Moisture detection system

• US 10,422,742 B2
• Filed: 10/18/2017
• Issued: 09/24/2019
• Est. Priority Date: 10/18/2017
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Safai, Morteza, Wang, Xiaoxi
• Primary Examiner(s): Porta, David P
• Assistant Examiner(s): Riddick, Blake C
• Application Number:
  US15/787,201
• Publication Number:
  US 20190113450A1
• Time in Patent Office: 706 Days
• Field of Search: 2503381, 2503391, 25033901, 25033906
• CPC Class Codes: G01N 21/3554 for determining moisture content
• CPC Class Codes: G01N 22/04 Investigating moisture content
• CPC Class Codes: G01N 2201/0696 Pulsed
• CPC Class Codes: G01N 25/72 Investigating presence of flaws

Abstract

A method and system for an aerospace vehicle. A pulse of electromagnetic radiation is transmitted into the composite sandwich panel such that the composite sandwich panel is heated above an ambient temperature. An amount of infrared radiation generated in the composite sandwich panel is detected in response to transmitting the pulse of electromagnetic radiation into the composite sandwich panel using a time window selected to detect the amount of infrared radiation when the pulse of electromagnetic radiation heats the composite sandwich panel. The amount of infrared radiation detected indicates a level of moisture in the composite sandwich panel.

Claims

1. A moisture detection system comprising:

an electromagnetic radiation system;

an infrared detector system; and

a controller in communication with the electromagnetic radiation system and the infrared detector system, wherein the controller is configured to control the electromagnetic radiation system to transmit a pulse of electromagnetic radiation in which the pulse of electromagnetic radiation has multiple wavelengths that are absorbed by water molecules, wherein the multiple wavelengths penetrate a composite sandwich panel at a plurality of depths, and a depth at which moisture is present is determined according to wavelength; and

control the infrared detector system to detect an amount of infrared radiation in response to transmitting the pulse of electromagnetic radiation using a time window, wherein the amount of infrared radiation indicates a level of moisture.

2. The moisture detection system of claim 1, wherein the controller is configured to control the electromagnetic radiation system to transmit a pulse of electromagnetic radiation into the composite sandwich panel;

and control the infrared detector system to detect an amount of infrared radiation in response to transmitting the pulse of electromagnetic radiation into the composite sandwich panel using the time window selected to detect the amount of infrared radiation when the pulse of electromagnetic radiation heats the composite sandwich panel such that the infrared detector system detects the amount of infrared radiation in the composite sandwich panel when the composite sandwich panel is heated by the pulse of electromagnetic radiation, wherein the amount of infrared radiation indicates the level of moisture in the composite sandwich panel.

3. The moisture detection system of claim 2, wherein the controller is configured to control the infrared detector system to detect an amount of background infrared radiation prior to the electromagnetic radiation system transmitting the pulse of electromagnetic radiation.

4. The moisture detection system of claim 3, wherein the controller is configured to determine the level of moisture in the composite sandwich panel using the amount of infrared radiation detected and energy in the pulse of electromagnetic radiation sent into the composite sandwich panel.

5. The moisture detection system of claim 2, wherein the time window is selected to detect the amount of infrared radiation in response to the pulse of electromagnetic radiation heating the composite sandwich panel such that a sensitivity of the infrared detector system is increased.

6. The moisture detection system of claim 2, wherein the controller is configured to select a number of frequencies for the pulse of electromagnetic radiation based on a desired depth at which the pulse of electromagnetic radiation penetrates the composite sandwich panel.

7. The moisture detection system of claim 2, wherein the controller is configured to generate at least one of a thermal map or a thermal image of infrared radiation for the composite sandwich panel using the amount of infrared radiation detected by the infrared detector system within the time window.

8. The moisture detection system of claim 2, wherein the controller is configured to control the electromagnetic radiation system to transmit the pulse of electromagnetic radiation through a lens antenna to form an electromagnetic radiation beam directed at the composite sandwich panel such that the composite sandwich panel is heated above an ambient temperature for the composite sandwich panel.

9. The moisture detection system of claim 2, wherein the pulse of electromagnetic radiation has a number of frequencies selected from about 300 MHz to about 300 GHz.

10. The moisture detection system of claim 2, wherein the composite sandwich panel comprises a first face sheet, a second face sheet, and a core located between the first face sheet and the second face sheet, wherein the core is selected from at least one of a foam core, an open cell foam core, a closed cell foam core, or a honeycomb core.

11. The moisture detection system of claim 2, wherein the composite sandwich panel is for an aerospace vehicle, which is selected from one of an airplane, an aircraft, a commercial airplane, a rotorcraft, a spacecraft, a commercial spacecraft, and a space plane.

12. A method for detecting moisture in a composite sandwich panel for an aerospace vehicle, the method comprising:

transmitting a pulse of electromagnetic radiation into the composite sandwich panel such that the composite sandwich panel is heated above an ambient temperature, wherein the pulse of electromagnetic radiation has multiple wavelengths such that the pulse penetrates the composite sandwich panel at a plurality of depths, and a depth at which moisture is present is determined according to wavelength; and

detecting an amount of infrared radiation generated in the composite sandwich panel in response to transmitting the pulse of electromagnetic radiation into the composite sandwich panel using a time window selected to detect the amount of infrared radiation when the pulse of electromagnetic radiation heats the composite sandwich panel, wherein the amount of infrared radiation detected indicates a level of moisture in the composite sandwich panel.

