基于应变模态的压电智能层合板结构损伤识别方法研究

发布时间：2018-01-14 09:25

本文关键词：基于应变模态的压电智能层合板结构损伤识别方法研究　出处：《南京航空航天大学》2015年硕士论文　论文类型：学位论文

【摘要】：由于复合材料层合板在使用过程中容易出现损伤,这会导致其材料的综合性能下降,有时会使结构部件突然断裂,本文针对此问题从航空航天工程应用背景出发,利用压电智能系统对复合材料层合结构进行损伤识别分析。主要研究内容如下:(1)从理论上对比分析了基于结构固有频率和应变模态的损伤识别方法的优缺点,发现基于固有频率的方法虽然可以检测损伤,但是不能确定损伤的位置,而基于应变模态的方法可以很好的对损伤进行定位和定量分析。并用该理论为后面的模拟和试验分析提供技术支持。(2)模拟分析复合材料层合板损伤识别。复合材料损伤识别主要包括:损伤存在识别、损伤定位、损伤定量这三步,本文首先基于固有频率,位移模态和应变模态这三种方法对复合材料层合板进行损伤分析,发现应变模态对损伤识别效果最敏感,然后在基于应变模态变化率、应变模态变化差和应变模态差分这三种方法对复合材料层合板进行损伤识别分析,发现这三种方法对单点损伤识别效果都很好,但是只有应变模态变化率能很好的对多点损伤进行定位和定量分析。(3)通过试验来对复合材料层合板单点损伤识别。首先根据理论分析搭建试验平台;然后通过压电应变片采集压电信号并通过滤波降噪及小波变换对信号进行处理,得到幅频信号并找出复合材料层合板的各阶固有频率及其对应的幅值;然后根据得到的数据进行三次样条插值从而得到复合材料层合板各阶固有频率下对应的应变模态振型图,再通过对比有损和完好层合板的应变模态振型图可以找到损伤出现的大概位置;最后通过在损伤位置附件增加压电应变片的数量,达到对损伤进行精确定位的目的。在对损伤进行定位的基础上,再用同样的方法对损伤进行定量分析。
[Abstract]:The composite laminates are prone to damage in the process of use, which will lead to the deterioration of the comprehensive properties of the materials, and sometimes make the structural parts suddenly break. This paper aims at this problem from the aerospace engineering application background. Damage identification and analysis of composite laminated structures using piezoelectric intelligent system. The main research contents are as follows: 1). The advantages and disadvantages of damage identification methods based on natural frequencies and strain modes of structures are compared and analyzed theoretically. It is found that the method based on natural frequency can detect the damage, but it can not determine the location of the damage. The method based on strain mode can be used to locate and quantitatively analyze the damage and provide technical support for the simulation and experimental analysis. The damage identification of composite laminates mainly includes: damage identification. Damage location and damage quantification are three steps. Firstly, based on the three methods of natural frequency, displacement mode and strain mode, the damage analysis of composite laminates is carried out, and it is found that the strain mode is the most sensitive to damage identification. Then based on strain mode change rate, strain mode variation difference and strain mode difference, the damage identification of composite laminated plate is carried out. It is found that these three methods are very effective for single point damage identification. But only the strain mode change rate can locate and quantitatively analyze the damage of multiple points. (3) the single point damage of composite laminates can be identified by experiments. Firstly, the test platform is built according to the theoretical analysis. Then the piezoelectric strain gauge is used to collect the voltage signal and the signal is processed by filtering and denoising and wavelet transform. The amplitude-frequency signal is obtained and the natural frequencies of the composite laminates and their corresponding amplitudes are found out. Then the cubic spline interpolation is carried out according to the obtained data to obtain the corresponding strain mode vibration pattern of composite laminated plates at different natural frequencies. Then, by comparing the modal pattern of the damaged and intact laminated plates, the location of the damage can be found. Finally, by increasing the number of piezoelectric strain gauges in the attachment of the damage position, the aim of accurate location of the damage is achieved. On the basis of the location of the damage, the same method is used to quantitatively analyze the damage.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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