Development of Wireless Ultrasonic Propagation Imaging System for In-Situ Aircraft Inspection

Recently, laser ultrasonic propagation imaging (UPI) system has been greatly increased the attention of researchers for structural health management (SHM) application. The system has shown the promising results in the damage diagnosis of aircraft structures. However, the inspection was conducted in the experimental laboratory on a structure, which has been dissembled from an aircraft, which is not practical for the in-situ and large-scale aircraft structure inspection. This paper presents a wireless UPI system to realize the in-situ aircraft structure inspection. 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 ground SHM system. In this work, four 8-channel analog multiplexers were used to connect the sensor nodes, which were installed along the webs of an aircraft, to the WUD with an integrated four-channel 12-bit analog-to-digital converter (ADC). The maximum sampling frequency of the ADC is 80 MHz. The WUD has an integrated Wi-Fi modem (802.11b/g/n). As further work, the UPI system will perform the inspection on a desired area with a selected local sensor node. Then, the acquired ultrasound will send to the ground SHM system to process for damage evaluation.