Structural health monitoring of plate structures using lamb wave methods

In this paper, waveform is used to excite Lamb waves in the test plates during experimental testing. The optimal excitation frequency will depend on the test configuration. In order to select an excitation frequency, dispersion curves are first created to show what frequency range is best suited for Lamb wave excitation. According to dispersion curves were created for the aluminum test plates and it was concluded that a frequency below 1 MHz will be used in order to only excite the fundamental S-0 and A(0) modes. Experiments are performed on the aluminum test plates described. Experimental testing is first performed on undamaged plates in order to determine the path-to-path and test-to-test variability in Lamb wave measurements in the absence of damage. The admittance data is analyzed in order to determine if any of the PZT transducers need to be replaced because of poor bonding or mechanical failure. The sensor diagnostic technique is applied to each plate and used to ensure proper consistency between PZT transducers