Acoustic event monitoring for triggering of health scan of a structure

• US 10,401,316 B2
• Filed: 05/23/2017
• Issued: 09/03/2019
• Est. Priority Date: 05/23/2017
• Status: Active Grant

• Current Assignee: Simmonds Precision Products, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Simmonds Precision Products, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Arsenault, Tyler, Carini, Peter J.
• Primary Examiner(s): Caputo, Lisa M
• Assistant Examiner(s): Cotey, Philip L
• Application Number:
  US15/603,156
• Publication Number:
  US 20180340898A1
• Time in Patent Office: 833 Days
• CPC Class Codes: B64F 5/60 Testing or inspecting aircraft components or systems
• CPC Class Codes: G01H 9/004 using fibre optic sensors light guides per se G02B6/00, acousto-optical devices specially adapted for gating or modulating in optical wave guides G02F1/125
• CPC Class Codes: G01M 11/085 the optical fiber being on or near the surface of the DUT
• CPC Class Codes: G01M 5/0016 of aircraft wings or blades
• CPC Class Codes: G01M 5/0066 by exciting or detecting vibration or acceleration vibration testing of structures G01M7/00
• CPC Class Codes: G01M 5/0091 by using electromagnetic excitation or detection
• CPC Class Codes: G01N 2291/2694 Wings or other aircraft parts
• CPC Class Codes: G01N 25/72 Investigating presence of flaws
• CPC Class Codes: G01N 29/2418 using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics photoacoustic cells G01N21/1702; measuring characteristics of vibrations by using radiation-sensitive means G01H9/00; acousto-optical conversion techniques for short-range imaging G01S15/8965; sound-producing devices using laser bundle G10K15/046

Abstract

Apparatus and associated methods relate to generating a trigger signal in response to detection of a triggering acoustic event sensed by one of a distributed network of optical acoustic sensors mechanically coupled to an aircraft structure. Each of the optical acoustic sensors is configured to generate an optical response signal indicative of an acoustic condition detected by the optical acoustic sensor. A controller receives the optical response signals and generates, if a triggering one of the optical response signals is indicative of a triggering acoustic event, a trigger signal. The controller also determines a location of the specific one of the distributed network of optical acoustic sensors that generated the triggering one of the optical response signals. In some embodiments, the trigger signal is sent to a Health & Usage Monitoring System configured to perform a health scan, in response to receiving the trigger signal, of the aircraft structure.

Claims

1. A system for monitoring an aircraft structure, the system comprising:

an optical fiber network extending along an aircraft structure;

an optical emitter optically coupled to the optical fiber network and configured to generate an optical signal and to transmit the generated optical signal to the optical fiber network;

a series of optical acoustic transducers optically coupled to the optical fiber network and mechanically coupled to the aircraft structure at a series of acoustic sensor locations, each of the series of optical acoustic transducers configured to receive the generated optical signal, to generate an optical response signal indicative of a detected passive acoustic condition at a respective acoustic sensor location, and to transmit the generated optical response signal to the optical fiber network;

an optical detector optically coupled to the optical fiber network and configured to receive the transmitted optical response signals generated by the series of optical acoustic transducers; and

a controller configured to generate a trigger signal configured to trigger an active health monitor scan, if a triggering one of the received optical response signals is indicative of a triggering acoustic event, the controller further configured to determine, based on a relative timing of the triggering one of the received optical response signals, a specific one of the acoustic sensor locations associated with a specific one of the series of optical acoustic transducers that generated the triggering one of the optical response signals associated with the generated trigger signal.

2. The system of claim 1, further comprising a Health &

Usage Monitoring System (HUMS) configured to receive the trigger signal and to perform, in response to receiving the trigger signal, a health scan of the aircraft structure at the specific one of the series of acoustic sensor locations.

3. The system of claim 2, wherein the HUMS comprises:

a mechanical diagnostics engine configured to actively monitor acoustic signals and to compare the monitored acoustic signals to a baseline acoustic signal.

4. The system of claim 3, wherein each of the series of optical acoustic transducers is a Fiber Bragg Grating (FBG) within the optical fiber network.

