微悬臂梁的激励与动态特性研究

发布时间：2018-06-07 10:53

本文选题：模态分析 + 动态特性测试　；参考：《华中科技大学》2015年硕士论文

【摘要】：微米尺寸结构应用广泛,非常规的使用环境对其动态特性要求比宏观结构高,依然采用宏观结构测振系统无法满足对微小结构的有效激励与测振。针对实际测试需求,本文搭建了以压电底座激励和多普勒激光技术相结合的微结构测试系统,实现微悬臂梁前七阶固有振动的有效激励和模态参数的提取,探究微悬臂梁不同区段厚度变化对动态特性的影响。论文工作如下:(1)对微结构激励方法、振动检测技术及试验模态估计方法进行了综述,对基于压电陶瓷的激励方式与多普勒测振原理进行了详细介绍,并完成了测振系统中的各部分选型和整体搭建。设计了微悬臂梁对比实验并选择可行的尺寸控制方法,有限元方法计算出固有频率受厚度尺寸的影响,仿真证明了宽度方向的尺寸微小变化对测试结果的影响可以忽略。(2)建立了微悬臂梁频响函数测试误差模型,选择了合理频响估计。采用快速正弦扫描激励,完成了微悬臂梁振动测试,由频响函数计算出脉冲响应,引入最小二乘复指数法进行模态分析,建立了极点稳态图,并依据模态判断准则合理挑选出极点,实现了模态参数计算。完成对照实验中不同厚度微悬臂梁的模态参数提取,并详细分析了不同区段厚度变化对各阶固有频率的影响规律。本文研究工作完善了微尺寸结构的实验模态分析方法,对推动动态特性测试技术的发展具有一定意义。
[Abstract]:The micrometer structure is widely used, and its dynamic characteristics are required higher in the unconventional environment than in the macro structure. The vibration measurement system still can not satisfy the effective excitation and vibration measurement of the micro structure. According to the actual test demand, a micro-structure testing system based on piezoelectric pedestal excitation and Doppler laser technology is built to realize the effective excitation and modal parameter extraction of the first seven natural vibration of the micro-cantilever beam. The effect of thickness variation of different sections on dynamic characteristics of micro cantilever beam was investigated. The main work of this paper is as follows: (1) the excitation methods, vibration detection techniques and experimental modal estimation methods of microstructures are summarized, and the excitation mode based on piezoelectric ceramics and the principle of Doppler vibration measurement are introduced in detail. And completed the vibration measurement system in each part of the selection and the overall construction. The contrast experiment of micro-cantilever beam is designed and the feasible dimension control method is selected. The finite element method calculates that the natural frequency is affected by the thickness dimension. The simulation results show that the influence of the small change of the width direction on the test results can be neglected. (2) the error model of the frequency response function of the micro cantilever beam is established, and the reasonable frequency response estimation is selected. The vibration test of micro-cantilever beam was completed by using fast sine scanning excitation. The pulse response was calculated by frequency response function, and the modal analysis was carried out by introducing the least square complex exponent method, and the pole steady-state diagram was established. According to the modal judgment criterion, the poles are reasonably selected, and the modal parameter calculation is realized. The modal parameters of micro-cantilever beams with different thickness were extracted and the influence of thickness of different sections on the natural frequencies was analyzed in detail. In this paper, the experimental modal analysis method of micro-size structures is improved, which is of great significance to the development of dynamic characteristic testing technology.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH825

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