Systems and methods for inspecting electrical conductivity in composite materials

• US 7,312,608 B2
• Filed: 11/03/2005
• Issued: 12/25/2007
• Est. Priority Date: 11/03/2005
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Georgeson, Gary E., Westerman, Everett A., Hafenrichter, Joseph L.
• Primary Examiner(s): Deb; Anjan
• Assistant Examiner(s): He; Amy
• Application Number:
  US11/266,052
• Publication Number:
  US 20070096751A1
• Time in Patent Office: 782 Days
• Field of Search: 324/234, 324/691, 324/237, 324/238, 324/240, 324/525
• US Class Current: 324/240
• CPC Class Codes: G01N 27/9046 by analysing electrical signals
• CPC Class Codes: G01N 33/442 Resins; Plastics
• CPC Class Codes: G01R 27/2623 Measuring-systems or electronic circuits G01R27/2635, G01R27/2682 take precedence

Abstract

Systems and methods for inspecting electrical conductivity in composite materials having conductive structures are disclosed. In one embodiment, a system of inspecting electrical conductivity in an electrical bonding region includes a coil coupled to an alternating current source that is configured to induce a current in a conductive structure within the region. A processor is coupled to the coil that is operable to detect an impedance property value from the coil that results from the current induced in the conductive structure.

Claims

1. A system of inspecting electrical conductivity, comprising:

a coil coupled to an alternating current source and configured to induce a current in a conductive structure within the region;

a processor coupled to the coil that is operable to detect at least an impedance property value from the coil that results from the current induced in the conductive structure;

a conductive bonding region, the conductive bonding region further comprises a first composite portion having a first conductive layer, a second composite portion adjacent to the first composite portion and having a second conductive layer, and an intermediate conductive layer that forms an electrically conductive path extending between the first conductive layer and the second conductive layer; and

a compliant base portion including a foamed material, the compliant base portion disposed on the coil and configured to conform to a surface contour of the conductive bonding region.

2. The system of claim 1, wherein the alternating current source further comprises a source that is operable to excite the coil at a frequency that ranges between approximately about 50 Hertz (Hz) and approximately about 10 megahertz (MHz).

3. The system of claim 1, wherein the alternating current source further comprises a source that is operable to sequentially excite the coil at more than a single frequency.

4. The system of claim 3, wherein the alternating current source further comprises a source that is operable to generate a selected pair of frequencies, further wherein the selected pair of frequencies have a frequency ratio that ranges between approximately about 2:

1 and approximately about 4;

1.

5. The system of claim 1, wherein the coil further comprises a diameter, and the conductive bonding region further comprises a width, further wherein the diameter is at least approximately equal to the width.

6. The system of claim 1, wherein the detected impedance property value comprises at least one of a resistance, a reactance, a phasor magnitude and a phase angle.

7. The system of claim 1, wherein the foamed material further includes one of a foamed natural rubber and a foamed synthetic rubber.

8. The system of claim 1, wherein the first conductive layer, the second conductive layer and the intermediate conductive layer are comprised of at least one of a metallic woven mesh, a metallic foil, a flame sprayed metallic coating, a fabric that is coated with a metallic coating, and a metallic decal.