CORROSION INSPECTION AND MONITORING SYSTEM

• US 20100312493A1
• Filed: 04/29/2010
• Published: 12/09/2010
• Est. Priority Date: 04/29/2009
• Status: Active Grant

• Current Assignee: Innovital LLC, University of Maryland
• Original Assignee: Techno-Sciences Incorporated (Safran SA)
• Inventors: Purekar, Ashish S., Chen, Peter Che-Hung, Wereley, Norman Mark
• Granted Patent: US 8,285,495 B2
• Time in Patent Office: Days
• US Class Current: 702/35
• CPC Class Codes: G01N 17/02 Electrochemical measuring systems for weathering, corrosion or corrosion-protection measurement
• CPC Class Codes: G01N 2291/0258 Structural degradation, e.g. fatigue of composites, ageing of oils
• CPC Class Codes: G01N 29/075 by measuring or comparing phase angle measuring frequencies or phase angles per se G01R23/00, G01R25/00
• CPC Class Codes: G01N 29/2437 Piezoelectric probes
• CPC Class Codes: G01N 29/4409 by comparison

Abstract

A system for in-situ near-real-time detection and monitoring of corrosion in structures with the ability to directly track the presence and growth of corrosion on a structure by measurement of material loss in the structure attained by analysis of high frequency wave propagation dynamics. The Corrosion Inspection and Monitoring (CIM) system utilizes low-weight in-situ transducers and unique data reduction software for detection and monitoring of corrosion in structural systems in near real-time for corrosion related damage. The CIM system provides a corrosion monitoring and tracking tool that can be deployed in the field with the structural system, and no maintenance personnel are needed for corrosion analysis.

Claims

1. An apparatus for detection and monitoring of corrosion in a structure by direct measurement of material loss in the structure, comprising:

a microcontroller including memory;

a function generator in communication with said microcontroller for generating a high-frequency tone burst excitation signal;

a power amplifier connected to said function generator for conditioning the high-frequency tone burst excitation signal;

an actuator connected to said power amplifier and in contact with said structure for imparting each said conditioned high-frequency tone burst excitation signal into said structure as a wave packet to generate a mechanical disturbance into the structure;

a plurality of sensors mounted on said structure for sensing mechanical deformation in said structure due to said wave packet wave propagation and for converting said mechanical deformation into voltage feedback signals;

an analog-to-digital converter connected between said plurality of sensors and said microcontroller for digitizing the feedback signals and transmitting the digitized signals to the microcontroller; and

software stored in said microcontroller memory for initiating said function generator to generate said high-frequency tone burst excitation signal, to extract phase and magnitude information from the digitized feedback signals from said analog-to-digital converter, and for correlating said phase and magnitude information with corrosion damage in said structure.

2. The CIM system of claim 1, wherein said plurality of sensors each further comprise a piezoelectric sensor element.

3. The CIM system of claim 1, wherein each said piezoelectric sensor element comprises a sensori-actuator piezoelectric element.

4. The CIM system of claim 3, wherein said actuator comprises a sensori-actuator piezoelectric element.

5. The CIM system of claim 1, wherein said plurality of sensors each further comprise a magnetostrictive sensor element.

6. The CIM system of claim 5, wherein said actuator comprises a magnetostrictive element.

7. The CIM system of claim 1, further comprising a multiplexer for selective reading of any one of said plurality of sensor elements.

8. A method for detection and monitoring of corrosion in a structure by direct measurement of material loss in the structure, comprising the steps of:

generating a high-frequency tone burst excitation signal;

amplifying said high-frequency tone burst excitation signal;

transmitting said high-frequency tone burst excitation signal to an actuator in contact with said structure and thereby imparting each said conditioned high-frequency tone burst excitation signal into said structure as a wave packet to generate a mechanical disturbance into the structure;

sensing mechanical deformation in said structure due to said wave packet wave propagation and converting said mechanical deformation into feedback signals;

digitizing the feedback signals;

extracting phase and magnitude information from the digitized feedback signals; and

correlating said phase and magnitude information with corrosion damage in said structure.

9. The method of claim 8, wherein said step of extracting phase and magnitude information from the digitized feedback signals further comprises the substeps of,

identifying a center frequency of the digitized feedback signals,

determining wave propagation group speed of the digitized feedback signals, and

processing said digitized feedback signals to determine phase and magnitude.

10. The method of claim 9, wherein said substep of processing said digitized feedback signals to determine phase and magnitude further comprises applying complex Fourier analysis.

11. The method of claim 9, wherein said substep of processing said digitized feedback signals to determine phase and magnitude further comprises applying complex Wavelet analysis.

12. The method of claim 8, wherein said step of correlating said phase and magnitude information with corrosion damage in said structure further comprises comparing said phase and magnitude information with baseline reference data.

13. The method of claim 8, wherein said step of correlating said phase and magnitude information with corrosion damage further comprises calculating an actual corrosion level in the structure.

14. An apparatus for detection and monitoring of corrosion in a structure by direct measurement of material loss in the structure, comprising:

a microcontroller including memory;

a function generator in communication with said microcontroller for generating an excitation signal;

an amplifier connected to said function generator for amplifying the excitation signal;

an actuator connected to said amplifier and in contact with said structure for imparting said excitation signal into said structure as a wave packet to generate a mechanical disturbance into the structure;

at least one sensor mounted on said structure for sensing mechanical deformation in said structure due to said wave packet wave propagation, and for generating a feedback signal there from; and

software stored in said microcontroller memory for extracting phase and magnitude information from the feedback signal and for correlating said phase and magnitude information with corrosion damage in said structure.

15. The CIM system of claim 14, wherein said at least one sensor comprises a plurality of sensors.

16. The CIM system of claim 15, wherein said plurality of sensors comprise at least one piezoelectric sensor element.

17. The CIM system of claim 16, wherein said sensori-actuator piezoelectric element also functions as said actuator.

18. The CIM system of claim 15, wherein said plurality of sensors further comprises at least one magnetostrictive sensor element.

19. The CIM system of claim 18, wherein said magnetostrictive sensor element also functions as said actuator.

20. The CIM system of claim 14, wherein said actuator comprises a magnetostrictive element.

21. The CIM system of claim 14, further comprising a multiplexer for selective reading of any one of said plurality of sensor elements