Sensors and systems for structural health monitoring

• US 20050061076A1
• Filed: 09/16/2004
• Published: 03/24/2005
• Est. Priority Date: 09/22/2003
• Status: Active Grant

• Current Assignee: Advanced Structure Monitoring, Inc.
• Original Assignee: Advanced Structure Monitoring, Inc.
• Inventors: Kim, Hyeung-Yun
• Granted Patent: US 7,117,742 B2
• Time in Patent Office: Days
• US Class Current: 73/587
• CPC Class Codes: G01H 11/00 Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by detecting changes in electric or magnetic properties
• CPC Class Codes: G01H 11/08 using piezoelectric devices
• 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 11/086 Details about the embedment of the optical fiber within the DUT
• CPC Class Codes: G01M 5/0033 by determining damage, crack or wear
• 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 2291/011 Velocity or travel time
• CPC Class Codes: G01N 2291/015 Attenuation, scattering
• CPC Class Codes: G01N 2291/02491 Materials with nonlinear acoustic properties
• CPC Class Codes: G01N 2291/0258 Structural degradation, e.g. fatigue of composites, ageing of oils
• CPC Class Codes: G01N 2291/0422 Shear waves, transverse waves, horizontally polarised waves
• CPC Class Codes: G01N 2291/0423 Surface waves, e.g. Rayleigh waves, Love waves
• CPC Class Codes: G01N 2291/0427 Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever
• CPC Class Codes: G01N 2291/106 one or more transducer arrays
• CPC Class Codes: G01N 29/043 in the interior, e.g. by shear waves
• CPC Class Codes: G01N 29/0609 Display arrangements, e.g. colour displays indicating or recording in connection with measuring in general G01D
• CPC Class Codes: G01N 29/0672 by acoustic tomography medical tomography A61B8/13
• CPC Class Codes: G01N 29/07 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 29/223 Supports, positioning or alignment in fixed situation mounting transducers per se G10K11/004
• CPC Class Codes: G01N 29/245 : Ceramic probes, e.g. lead zirconate titanate [PZT] probes
• CPC Class Codes: G01N 29/2475 : Embedded probes, i.e. probes incorporated in objects to be inspected
• CPC Class Codes: G01N 29/2493 : Wheel shaped probes
• CPC Class Codes: G01N 29/28 : providing acoustic coupling , e.g. water impedance matching G10K11/02
• CPC Class Codes: G01N 29/4418 : with a model, e.g. best-fit, regression analysis
• CPC Class Codes: G01N 29/4463 : Signal correction, e.g. distance amplitude correction [DAC], distance gain size [DGS], noise filtering

Abstract

Sensors and systems for monitoring structural health conditions. The present invention provides a device for monitoring structural health conditions including a dielectric substrate, a piezoelectric device for actuating and/or sensing Lamb waves, a molding layer deposited over the piezoelectric device, a cover layer deposited over the molding layer and a hoop layer surrounding the piezoelectric device and being attached to the substrate. The device further includes an optical fiber coil sensor attached to the dielectric substrate, where the coil sensor has a rolled optical fiber cable and a coating layer applied to the rolled optical fiber cable. The present invention also provides a diagnostic patch network that includes a plurality of patch sensors attached to a host structure and a bridge box connected to the patch sensors. The bridge box sends information of structural health conditions to and receive power from a ground control system using a wireless communication technique.

Claims

1. A device for monitoring structural health conditions, comprising:

a dielectric substrate;

at least one buffer layer attached to the substrate;

a piezoelectric device attached to the at least one buffer layer, said piezoelectric device configured to generate and receive signals;

a molding layer deposited over said piezoelectric device;

a cover layer deposited over said molding layer; and

a pair of electrical wires coupled to the piezoelectric device.

2. The device of claim 1, wherein said at least one buffer layer is comprised of polymer or metal.

3. The device of claim 1, wherein said molding layer is comprised of epoxy, polyimide or silicon-polyimide, and wherein said cover layer is comprised of metal.

