基于压电阻抗模型参数识别的结构健康监测研究

发布时间：2019-02-15 02:22

【摘要】：基于压电阻抗技术的结构健康监测具有对微小损伤检测灵敏度高、抗干扰能力强、信号采集方便快捷等优点,在金属材料、复合材料、混凝土结构的损伤监测中有广阔的应用前景。本文将压电阻抗技术用于压电元件的自损伤监测中,通过修改导纳模型,加入压电元件破坏与脱胶的损伤因子,利用遗传算法进行参数识别,拟合得到损伤导纳信号中的损伤因子值,并进行了相应的实验验证,结果表明,利用修改的导纳模型可以达到同时监测压电元件破坏与脱胶程度的目的。通过对导纳公式的数值模拟仿真发现压电阻抗对结构刚度变化检测灵敏度非常高,因此从结构尺寸和结构弹性模量两方面进行了相应的探索。厚钢板的槽损伤实验结果表明,结构厚度减小引起刚度降低,从而使压电导纳值减小。利用有限元方法对粘贴压电片的铝板进行分析,显示结构刚度与结构弹性模量成比例关系。在铝合金的疲劳损伤实验中,利用损伤识别指数对损伤导纳信号进行分析,并研究了导纳信号、弹性模量与疲劳加载次数之间的变化规律,通过导纳公式和测量信号拟合得到结构刚度随加载次数的变化。结果表明,基于压电阻抗技术可以有效地监测铝合金的疲劳损伤过程。最后,研究了压电阻抗信号与温度的关系,基于实验发现温度变化将引起阻抗信号幅值和谐振频率的移动,基于损伤识别指数研究了温度补偿算法,并进行了实验验证,结果表明,经过温度补偿的导纳曲线,可以利用相应的损伤识别参数进行结构健康监测。
[Abstract]:The structure health monitoring based on piezoelectric impedance technology has the advantages of high sensitivity to small damage detection, strong anti-interference ability, convenient and quick signal acquisition, etc., in metal materials, composite materials, etc. The damage monitoring of concrete structure has a broad application prospect. In this paper, piezoelectric impedance technique is applied to self-damage monitoring of piezoelectric elements. By modifying admittance model, adding damage factors of damage and degumming of piezoelectric elements, genetic algorithm is used to identify parameters. The results show that the modified admittance model can be used to monitor the degree of damage and degumming of piezoelectric elements simultaneously. Through the numerical simulation of admittance formula, it is found that piezoelectric impedance has a very high sensitivity to the structural stiffness change, so the corresponding exploration is made in terms of the structure size and the elastic modulus of the structure. The experimental results of slot damage of thick steel plate show that the decrease of structure thickness leads to the decrease of stiffness and the decrease of piezoelectric admittance. The finite element method is used to analyze the aluminum plate with piezoelectric plates. It is shown that the stiffness of the structure is proportional to the elastic modulus of the structure. In the fatigue damage test of aluminum alloy, the damage admittance signal is analyzed by damage identification index, and the variation law between admittance signal, elastic modulus and fatigue loading times is studied. Through admittance formula and measurement signal fitting, the change of structure stiffness with loading times is obtained. The results show that the piezoelectric impedance technique can effectively monitor the fatigue damage process of aluminum alloy. Finally, the relationship between the piezoelectric impedance signal and temperature is studied. Based on the experimental results, it is found that the amplitude and resonant frequency of the impedance signal will move. Based on the damage identification index, the temperature compensation algorithm is studied and verified by experiments. The results show that the corresponding damage identification parameters can be used to monitor the structure health through the admittance curve of temperature compensation.
【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】：TU317

【相似文献】