5. The system of claim 1, wherein the optical signal generated by the optical emitter has optical energy spanning a domain of wavelengths.

6. The system of claim 5, wherein each of the series of FBGs within the optical fiber has a different spatial frequency from others of the FBGs, so as to reflect a different subdomain of wavelengths of the domain of wavelengths spanned by the optical signal generated by the optical emitter.

7. The system of claim 1, wherein the optical fiber network comprises a series of optical fibers, and wherein each of the series of optical acoustic transducers is optically coupled to a corresponding one of the optical fiber.

8. The system of claim 1, wherein the aircraft structure is a wing.

9. The system of claim 1, further comprising a Structural Health Monitoring (SHM) system configured to receive the trigger signal and to perform, in response to receiving the trigger signal, a health scan of the aircraft structure at the specific one of the series of acoustic sensor locations.

10. The system of claim 9, wherein the SHM system is configured to actively generate acoustic signals, to detect acoustic responses to the actively generated acoustic signals, and to compare the detected acoustic responses with a baseline response.

11. The system of claim 1, further comprising an optical temperature transducer coupled to the aircraft structure at a temperature sensor location and configured to detect a temperature, to generate an optical signal indicative of the detected temperature, and to transmit the generated optical signal to the optical fiber network.

12. A method for monitoring health of an aircraft structure, the method comprising:

extending an optical fiber network along an aircraft structure;

generating, an optical signal;

transmitting the generated optical signal to the optical fiber network;

detecting, via a series of optical acoustic transducers mechanically coupled to the aircraft structure at a series of acoustic sensor locations along the optical fiber network, passive acoustic conditions at the series of acoustic sensor locations;

receiving, via the series of optical acoustic transducers, the transmitted optical signal;

generating, in response to receiving the transmitted optical signal via the series of optical acoustic transducers, optical response signals indicative of the detected passive acoustic conditions;

transmitting, via the series of optical acoustic transducers, the generated optical response signals to the optical fiber network;

receiving, via an optical detector, the transmitted optical signals;

generating, via a controller, a trigger signal configured to trigger an active health monitor scan, if a triggering one of the received optical response signals is indicative of a triggering acoustic event; and

determining, based on a relative timing of the triggering one of the received optical response signals via the controller, a specific one of the acoustic sensor locations associated with a specific one of the series of optical acoustic transducers that generated the triggering one of the optical response signals associated with the generated trigger signal.

13. The method of claim 12, further comprising:

receiving, via a Health &

Usage monitoring system (HUMS), the trigger signal; and

performing, by the HUMS in response to receiving the received trigger signal, a health scan of the aircraft structure at the specific one of the series of acoustic sensor locations.

14. The method of claim 12, further comprising:

actively generating, via a Structural Health Monitoring (SHM) system, acoustic signals;

sensing, via the SHM system, acoustic responses to the actively generated acoustic signals; and

comparing, via the SHM system, the sensed acoustic responses to a baseline response.

15. The method of claim 12, wherein the generated optical signal has optical energy spanning a domain of wavelengths.

16. The method of claim 15, wherein generating optical response signals indicative of the detected acoustic conditions comprises:

reflecting, via a series of Fiber Bragg Gratings (FBGs), portions of the transmitted optical signal from within the optical fiber network.

17. The method of claim 16, wherein each of the FBGs has a different spatial frequency from the others, so as to reflect a different subdomain of wavelengths of the domain of wavelengths spanned by the optical signal generated by the optical emitter.

18. The method of claim 12, wherein the aircraft structure is a wing.

19. The method of claim 12, wherein the aircraft structure is an engine nacelle.

20. The method of claim 12, further comprising:

detecting, via an optical temperature transducer coupled to the aircraft structure at a temperature sensor location, a temperature;

receiving, via the optical temperature transducers, the transmitted optical signal;

generating, in response to receiving the transmitted optical signal via the optical temperature transducer, an optical response signal indicative of the detected temperature; and

transmitting the generated optical response signal to the optical fiber network.