A Lamb Waves Based Ultrasonic System for the Simultaneous Data Communication, Defect Inspection, and Power Transmission.

Lamb-wave-based structural health monitoring (SHM) has attracted extensive attention in recent years. This article aims to realize the functions of data communication, defect detection, and energy transmission through piezoelectric transducers. In this work, the S mode at 500 kHz and the A mode at 150 kHz are selected as the carrier waves and the optimized excitation frequencies are determined through analytical investigation and frequency sweeping experiments. The S mode is used for data communication and defect inspection due to the high excitation frequency and low dispersion properties. A single piezoelectric sensing element acts as the transmitter and a nine-element piezoelectric transducer array (PTA) is the receiver. Their roles exchange in terms of energy transmission based on the A mode. Simultaneous data communication and energy transmission are achieved based on the frequency division multiplexing (FDM) strategy. After performing a matched filter on the received signals, the digital data information can be recovered under the interference of the energy transmission signal. The synthetic aperture imaging technology (SAFT) is adopted for accurately locating defects on aluminum plates. In terms of energy transmission, a constructive interference performance is achieved by the transducer array with a transmitted power of 3.81 mW. This system has great potential for health monitoring of the enclosed structure by eliminating the cumbersome wires for powering and communication.