13. The method of claim 12 further comprising:

determining the level of moisture in the composite sandwich panel using the amount of infrared radiation detected and energy in the pulse of electromagnetic radiation sent into the composite sandwich panel.

14. The method of claim 12 further comprising:

selecting the time window to detect the amount of infrared radiation when the pulse of electromagnetic radiation heats the composite sandwich panel above the ambient temperature such that a sensitivity of an infrared detector system is increased.

15. The method of claim 12 further comprising:

selecting a number of frequencies for the pulse of electromagnetic radiation based on a desired depth at which the pulse of electromagnetic radiation penetrates the composite sandwich panel.

16. The method of claim 12 further comprising:

generating a thermal image of the amount of infrared radiation for the composite sandwich panel using the amount of infrared radiation detected in the time window.

17. The method of claim 12, further comprising performing an action with respect to the composite sandwich panel, the action comprising

transmitting additional electromagnetic radiation into the composite sandwich panel such that the level of moisture inside of the composite sandwich panel is reduced.

18. The method of claim 12, further comprising performing an action, wherein the action is selected from one of reworking the composite sandwich panel and replacing the composite sandwich panel.

19. The method of claim 12, wherein transmitting the pulse of electromagnetic radiation into the composite sandwich panel comprises:

transmitting the pulse of electromagnetic radiation through a lens antenna to form a pulse of electromagnetic radiation beam directed at the composite sandwich panel such that the composite sandwich panel is heated above the ambient temperature for the composite sandwich panel.

20. The method of claim 12, wherein the transmitting and detecting steps are performed while the composite sandwich panel is installed in the aerospace vehicle.

21. The method of claim 12, wherein the transmitting and detecting steps are performed prior to installation of the composite sandwich panel in the aerospace vehicle.

22. The method of claim 12, wherein the pulse of electromagnetic radiation has a number of frequencies selected from about 300 MHz to about 300 GHz.

23. The method of claim 12, wherein the composite sandwich panel comprises a first face sheet, a second face sheet, and a core located between the first face sheet and the second face sheet, wherein the core is selected from at least one of a foam core, an open cell foam core, a closed cell foam core, or a honeycomb core.

24. The method of claim 12, wherein the aerospace vehicle is selected from one of an airplane, an aircraft, a commercial airplane, a rotorcraft, a spacecraft, a commercial spacecraft, and a space plane.

25. A moisture detection system comprising:

an electromagnetic radiation system;

an infrared detector system configured to detect an amount of infrared radiation; and

a controller configured to control the electromagnetic radiation system to transmit a pulse of electromagnetic radiation into a porous material in which a pulse of electromagnetic radiation beam has multiple wavelengths that are absorbed by water molecules such that the pulse penetrates the porous material at a plurality of depths, and a depth at which moisture is present is determined according to wavelength;

control the infrared detector system to detect the amount of infrared radiation in the porous material in response to transmitting the pulse of electromagnetic radiation into the porous material using a time window that captures when the pulse of electromagnetic radiation heats the porous material such that the infrared detector system detects the amount of infrared radiation in the porous material when the porous material is heated by the pulse of electromagnetic radiation; and

identify a level of moisture in the porous material using an amount of energy in the pulse of electromagnetic radiation transmitted and the amount of infrared radiation detected.

26. The moisture detection system of claim 25, wherein the controller selects a number of frequencies for the pulse of electromagnetic radiation based on a desired depth at which the pulse of electromagnetic radiation penetrates a composite sandwich panel.

27. The moisture detection system of claim 25, wherein the porous material is selected from a group comprising a composite panel, a composite sandwich panel, and a monument for an interior of an aerospace vehicle.

28. A method for detecting moisture in a porous material, the method comprising:

transmitting electromagnetic radiation into the porous material, wherein an electromagnetic radiation beam has multiple wavelengths that are absorbed by water molecules such that the electromagnetic radiation beam penetrates the porous material at a plurality of depths, and a depth at which moisture is present is determined according to wavelength; and

detecting an amount of infrared radiation in the porous material in response to transmitting the electromagnetic radiation into a composite sandwich panel using a time window selected to detect the amount of infrared radiation when the electromagnetic radiation heats the porous material; and

identifying a level of moisture in the porous material using an amount of energy in the electromagnetic radiation transmitted and the amount of infrared radiation detected.

29. The method of claim 28, wherein the porous material is selected from a group comprising a composite panel, the composite sandwich panel, and a monument for an interior of an aerospace vehicle.

30. The method of claim 28 further comprising:

selecting the time window to detect the amount of infrared radiation when the electromagnetic radiation heats the porous material above an ambient temperature such that a sensitivity of an infrared detector system is increased.

31. The method of claim 28 further comprising:

selecting a number of frequencies for a pulse of the electromagnetic radiation based on a desired depth at which the electromagnetic radiation penetrates the composite sandwich panel.