Distributed Fiber Optic Acoustic Emission Sensor for Crack Growth Monitoring in Advanced Aircraft Structures

Physical Optics Corporation, a leader in the development of distributed fiber optic sensors for nondestructive inspection and evaluation, proposes to develop a multipoint, continuously operating distributed fiber optic acoustic emission sensor (FOAES) system for the detection and monitoring of cracks in aging aircraft structures and in next-generation fighters. Based on a distributed array of in-line fiber Bragg gratings that are sensitive to acoustic-emission waves, the proposed FOAES system can either be embedded or surface-mounted in a wide variety of aircraft materials and structures. The goals of the proposed Phase I effort are: (1) to demonstrate quantitative acoustic emission detection in aircraft materials with multiplexed fiber gratings; (2) to design an automated optoelectronic sensor readout system; (3) to integrate the fiber grating system and a bench top optoelectronic sensor readout and demonstrate its performance as a distributed acoustic emission sensor system; and (4) to test the FOAES instrument for the quantitative structural analysis of aircraft structural materials (i.e., aluminum and stainless steel) in the laboratory; and (5) to demonstrate the commercial potential of the FOAES technology.