基于压电传感器的导波信号频散特性测量

PZT Sensor Based Dispersion of Guided Wave Measurement

基于压电传感器的导波结构损伤监测与检测是近年来发展起来的前沿无损检测和结构健康监测技术之一。本文针对不同监测对象和条件下,基于压电传感器的结构导波信号激发和传播频散特性复杂问题,采用等脉宽窄带信号分时激励,并对结构响应信号进行归一化合成,进而通过时频分析方法,获取压电传感器激励和传感下的结构导波信号频散特性分布。实验验证结果表明,上述方法可较为简便地获取基于压电传感器的待测结构导波信号频散特性,从而可选择合适的激励信号频率与脉宽,实现单一模式的导波监测信号,简化信号复杂度。

PZT sensor and guided wave based damage monitoring and testing is one of the front technologies in nondestructive testing and structural health monitoring recently. The actuation and propagation of guided wave in structure under the excitation of PZT sensor should be complicated for the different objects and conditions. The time-sharing excitations of equal width narrowband pulses were adopted. The normalized structural responses captured by PZT sensor were superimposed and analyzed by using time-frequency processing. The dispersion of the structural response under the excitation and sensing of PZT sensor were obtained. The experimental verification and results shown that the method mentioned above can acquire the dispersion characteristics of guided wave which is measured by PZT sensors, so that the appropriate central frequency and pulse width of the excitation can be selected to realize single mode dominant guided wave and simplify the signal complexity.