Abstract:

In active Lamb wave structure health monitoring (SHM), the signal-to-noise (STN) of the damage scattering signal is the key factor in the accurate and stable monitoring. To solve the low STN problem in the real structure’s SHM, especially in composite SHM, an amplifying signal and imaging damage method based on the time reversal theory is purposed. By the character of Lamb wave propagation, the damage scattering signals are time reversed and remitted to the damage, and then they will arrive at the damage synchronously so that the damage scattering signal caught again will be amplified. Based on the focalization ability to the wave origin of time reversal theory, the wave propagation image is rebuilt to display the damage. Experiments on the carbon fiber reinforced composite board indicate that the sensing data energy can be amplified by this method, and the location and the range of the damage can be expressed well.

Key words: structure , health , monitoring , (SHM),  , Lamb , wave,  , time , reversal,  , adaptive , focalization,  , damage , detection