基于粘弹性材料的约束阻尼型高衰减率隔振单元的研究

发布时间：2018-04-06 00:15

本文选题：粘弹性材料　切入点：约束阻尼　出处：《哈尔滨工业大学》2014年硕士论文

【摘要】：航天器搭载的高分辨率有效载荷及其自身指向稳定性对航天器的振动控制技术提出了更高的要求。对于频率成分较为丰富的扰振，若只为了降低共振峰放大倍数而提高阻尼系数，会使得高频段的振动传递率提高，隔振效果变差，，因此需要寻求合适的减振措施。本文以粘弹性材料的约束阻尼型结构为出发点，研究了粘弹性材料的阻尼原理及阻尼模型；基于ANSYS中的Prony级数方法，考虑了粘弹性材料的频变特性，分析了阻尼层的厚度、长度及模量对结构阻尼比的影响；重点研究了约束阻尼型隔振单元在振动控制中的减振性能，主要从以下几个方面展开研究：首先根据约束阻尼结构的剪切变形特点，建立了单元模型和位移函数，采用复模量频变模型，并结合粘弹性材料的WLF时温等效方程，理论上实现了粘弹性材料的温变、频变特性模拟，并采用QR阻尼法求解了含有粘弹性材料的复合悬臂梁的复特征值和阻尼比，与试验结果相对比，验证了本文建模求解方法的可行性。然后，根据隔振单元的初始结构，采用控制单一变量的方法，分析了阻尼层的各个参数对隔振单元阻尼比的影响规律；并通过对结果的分析，对其初始结构进行修正，确定了隔振单元的具体结构，建立三维模型，为有限元分析和动力学仿真做准备。最后建立了隔振单元的有限元模型和动力学仿真模型，进行了模态分析，得到其共振频率和模态振型，从而能够预测其振动耗能方式及能力大小；在ADAMS/Vibration模块中对隔振单元进行了X/Y/Z三个轴向方向的隔振性能分析，得到隔振单元对不同大小和方向的振动激励响应曲线和传递率，从而直观反映了隔振单元的主要隔振方向和隔振效果。本文的研究方法精确拟合了粘弹性材料的特性，为高衰减率隔振单元的研制提供了一种更有效的方法。
[Abstract]:The high resolution payload and its own directional stability of spacecraft put forward higher requirements for the vibration control technology of spacecraft.For the disturbance with rich frequency components, if the damping coefficient is increased only to reduce the amplification of the resonance peak, the vibration transmission rate in the high frequency band will be increased, and the isolation effect will become worse. Therefore, it is necessary to find appropriate damping measures.In this paper, the damping principle and damping model of viscoelastic materials are studied based on the constrained damping structure of viscoelastic materials. Based on the Prony series method in ANSYS, the frequency variation characteristics of viscoelastic materials are considered and the thickness of damping layer is analyzed.The effect of length and modulus on damping ratio of structure is studied, and the damping performance of constrained damping isolation unit in vibration control is mainly studied from the following aspects:Firstly, according to the shear deformation characteristics of constrained damping structure, the element model and displacement function are established. The complex modulus frequency variation model is adopted and the WLF time-temperature equivalent equation of viscoelastic material is used to realize the temperature variation of viscoelastic material theoretically.The complex eigenvalues and damping ratios of composite cantilever beams with viscoelastic materials are calculated by QR damping method. Compared with the experimental results, the feasibility of the proposed method is verified.Then, according to the initial structure of the isolation unit, the influence of the damping layer parameters on the damping ratio of the isolation unit is analyzed by using the method of controlling a single variable, and the initial structure is modified by the analysis of the results.The concrete structure of the vibration isolation element is determined and the three-dimensional model is established to prepare for finite element analysis and dynamic simulation.Finally, the finite element model and dynamic simulation model of the vibration isolation element are established, and the modal analysis is carried out, and the resonance frequency and modal mode are obtained, which can predict the energy dissipation mode and the capability of vibration.In the ADAMS/Vibration module, the vibration isolation performance of the three axial directions of X/Y/Z is analyzed, and the vibration excitation response curve and transmission rate of the isolation unit to different sizes and directions are obtained.Thus, the main isolation direction and vibration isolation effect of the isolation unit are intuitively reflected.In this paper, the characteristics of viscoelastic materials are fitted accurately, which provides a more effective method for the development of vibration isolation units with high attenuation rate.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：V414.33;TB535.1

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