Fiber-Optic Ultrasonic Generation and Sensing
Abstract
The goal of this project is to investigate novel fiber-optic powered ultrasonic generation, durable fiber Bragg grating (FBG) sensors, and low-noise diode lasers that can significantly enhance the capability and functionality of future fiber-optic ultrasonic test systems and acoustic emission systems for structural health monitoring (SHM). Specific research objectives include: (1) study the use of light to power many piezoelectric transducers along an optical fiber; (2) develop fabrication methods based on fs-lasers for various types of FBGs that can retain >90% of the mechanical strength of pristine fibers; and (3) model, develop, and characterize diode lasers that are self-injection locked to high-finesse Fabry-Perot interferometers for highly-sensitive acoustic emission (AE) detection.Advanced structural health monitoring technologies are a key enabler to shift the maintenance paradigm from the current ~time based~, where maintenance is performed at prescheduled times. to ~condition based~, where sensor systems are installed on the structure to provide the condition of structural health and maintenance is only performed when it is deemed necessary based on the actual health condition. Ultrasonic testing and AE are among the most powerful tools in SHM and expected to play an important role in ~condition-based~ maintenance paradigm. If successful, the research will provide solutions to several key technical challenges toward the development of practical fiber-optic ultrasonic testing systems and AE sensor systems. Specifically, the implementation of the proposed distributed fiber-optic power conversion and ultrasonic generation system, together with the distributed fiber-optic ultrasonic sensors that are being developed in other projects at the PI~s group and elsewhere, will lay a solid foundation to realize the vision of a fiber-optic/piezoelectric hybrid ultrasonic testing system. The investigation on the fabrication of mechanically strong and thermally stable gratings with complex grating structures using ultrafast lasers will accelerate the transition of grating sensor technology from lab to practical applications and lead to grating sensors that can be permanently installed on Naval platforms and perform structural health monitoring over the lifetime of the platform. The diode lasers developed from this research will significantly improve the performance of fiber-optic AE sensor systems in terms of sensitivity, cost, weight, and size.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 10, 2018
- Source ID
- N000141812273
Entities
People
- Ming Han
Organizations
- Michigan State University
- Office of Naval Research
- United States Navy