.12.13 逸夫馆1501会议室 邓露 车桥耦合振动的研究及其应用
东南大学 2016.06.06 大礼堂 谢礼立 建设可康复的城镇防灾体系
土木工程学院 2017.04.18 逸夫馆1501会议室 Yixiang Gan Mechanics of Compacted Granular Materials:
NC State University 2015.07.25 EB Ⅲ 2168 徐超 Introduction of Seismic Matematerial
防灾教研室 2014.09.04 土木馆203 徐超 粘弹性材料减振机理研究
防灾教研室 2014.12.05 逸夫馆607 徐超 粘弹性阻尼器试验研究
防灾教研室 2017.03.02 土木馆203 徐超 粘弹性微振隔减振平台研究
东南大学 2016.10.25 春晖堂 崔俊芝 土木工程中的计算科学和技术:若干前沿问题
     
学术会议
会议名称时间地点本人报告本人报告题目
Symposium in Structural Engineering and Mechanics 2015.10.07 Raleigh Study on VE micro-vibration damper
第九届全国防震减灾工程学术研讨会 2016.10.28 合肥 粘弹性阻尼器微振力学模型及应用研究
     
代表作
论文名称
Modeling and experimentation of a viscoelastic microvibration damper based on a chain network model
Experimental and numerical study on dynamic properties of viscoelastic microvibration damper consid
Equivalent fractional kelvin model and experimental study on viscoelastic damper
 
答辩委员会组成信息
姓名职称导师类别工作单位是否主席备注
邹鸿生 正高 教授 博导 南京航空航天大学
朱召泉 正高 教授 博导 河海大学
李今保 正高 研究员级高工 硕导 江苏东南特种技术工程有限公司
黄东升 正高 教授 博导 南京林业大学
王曙光 正高 教授 博导 南京工业大学
      
答辩秘书信息
姓名职称工作单位备注
黄兴淮 其他 讲师 东南大学