21-000001440: Smart Ultrasonic Node for Structural health Monitoring (SUN-SHM)

The main objective of the proposed three-year research program is to design, develop, and validate a miniaturized Smart Ultrasonic N,ode (SUN) for structural health monitoring (SHM). The condition-based maintenance through on-demand diagnosis of structural health i,s attractive and provides uninterrupted operation of critical structures. The diagnostics involves real-time fault monitoring and di,agnosis, background studies, and fault analysis. This program will address the challenges with the pre-stage of diagnostics that inv,olves sensors for detection of defects and faults in structures using ultrasonic waves. Conventional SHM systems utilize piezoelectr,ic transducers, attached to long wires, for generating and/or detecting ultrasonic waves. However, this approach suffers from multip,le drawbacks including poor survivability in harsh environment, bulky size, complexity in distributed monitoring, high cost, and sus,ceptibility to electromagnetic interference. Under-the-paint SHM technologies are compact and modular, rendering them suitable for m,onitoring large and complex structures such as naval ship surfaces. In the proposed SUN-SHM system, fibers with integrated acoustic,sources transmit ultrasonic waves right at desired distant locations over a large structure.The proposed SUN in this program efficie,ntly generates ultrasonic waves in different locations of a structure by driving an array of piezoelectric transducers coupled to fi,bers (as waveguides). This program will use a single optical fiber for reliable and multiplexable power and data transfer to individ,ual SUNs from a control hub. Our research will lead to the development of an application-specific integrated circuit (ASIC) in a hig,h-voltage complementary metal-oxide semiconductor (CMOS) process with 1) multiple channels of high-voltage drivers for driving an ar,ray of piezoelectric transducers (8 transducers in this program as a proof of concept), 2) efficient power management circuitry for,receiving power andgenerating different power supplies regardless of the input voltage/power variations, and 3) data recovery and co,ntrollable signal generation circuitry to receive commands from the control hub (in the form of modulated light intensity) and gener,ate driving signals with desired waveforms across each piezoelectric transducer. This research will also lead to an optical system f,or power and data transfer with multiplexing capability. Fundamental advancements provided by this program will enable the developme,@##@0002,nt of advanced multiplexable SUNs, significantly benefiting the DoDs ability to detect defects and faults in structures such as shi,ps, aircraft, and vehicles.The goal of this program will be accomplished by achieving three major milestones through executing four,) components to drive one piezoelectric transducer with optimal waveform; Milestone-2 (Year 2): Develop and demonstrate an optical s,ystem with multiplexing capability using a single fiber for power and data delivery to multiple SUNs; Milestone-3 (Year 3): Develop,and demonstrate an 8-channel CMOS ASIC to drive 8 piezoelectric transducers in a 20200.3 mm3 SUN with multiplexing capability. Upo,n the successful completion of this program, a 20200.3 mm3 SUN prototype with the unique capabilities of driving 8 piezoelectric t,ransducers (which can further be scaled up in future) and optical multiplexing (for addressing individual SUNs) will be developed an,d demonstrated. We will also deliver ONR reports, technical review presentation, and conference and journal publications in each yea,r of this program.Approved for Public Release