Synchronized phased array and infrared detector system for moisture detection

• US 10,656,081 B2
• Filed: 10/18/2017
• Issued: 05/19/2020
• 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): Kim, Christine S.
• Application Number:
  US15/787,014
• Publication Number:
  US 20190113449A1
• Time in Patent Office: 944 Days
• CPC Class Codes: G01N 2021/1714 Photothermal radiometry with measurement of emission
• CPC Class Codes: G01N 21/3554 for determining moisture content
• CPC Class Codes: G01N 21/3563 for analysing solids; Preparation of samples therefor
• CPC Class Codes: G01N 21/71 thermally excited
• CPC Class Codes: G01N 2201/0696 Pulsed
• CPC Class Codes: G01N 25/56 by investigating moisture content
• CPC Class Codes: G01N 25/72 Investigating presence of flaws
• CPC Class Codes: Y02T 50/40 Weight reduction

Abstract

A method and system for detecting moisture in a composite sandwich panel for an aerospace vehicle. A pulse of an electromagnetic radiation beam is beam steered to the composite sandwich panel. The pulse of the electromagnetic radiation beam has a number of wavelengths that is absorbed by water molecules. The timing of the pulse of the electromagnetic radiation beam is synchronized to heat the composite sandwich panel with a time window in an infrared detector system to detect an amount of infrared radiation. The amount of infrared radiation in the composite sandwich panel is detected within the time window for the infrared detector system when the composite sandwich panel is heated by the pulse of the electromagnetic radiation beam, wherein the amount of infrared radiation 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 select a number of frequencies for a pulse of an electromagnetic radiation beam based on a desired depth at which the pulse of the electromagnetic radiation beam penetrates a composite sandwich panel;

control the electromagnetic radiation system to transmit the pulse of the electromagnetic radiation beam in which the pulse of the electromagnetic radiation beam has the number of frequencies that are absorbed by water molecules; and

control the infrared detector system to detect an amount of infrared radiation in response to transmitting the pulse of the electromagnetic radiation beam 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 amount of infrared radiation indicates a level of moisture in the composite sandwich panel for an aerospace vehicle and wherein the controller is configured to control a phased array to beam steer the pulse of the electromagnetic radiation beam emitted by the phased array to the composite sandwich panel;

synchronize timing of the pulse of the electromagnetic radiation beam to heat the composite sandwich panel with the time window used by the infrared detector system to detect the amount of infrared radiation; and

control the infrared detector system to detect the amount of infrared radiation in the composite sandwich panel within the time window when the composite sandwich panel is heated by the pulse of the electromagnetic radiation beam.

3. The moisture detection system of claim 2, wherein the controller controls the phased array to beam steer the pulse of the electromagnetic radiation beam to an area on the composite sandwich panel and controls the infrared detector system to detect the amount of infrared radiation from the area within the time window when the pulse of the electromagnetic radiation beam heats the area on the composite sandwich panel.

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

5. 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 the electromagnetic radiation beam.

6. The moisture detection system of claim 2, wherein the controller is configured to generate a thermal image of the amount of infrared radiation for the composite sandwich panel using energy in the pulse of the electromagnetic radiation beam and the amount of infrared radiation detected by the infrared detector system within the time window.

7. The moisture detection system of claim 2, wherein the controller is configured to generate a map of moisture within the composite sandwich panel using a thermal image.

8. 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 the electromagnetic radiation beam heating the composite sandwich panel such that a sensitivity of the infrared detector system is increased.

9. 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.

10. The moisture detection system of claim 2, wherein the composite sandwich panel for 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.

11. The moisture detection system of claim 1, wherein the number of frequencies selected from about 300 MHz to about 300 GHz.

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

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

transmitting the pulse of the electromagnetic radiation beam into the composite sandwich panel such that the composite sandwich panel is heated above an ambient temperature; and

detecting an amount of infrared radiation generated in the composite sandwich panel in response to transmitting the pulse of the electromagnetic radiation beam into the composite sandwich panel using a time window selected to detect the amount of infrared radiation when the pulse of the electromagnetic radiation beam 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:

beam steering the pulse of the electromagnetic radiation beam to an area on the composite sandwich panel; and

detecting the amount of infrared radiation in the composite sandwich panel within the time window for an infrared detector system when the area on the composite sandwich panel is heated by the pulse of the electromagnetic radiation beam.

14. The method of claim 13 further comprising:

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

15. The method of claim 12 further comprising:

detecting an amount of background infrared radiation prior to an electromagnetic radiation system transmitting the pulse of the electromagnetic radiation beam.

16. The method of claim 12 further comprising:

generating a thermal image of the amount of infrared radiation for the composite sandwich panel using energy in the pulse of the electromagnetic radiation beam and the amount of infrared radiation detected by an infrared detector system within the time window.

17. The method of claim 16 further comprising:

generating a map of the moisture within the composite sandwich panel using the thermal image.

18. The method of claim 12, wherein the time window is selected to detect the amount of infrared radiation in response to the pulse of the electromagnetic radiation beam heating the composite sandwich panel such that a sensitivity of an infrared detector system is increased.

19. 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.

20. 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.

21. 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 select a number of frequencies for a pulse of an electromagnetic radiation beam based on a desired depth at which the pulse of the electromagnetic radiation beam penetrates a composite sandwich panel;

control the electromagnetic radiation system to transmit the pulse of the electromagnetic radiation beam into a porous material in which the pulse of the electromagnetic radiation beam has the number of frequencies that are absorbed by water molecules;

control the infrared detector system to detect the amount of infrared radiation in the porous material in response to transmitting the pulse of the electromagnetic radiation beam into the porous material using a time window that captures when the pulse of the electromagnetic radiation beam 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 the electromagnetic radiation beam; and

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

22. The moisture detection system of claim 21, wherein the controller is configured to determine the level of moisture in the composite sandwich panel using the amount of infrared radiation detected in an area and energy in the pulse of the electromagnetic radiation beam sent into the area on the porous material.

23. The moisture detection system of claim 21, wherein the controller is configured to control the infrared detector system to detect an amount of background infrared radiation in an area prior to an electromagnetic radiation system transmitting the pulse of the electromagnetic radiation beam into the area on the porous material.

24. The moisture detection system of claim 21, wherein the controller is configured to generate a thermal image of the amount of infrared radiation for the porous material using energy in the pulse of the electromagnetic radiation beam and the amount of infrared radiation detected by the infrared detector system within the time window.

25. The moisture detection system of claim 21, wherein the controller is configured to generate a map of moisture within the porous material in an area using a thermal image.

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

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

transmitting the electromagnetic radiation beam into the porous material, wherein the electromagnetic radiation beam has the number of frequencies that are absorbed by water molecules;

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

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

27. The method of claim 26 further comprising:

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

28. The method of claim 26 further comprising:

detecting an amount of background infrared radiation in an area prior to an electromagnetic radiation system transmitting the pulse of the electromagnetic radiation beam into the area on the porous material.

29. The method of claim 26 further comprising:

generating a thermal image of the amount of infrared radiation for the porous material using energy in the pulse of the electromagnetic radiation beam and the amount of infrared radiation detected by an infrared detector system within the time window.