4. The device of claim 1, further comprising a protective layer deposited over the cover layer, said protective layer being comprised of epoxy or polyimide.

5. The device of claim 1, further comprising:

a hoop layer attached to the substrate and comprised of a dielectric insulating material, said hoop layer surrounding said at least one buffer layer.

6. The device of claim 1, further comprising:

an optical fiber coil attached to said substrate, said optical fiber coil comprising;

a rolled optical fiber cable; and

a coating layer applied to the rolled optical fiber cable,

wherein a preset tensional force is applied during a rolling process of said optical fiber cable and the coating layer sustains tensional stress of the rolled optical fiber cable.

7. The device of claim 6, wherein said coating layer is comprised of metal or polymer.

8. The device of claim 6, wherein said coating layer is comprised of zinc oxide, silicon oxide or tantalum oxide.

9. The device of claim 1, wherein said signals are Lamb waves.

10. An optical fiber coil sensor for monitoring structural health conditions, comprising:

a rolled optical fiber cable; and

a coating layer applied to the rolled optical fiber cable,

wherein a preset tensional force is applied during a rolling process of said optical fiber cable and the coating layer sustains tensional stress of the rolled optical fiber cable.

11. The sensor of claim 10, wherein said coating layer is comprised of metal or polymer.

12. The sensor of claim 10, wherein said coating layer is comprised of zinc oxide, silicon oxide or tantalum oxide.

13. The sensor of claim 10, further comprising a through hole along a direction normal to a plane defined by the rolled optical fiber cable.

33. The system of claim 32, wherein the two sensors and the actuator/sensor have optical fiber coil sensors as defined in claim 10, each of said optical fiber coil sensors having a serial or a parallel connection to other optical fiber coil sensor.

14. A device for monitoring structural health conditions, comprising:

a dielectric substrate;

at least one sensor attached to said substrate;

a hoop layer surrounding said at least one sensor and being attached to said substrate;

a molding layer deposited over'"'"'said at least one sensor; and

a cover layer deposited over said molding layer.

15. The device of claim 14, wherein said at least one sensor comprises:

at least one buffer layer attached to the substrate;

a piezoelectric device attached to the at least one buffer layer, said piezoelectric device configured to generate and receive signals; and

a pair of electrical wires coupled to said piezoelectric device

16. The device of claim 14, wherein said at least one sensor comprises:

an optical fiber coil sensor attached to the substrate, said optical fiber coil sensor comprising;

a rolled optical fiber cable; and

a coating layer applied to the rolled optical fiber cable,

wherein a preset tensional force is applied during a rolling process of said optical fiber cable and the coating layer sustains tensional stress of the rolled optical fiber cable.

17. The device of claim 14, wherein said at least one sensor comprises:

at least one buffer layer attached to the substrate;

a piezoelectric device attached to the at least one buffer layer, said piezoelectric device configured to generate and receive signals;

a pair of electrical wires coupled to said piezoelectric device;

an optical fiber coil sensor attached to the substrate, said optical fiber coil sensor comprising;

a rolled optical fiber cable; and

a coating layer applied to the rolled optical fiber cable,

wherein a preset tensional force is applied during a rolling process of said optical fiber cable and the coating layer sustains tensional stress of the rolled optical fiber cable.

18. A device for monitoring structural health conditions, comprising:

a bottom substrate;

a top substrate;

at least one sensor sandwiched between the top and bottom substrates; and

a hoop layer surrounding said at least one sensor and being attached to said top substrate and bottom substrate.

