Abstract

Guided wave based structural health monitoring (SHM) has been regarded as an effective tool in detecting early damages of structures thus avoid catastrophic failure. Unlike Lamb waves based SHM which had been well investigated, SH wave based SHM had been rarely reported due to the lacking of omni-directional SH wave piezoelectric transducer (OSH-PT). In this work, we firstly developed an OSH-PT based on thickness-poled, thickness shear (d15) PZT ring consisting of several elements. After size optimization, it is shown that even for the OSH-PT consisting of two half-rings, it can still generate and receive SH wave with good omni-directivity and the excited SH0-to-Lamb wave ratio is above 20dB in wideband. Then a sparse array system and a linear phased array system were developed using the half-ring based OSH-PTs, respectively. Results indicated that the proposed two systems can detect both surface defects and through-thickness defects at multi frequencies without baseline. The sparse array system has a good resolution in detecting a 4mm hole at 135kHz (0.17?) with the locating error of 12mm while the phased array system has a better resolution which can detect a 2mm hole with the locating error of only 6.2mm. Besides, both systems can detect multiple defects simultaneously. This work is expected to promote the applications of SH0 wave based SHM.

How to Cite:

Huan, Q. . & Li , F. ., (2019) “Struactural health monitoring based on SH wave sparse array and phased array system”, Review of Progress in Quantitative Nondestructive Evaluation .