Method and system for measurement of current flows in fastener arrays

• US 7,532,000 B2
• Filed: 08/03/2006
• Issued: 05/12/2009
• Est. Priority Date: 08/03/2006
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Kovach, Daniel J., Robb, Andrew M.
• Primary Examiner(s): TANG, MINH NHUT
• Application Number:
  US11/498,634
• Publication Number:
  US 20080036448A1
• Time in Patent Office: 1,013 Days
• Field of Search: None
• US Class Current: 324/117.00H
• CPC Class Codes: G01R 15/181 using coils without a magnetic core, e.g. Rogowski coils
• CPC Class Codes: G01R 31/008 on air- or spacecraft, railway rolling stock or sea-going vessels

Abstract

A method and apparatus for simultaneously measuring current flows through fasteners in a multi-structure composite joint is provided. The method comprising inserting a printed circuit board between at least two structures, the printed circuit board being etched with at least one Rogowski coil sensory circuit the at least two structures being joined with at least one fastener extending through the at least one Rogowski coil sensory circuit in the printed circuit board; detecting current in the at least one fastener; transmitting the detected current from each fastener to a corresponding passive integrator circuit for capturing transient pulses and integrating the pulses into an output; and transmitting the output to a processing unit.

Claims

1. A method for measuring current flows through fasteners in a multi-structure composite joint, comprising:

inserting a printed circuit board between at least two structures, the printed circuit board being etched with at least one Rogowski coil sensory circuit, the two structures being joined with at least one fastener extending through the at least one Rogowski coil sensory circuit in the printed circuit board;

detecting current in the at least one fastener using the corresponding Rogowski coil;

transmitting the detected current from each fastener to a corresponding passive integrator circuit for capturing transient pulses and integrating the pulses into an output; and

transmitting the output to a processing unit.

2. The method of claim 1, wherein the at least two structures are joined by at least two fasteners, each fastener extending through a corresponding Rogowski coil sensory circuit, the captured transient pulses being transmitted to the corresponding passive integrator circuit, the integrator output from each passive integrator circuit being transmitted as an array output to the processing unit, for simultaneously measuring the current flows through the at least two fasteners.

3. The method of claim 2, wherein the fasteners are disposed normal to the printed circuit board.

4. The method of claim 1, wherein the processing unit is a network analyzer.

5. The method of claim 1, wherein the processing unit is an oscilloscope.

6. The method of claim 2, wherein the array output is used to at least one of certify an aircraft or to improve the design of aircraft structures in an aircraft to reduce damage to the aircraft caused by a lightning strike.

7. The method of claim 1, wherein the passive integrator circuit is comprised of at least one variable resistor connected to a capacitor for filtering out noise emanating from skin currents.

8. The method of claim 1, wherein the detected current is caused by an electrical pulse transmitted through the at least one fastener, and wherein the electrical pulse simulates a lightning strike.

9. A system for simultaneously measuring current flows through fasteners in a multi-structure composite joint, comprising:

a printed circuit board etched with at least two Rogowski coil sensory circuits, each Rogowski coil being wound in a double-helix pattern, the printed circuit board being inserted inside the joint between at least two structures joined with at least two fasteners, with the at least two fasteners each extending through a corresponding Rogowski coil sensory circuit;

a passive integrator array having at least two passive integrator circuits for receiving a corresponding output from each Rogowski coil sensory circuit and integrating the outputs into an array output; and

a processing unit for displaying the array output.

10. The system of claim 9, wherein the outputs are transient pulses from the printed circuit board caused by an electrical pulse transmitted through the at least two fasteners, and wherein the electrical pulse simulates a lightning strike.

11. The system of claim 10, wherein the fasteners are normal to the printed circuit board.

12. The system of claim 9, wherein the processing unit is a network analyzer.

13. The system of claim 9, wherein the processing unit is an oscilloscope.

14. The system of claim 9, wherein the array output is used to certify an aircraft for safety.

15. The system of claim 9, wherein the array output is used to improve the design on structures on an aircraft to prevent damage from a lightning strike.

16. The system of claim 9, wherein the passive integrator circuit filters noise emanating from skin currents.

17. The system of claim 9, wherein the passive integrator circuit comprises a variable resistor connected to a capacitor.