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Development of Wireless Ultrasonic Propagation Imaging System

M.M. SHRESTHA, S.Y. CHONG, J.-R. LEE

Abstract


Ultrasonic propagation imaging (UPI) systems connected with PZT, fiber Bragg grating, air-coupled transducers, laser Doppler vibrometers have been developed by our research team and widely used in in-service structural inspection and part manufacturing quality control. In this paper, we introduced an UPI system coupled with wireless ultrasonic sensing to realize a wireless UPI system. The system consists of a high-speed laser ultrasonic scanning system, a preamplifier-integrated piezoelectric (PZT) sensor network, an embedded wireless ultrasonic device (WUD), and a computer. The laser ultrasonic scanning system has various scanning rate from 100 Hz to 20 kHz. Then, the WUD has an integrated two-channel 12-bit analog-todigital converter (ADC) with the maximum sampling rate of 20 MHz. Figure 1 shows that an experimental setup was configured to perform the feasibility test on the proposed wireless UPI system. An integrated-amplifier PZT sensor installed on a CFRP wing plate was connected to the WUD. The ADC sampling rate of 2 MHz was set in the WUD. Since the WUD was built with a WiFi modem, all the operation can be remotely controlled by a computer through a wireless network. In this work, a horizontal scan line (40 mm) with the scanning interval of 1 mm was performed by the wireless UPI system at the scanning rate of 10 kHz. In each laser impinging point, the corresponding generated ultrasound was acquired accordingly to the scanning rate of 10 kHz in the WUD. As shown in Fig. 1, the signal was successfully reconstructed back in the computer. This has shown that the wireless UPI system was capable to acquire the ultrasound continuously when the laser started to scan in a horizontal line. Finally, the wireless UPI system performed the two-dimensional ultrasound acquisition on a desired inspection area of an aircraft structure. Then, the acquired ultrasounds were processed for damage detection and evaluation.

doi: 10.12783/SHM2015/317


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