Sensing system for monitoring the structural health of composite structures

• US 7,921,727 B2
• Filed: 06/24/2005
• Issued: 04/12/2011
• Est. Priority Date: 06/25/2004
• Status: Active Grant

• Current Assignee: University of Dayton
• Original Assignee: University of Dayton
• Inventors: Rice, Brian P.
• Primary Examiner(s): Caputo; Lisa M
• Assistant Examiner(s): Kirkland, III; Freddie
• Application Number:
  US11/166,056
• Publication Number:
  US 20050284232A1
• Time in Patent Office: 2,118 Days
• Field of Search: 737/62, 737/63, 737/66, 737/74, 737/77, 737/95, 738/05
• US Class Current: 73/762
• CPC Class Codes: G01B 7/18 using change in resistance
• CPC Class Codes: G01M 5/0033 by determining damage, crack or wear
• CPC Class Codes: G01M 5/0083 by measuring variation of impedance, e.g. resistance, capacitance, induction
• CPC Class Codes: G01N 27/205 in insulating materials

Abstract

A sensing system for use in monitoring the structural health of a structure such as a polymeric matrix composite structure is provided. The system includes a sensor formed from a conductive ink containing carbon nanofibers and a polymeric resin, and a data acquisition system for acquiring and evaluating data from the sensor. The conductive ink may be applied directly to the structure to be monitored in the form of a grid pattern. Damage to the structure may be detected by measuring changes in resistance values detected from the sensor.

Claims

1. A sensing system for monitoring the structural health of a structure comprising:

a sensor comprising a conductive ink containing from about 4 to about 12% by weight vapor grown carbon nanofibers having a high aspect ratio and at least one polymeric resin; and

a data acquisition system;

wherein said sensor is applied in the form of a grid pattern directly to the surface of said structure.

2. The system of claim 1 wherein said data acquisition system comprises electrodes bonded to said sensor.

3. The system of claim 2 wherein said data acquisition system further includes a voltage meter.

4. The system of claim 1 wherein said structure is selected from a polymeric matrix composite structure, a metal structure, or a concrete structure.

5. The system of claim 1 wherein said structure comprises a polymeric matrix composite structure, and wherein said polymeric resin in said conductive ink is compatible with the polymer in said polymeric matrix composite structure.

6. A sensing system for monitoring the structural health of a polymeric matrix composite structure comprising:

a sensor comprising a conductive ink containing from about 4 to about 12% by weight vapor grown carbon nanofibers having a high aspect ratio and at least one polymeric resin which is compatible with said polymer in said polymeric matrix composite structure; and

a data acquisition system.

7. A method of monitoring the structural health of a structure comprising:

providing a sensor comprising a conductive ink containing from about 4 to about 12% by weight vapor grown carbon nanofibers having a high aspect ratio and at least one polymeric resin; and

applying said sensor to a structure to be monitored in the form of a grid pattern by painting, rolling, or spraying; and

providing a data acquisition system connected to said sensor for acquiring and evaluating data from said sensor.

8. The method of claim 7 wherein said structure is selected from a polymeric matrix composite structure, a metal structure, or a concrete structure.

9. The method of claim 7 wherein said structure comprises a polymeric matrix composite structure, and wherein said polymeric resin in said conductive ink is compatible with the polymer in said polymeric matrix composite structure.

10. The method of claim 7 wherein said structure comprises a polymeric matrix composite structure, and wherein said polymeric resin in said conductive ink is the same as the polymer in said polymeric matrix composite structure.

11. The method of claim 7 wherein said polymeric resin is selected from the group consisting of epoxy resins, polyimides, bismaleimides, cyanate esters, polyesters, vinyl esters, and urethanes.

12. The method of claim 7 wherein said data acquisition system comprises electrodes bonded to said sensor.

13. The method of claim 7 wherein said sensor is applied directly to said structure.

14. The method of claim 7 wherein said structure is electrically conductive.

15. The method of claim 14 including applying a nonconductive insulating coating to said structure prior to applying said sensor.