Method and apparatus for determining electrical properties of structures

• US 20050139001A1
• Filed: 09/24/2004
• Published: 06/30/2005
• Est. Priority Date: 04/16/2002
• Status: Active Grant

• Current Assignee: Mide Technology Corporation (Totalenergies Se)
• Original Assignee: Mide Technology Corporation (Totalenergies Se)
• Inventors: Lengyel, Attila, van Schoor, Marthinus, Cutler, Andrew M., Muller, Gert J., Radighieri, Brooks
• Granted Patent: US 7,167,009 B2
• Time in Patent Office: Days
• US Class Current: 73/159
• CPC Class Codes: G01L 1/205 using distributed sensing elements
• CPC Class Codes: G01M 5/0025 of elongated objects, e.g. pipes, masts, towers or railways G01M5/0058 takes precedence
• CPC Class Codes: G01M 5/0041 by determining deflection or stress

Abstract

A method and apparatus for determining an electrical property of a structure. The method involves creating a model of an electrical property of a structure and measuring the electrical property of the structure between at least two of a plurality of locations. The method also involves determining the electrical property of at least a portion of the structure based on the model and the measurement of the electrical property between the at least two of the plurality of locations.

Claims

1. A method of determining an electrical property of a structure, comprising:

creating a model of an electrical property of a structure;

measuring the electrical property of the structure between at least two of a plurality of locations; and

determining the electrical property of at least a portion of the structure based on the model and the measurement of the electrical property between the at least two of the plurality of locations.

2. The method of claim 1, comprising providing a plurality of electrical contacts to the structure.

3. The method of claim 1 wherein the electrical property is selected from the group consisting of resistance, capacitance and inductance.

4. The method of claim 1 wherein the electrical property is a combination of two or more electrical properties selected from the group consisting of resistance, capacitance and inductance.

5. The method of claim 1 wherein the plurality of locations are located on a boundary of the structure.

6. The method of claim 1 wherein the model is a lumped parameter model.

7. The method of claim 1 wherein the model is an analytical model.

8. The method of claim 1 wherein the model is a measurement-based model.

9. The method of claim 7 wherein the analytical model is a Volpe model.

10. The method of claim 1 wherein the model comprises a grid array of electrical nodes.

11. The method of claim 1 wherein the at least a portion of the structure is internal to a boundary of the structure.

12. The method of claim 1 wherein an internal resistance of the structure is determined.

13. The method of claim 12 wherein the internal resistance of the structure is used to determine location and severity of damage to the structure.

14. The method of claim 1 wherein a severity of damage is determined based on the electrical property of the at least a portion of the structure.

15. A system for determining an electrical property of a structure, comprising:

a model of an electrical property of a structure; and

a measuring device for measuring an electrical property of the structure between at least two of a plurality of locations and for determining the electrical property of at least a portion of the structure based on the model and the measurement of the electrical property between the at least two of the plurality of locations.

16. The system of claim 15, comprising a digital signal processor for selectively measuring electrical resistance between the at least two of the plurality of locations.

17. The system of claim 15 wherein the electrical property is selected from the group consisting of resistance, capacitance and inductance.

18. The system of claim 15 wherein the plurality of locations are located on a boundary of the structure.

19. The system of claim 15 wherein the model is selected from the group consisting of a lumped parameter model, an analytical model and a measurement-based model.

20. The system of claim 15 wherein the model comprises a grid array of electrical nodes.

21. The system of claim 15 wherein the at least a portion of the structure is internal to a boundary of the structure.

22. The system of claim 15 wherein an internal resistance of the structure is determined.

23. The system of claim 22 wherein the internal resistance of the structure is used to determine location and severity of damage to the structure.

24. The system of claim 15 wherein severity of damage to the structure is determined based on the electrical property of the at least a portion of the structure.

25. A system for determining an electrical property of a structure, comprising:

means for measuring an electrical property of the structure between at least two of a plurality of locations; and

means for determining the electrical property of at least a portion of the structure based on a model of the electrical property of the structure and the measurement of the electrical property between the at least two of the plurality of locations.

26. An analysis method for determining an electrical property of a structure, comprising:

measuring at least one electrical property between each of a plurality of locations of a structure;

forming a matrix comprising the electrical properties measured between each of the plurality of locations;

calculating the derivative of the matrix with respect to each of the electrical property measurements; and

estimating resistance of the structure between each of the locations based on the derivative of the matrix.

27. The method of claim 26 wherein estimating the resistance of the structure comprises applying an iteration method for solving a system of non-linear equations.

28. The method of claim 27 wherein the iteration method is a Newton-Raphson method.

29. The method of claim 26 wherein measuring at least one electrical property comprises applying a voltage at one of the locations of the structure and measuring the at least one electrical property relative to each other location of the plurality of locations of the structure.

30. The method of claim 29 comprising applying a voltage at a second location of the structure and measuring the at least one electrical property relative to each other location of the plurality of locations of the structure.

31. The method of claim 26 wherein the at least one electrical property is one or more of resistance, capacitance and inductance.

32. A system for determining an electrical property of a structure, comprising:

a measuring device for measuring at least one electrical property between each of a plurality of locations of a structure; and

an electrical device for calculating the derivative of a matrix with respect to each of the electrical property measurements and estimating resistance of the structure between each of the locations based on the derivative of the matrix, wherein the matrix is formed from the electrical properties measured between each of the plurality of locations.

33. The system of claim 32, comprising a digital signal processor for calculating the derivative of the matrix with respect to each of the electrical property measurements.

34. The system of claim 33 wherein the digital signal processor applies an iteration method to solve a system of non-linear equations to estimate the resistance of the structure between each of the locations.

35. The system of claim 34 wherein the iteration method is a Newton-Raphson method.

36. The system of claim 32 wherein the electrical property is selected from the group consisting of resistance, capacitance and inductance.

37. The system of claim 32 wherein the measuring device measures the at least one electrical property by applying a voltage at one of the locations of the structure and measuring the at least one electrical property relative to each other location of the plurality of locations of the structure.

38. A system for determining an electrical property of a structure, comprising:

means for measuring at least one electrical property between each of a plurality of locations of a structure;

means for forming a matrix comprising the electrical properties measured between each of the plurality of locations;

means for calculating the derivative of the matrix with respect to each of the electrical property measurements; and

means for estimating resistance of the structure between each of the locations based on the derivative of the matrix.