19. The device of claim 18, wherein said at least one sensor comprises:

a bottom buffer layer attached to the substrate, said bottom buffer layer comprising at least one sublayer;

a piezoelectric device attached to the bottom buffer layer, said piezoelectric device configured to generate and receive signals;

a top buffer layer attached to the piezoelectric device, said top buffer layer comprising at least one sublayer; and

a pair of electrical wires coupled to said piezoelectric device

20. The device of claim 18, wherein said at least one sensor comprises:

an optical fiber coil sensor attached to the bottom and top substrates, said optical fiber coil sensor comprising;

a rolled optical fiber cable; and

a coating layer applied to the rolled optical fiber cable,

wherein a preset tensional force is applied during a rolling process of said optical fiber cable and the coating layer sustains tensional stress of the rolled optical fiber cable.

21. The device of claim 18, wherein said at least one sensor comprises:

a bottom buffer layer attached to the substrate, said bottom buffer layer comprising at least one sublayer;

a piezoelectric device attached to the bottom buffer layer, said piezoelectric device configured to generate and receive signals;

a top buffer layer attached to the piezoelectric device, said top buffer layer comprising at least one sublayer;

a pair of electrical wires coupled to said piezoelectric device

an optical fiber coil sensor attached to the bottom and top substrates, said optical fiber coil sensor comprising;

a rolled optical fiber cable; and

a coating layer applied to the rolled optical fiber cable,

wherein a preset tensional force is applied during a rolling process of said optical fiber cable and the coating layer sustains tensional stress of the rolled optical fiber cable.

22. A diagnostic patch washer, comprising:

a ring-shaped support element having a groove along a circumferential direction and a notch along a radial direction;

at least one sensor contained within the groove; and

a ring-shaped lid for covering said groove.

23. The diagnostic patch washer of claim 22, wherein the at least one sensor comprises:

a piezoelectric device attached to the support element; and

a pair of electrical wires coupled to said piezoelectric device,

wherein the pair of electrical wires pass through the notch.

24. The diagnostic patch washer of claim 22, wherein the at least one sensor comprises:

an optical fiber coil sensor attached to the support element, said optical fiber coil sensor comprising;

a rolled optical fiber cable; and

a coating layer applied to the rolled optical fiber cable,

wherein a preset tensional force is applied during a rolling process of said optical fiber cable and the coating layer sustains tensional stress of the rolled optical fiber cable, and wherein two ends of the optical fiber cable pass through the notch.

25. The diagnostic patch washer of claim 22, wherein the at least one sensor comprises:

a piezoelectric device attached to the support element;

a pair of electrical wires coupled to said piezoelectric device;

an optical fiber coil sensor attached to-the support element, said optical fiber coil sensor comprising;

a rolled optical fiber cable; and

a coating layer applied to the rolled optical fiber cable,

wherein a preset tensional force is applied during a rolling process of said optical fiber cable and the coating layer sustains tensional stress of the rolled optical fiber cable and wherein the pair of electrical wires and two ends of the optical fiber cable pass through the notch.

26. A diagnostic network patch system for monitoring health conditions of a host structure, comprising:

a plurality of patches attached to the host structure in a predetermined pattern, at least one of said plurality of patches capable of receiving vibrational waves generated by at least one other of said plurality of patches; and

a bridge box coupled to said plurality of patches, said bridge box comprising a RF telemetry system for sending signals received from said plurality of patches to a ground control system via wireless means.

27. The system of claim 26, wherein the predetermined pattern has a pentagonal configuration.

28. The system of claim 26, wherein the predetermined pattern has a plurality of strip configurations.

29. The system of claim 26, further including:

a computer connected to said bridge box and configured to coordinate operation of said plurality of patches.

30. The system of claim 26, wherein said bridge box comprises a plurality of micro strip antennas for receiving power from a ground control system via wireless means.

31. The system of claim 30, wherein said bridge box has a honeycomb structure comprising:

a honeycomb core; and

multilayer dielectric laminate having an outer faceplate that contains said micro strip antennas.

32. The system of claim 26, wherein each of said plurality of patches comprises:

two sensors for receiving vibrational waves; and

an actuator/sensor interposed between said two sensors and configured to generate or receive vibrational waves.