Capacitive sensor array for structure damage detection or health assessment

Patent metadata

Field	Value
Publication number	US-10436734-B2
Application number	US-201715624867-A
Country	US
Kind code	B2
Filing date	Jun 16, 2017
Priority date	Jun 16, 2017
Publication date	Oct 8, 2019
Grant date	Oct 8, 2019

Abstract

An example system includes an array of capacitive elements, a measurement lead, and a ground plane lead. One or more respective capacitive elements of the array of capacitive elements include a dielectric substrate and a corresponding top conductive layer, with each dielectric substrate configured to be positioned between the top conductive layer and a common ground plane. The measurement lead is coupled to the top conductive layer of each of the one or more respective capacitive elements. The ground plane lead is configured to be coupled to the common ground plane. The capacitive elements are structured such that the capacitive elements have varying respective capacitances, and the capacitive elements are arranged positionally within the array of capacitive elements such that a change in total capacitance is indicative of damage to a particular capacitive element at a particular position within the array of capacitive elements.

First claim

What is claimed is:

1. A system configured to detect in-situ structural damage, the system comprising:
an array of capacitive elements, wherein one or more respective capacitive elements of the array of capacitive elements comprise a dielectric substrate and a corresponding top conductive layer, wherein each dielectric substrate is configured to be positioned between the top conductive layer and a common ground plane;
a measurement lead coupled to the top conductive layer of each of the one or more respective capacitive elements; and
a ground plane lead configured to be coupled to the common ground plane,
wherein the capacitive elements of the array of capacitive elements are structured such that the capacitive elements have varying respective capacitances, and
wherein the capacitive elements of the array of capacitive elements are arranged positionally within the array of capacitive elements such that a change in total capacitance between the measurement lead and the ground plane lead is indicative of damage to a particular capacitive element at a particular position within the array of capacitive elements.

2. The system of claim 1 , wherein the system is configured as a flexible sensor.

3. The system of claim 1 , further comprising a bottom conductive layer functioning as the common ground plane for the system, wherein each dielectric substrate is positioned between the bottom conductive layer and the top conductive layer corresponding to the dielectric substrate.

4. The system of claim 3 , wherein the system is configured as a flexible sensor.

5. The system of claim 1 :
wherein the system is configured to be applied on a surface of a structure with the array of capacitive elements spread out over the surface of the structure such that the change in total capacitance is indicative of damage to a particular position of the surface of the structure, and
wherein the common ground plane comprises a metallic surface of the structure.

6. The system of claim 5 , wherein the metallic surface comprises an inner layer of the structure that is beneath an outer layer of the structure.

7. The system of claim 1 , wherein the capacitive elements of the array of capacitive elements have varying geometric areas such that the capacitive elements have varying respective capacitances.

8. The system of claim 1 , wherein the capacitive elements of the array of capacitive elements are connected as at least two rows of capacitive elements.

9. The system of claim 1 , further comprising a measurement device to which the measurement lead and the ground plane lead are coupled, wherein the measurement device is configured to measure the change in total capacitance of the array of capacitive elements.

10. The system of claim 9 , further comprising a wireless communication node coupled to the measurement device, the wireless communication node configured to communicate an indication of the total capacitance of the array of capacitive elements to another device.

11. The system of claim 9 , further comprising a wireless communication tag coupled to the measurement device, the wireless communication tag configured to store an indication of the total capacitance of the array of capacitive elements.

12. A system configured to detect in-situ structural damage, the system comprising:
an array of capacitive elements;
a measurement lead coupled to each of the capacitive elements of the array of capacitive elements; and
a ground plane lead coupled to each of the capacitive elements of the array of capacitive elements,
wherein the capacitive elements of the array of capacitive elements are structured such that the capacitive elements have varying respective capacitances, and
wherein the capacitive elements of the array of capacitive elements are arranged positionally within the array of capacitive elements such that a change in total capacitance between the measurement lead and the ground plane lead is indicative of damage to a particular capacitive element at a particular position within the array of capacitive elements.

13. The system of claim 12 , wherein one or more respective capacitive elements of the array of capacitive elements comprise a dielectric substrate positioned between a corresponding top conductive layer and a corresponding bottom conductive layer, wherein the measurement lead is coupled to the top conductive layers of each of the one or more respective capacitive elements, and wherein the ground plane lead is coupled to the bottom conductive layer of each of the one or more respective capacitive elements.

14. The system of claim 12 , wherein each of one or more respective capacitive elements of the array of capacitive elements comprises a first electrode that is interdigitated with a second electrode, wherein the measurement lead is coupled to the first electrode of each of the one or more respective capacitive elements, and wherein the ground plane lead is coupled to the second electrode of each of the one or more respective capacitive elements.

15. The system of claim 12 , wherein the system is configured to be applied on a surface of a structure with the array of capacitive elements spread out over the surface of the structure such that the change in total capacitance is indicative of damage to a particular position of the surface of the structure.

16. The system of claim 12 , wherein the capacitive elements of the array of capacitive elements have varying geometric areas such that the capacitive elements have varying respective capacitances.

17. A method for detecting in-situ structural damage, the method comprising:
applying a flexible sensor to a surface of a structure, wherein the flexible sensor comprises an array of capacitive elements having varying respective capacitances;
measuring a total capacitance of the array of capacitive elements;
determining a difference between the measured total capacitance of the array of capacitive elements and a baseline total capacitance of the array of capacitive elements;
determining, using a computing device and based on the determined difference, a particular capacitive element exhibiting a capacitance variation; and
providing an indication of a position of the particular capacitive element within the flexible sensor.

18. The method of claim 17 , further comprising measuring the baseline total capacitance of the array of capacitive elements.

19. The method of claim 17 , wherein determining, based on the determined difference, the particular capacitive element exhibiting the capacitance variation comprises:
referring to a capacitance variation data structure to determine the particular capacitive element corresponding to the determined difference, wherein the capacitance variation data structure correlates capacitance variations to individual capacitive elements of the array of capacitive elements.

20. The method of claim 17 , wherein providing the indication of the position of the particular capacitive element within the flexible sensor comprises wirelessly communicating the indication to another device.

Assignees

• Boeing Co

Inventors

• Smith Robert A

Classifications

• G01N27/24 Primary

  Investigating the presence of flaws · CPC title

• G01N27/221

  by investigating the dielectric properties (using microwaves G01N22/00; measuring loss factors or dielectric constants per se G01R27/26) · CPC title

• G01N27/226

  Construction of measuring vessels; Electrodes therefor · CPC title

• G01R17/16

  with discharge tubes or semiconductor devices in one or more arms of the bridge, e.g. voltmeter using a difference amplifier · CPC title

• G01R27/26

  Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants {; Measuring impedance or related variables} · CPC title