Acoustic emission sensor array

• US 9,151,733 B1
• Filed: 03/07/2012
• Issued: 10/06/2015
• Est. Priority Date: 03/07/2011
• Status: Expired due to Fees

• Current Assignee: North Carolina A&T State University (University of North Carolina System)
• Original Assignee: North Carolina A&T State University (University of North Carolina System)
• Inventors: Sundaresan, Mannur J.
• Primary Examiner(s): Martin, Laura
• Assistant Examiner(s): MILLER, ROSE MARY
• Application Number:
  US13/414,092
• Time in Patent Office: 1,308 Days
• Field of Search: 735/87
• US Class Current: 1/1
• CPC Class Codes: G01N 2291/0231 Composite or layered materials
• CPC Class Codes: G01N 2291/0421 Longitudinal waves
• CPC Class Codes: G01N 2291/0422 Shear waves, transverse waves, horizontally polarised waves
• CPC Class Codes: G01N 2291/0427 Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever
• CPC Class Codes: G01N 2291/106 one or more transducer arrays
• CPC Class Codes: G01N 2291/2694 Wings or other aircraft parts
• CPC Class Codes: G01N 29/07 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 29/14 using acoustic emission techniques echo of particles G01N29/046; measuring mechanical vibrations or acoustic waves in solids in general G01H1/00
• CPC Class Codes: G01N 29/2475 Embedded probes, i.e. probes incorporated in objects to be inspected
• CPC Class Codes: G01N 29/4427 with stored values, e.g. threshold values

Abstract

A sensor array for non-destructively monitoring a structure to detect a critical structural event. The sensor array includes at least one discrete AE sensor node for producing an electrical signal in response to a structural event and at least one shear wave sensor assembly. The shear wave sensor assembly includes at least one shear wave sensor. A gate module is connected to the at least one discrete AE sensor node and to the at least one shear wave sensor assembly, whereby the gate module is adapted to pass through the electrical signal from the at least one discrete AE sensor node in response to a pre-determined signal from the at least one shear wave sensor assembly. The sensor array may further include a signal processing module for receiving and processing the discrete AE sensor output signal. In addition, a data collection system may be located downstream of the signal processing module.

Claims

1. A sensor array for non-destructively monitoring a structure to detect a critical structural event, said sensor array comprising:

(a) at least one discrete AE sensor node for producing an electrical signal in response to a structural event;

(b) at least one shear wave sensor assembly, said shear wave sensor assembly including at least one pair of shear wave sensors, each shear wave sensor of said at least one pair of shear wave sensors having a length to provide a longitudinal axis of the shear wave sensor, and said at least one pair of shear wave sensors being oriented in a plane and at about a 90 degree angle with respect to one another along each sensor'"'"'s longitudinal axis;

(c) a gate module connected to said at least one discrete AE sensor node and to said at least one shear wave sensor assembly, whereby said gate module is adapted to pass through said electrical signal from said at least one discrete AE sensor node in response to a pre-determined signal from said at least one shear wave sensor assembly; and

(d) a signal processing module for receiving and processing said discrete AE sensor output signal.

2. The sensor array according to claim 1, further including a data collection system downstream of said signal processing module.

3. In a sensor array for non-destructively monitoring a structure to detect a critical structural event, said sensor array including at least one discrete AE sensor node for producing an electrical signal in response to a structural event and a signal processing module for receiving and processing said discrete AE sensor output signal, the improvement comprising:

(a) at least one shear wave sensor assembly, said shear wave sensor assembly including at least one pair of shear wave sensors, each shear wave sensor of said at least one pair of shear wave sensors having a length to provide a longitudinal axis of the shear wave sensor, and said at least one pair of shear wave sensors being oriented in a plane and at about a 90 degree angle with respect to one another along each sensor'"'"'s longitudinal axis; and

(b) a gate module connected to said at least one discrete AE sensor node and to said at least one shear wave sensor assembly, whereby said gate module is adapted to pass through said electrical signal from said at least one discrete AE sensor node in response to a pre-determined signal from said at least one shear wave sensor assembly.

4. The sensor array according to claim 3, wherein each of said pair of shear wave sensors oriented in a plane and at about a 90 degree angle with respect to one another include a plurality of discrete shear wave sensor nodes adjacent to one another, each of said discrete shear wave sensor nodes producing an electrical signal in response to a structural event.

5. The sensor array according to claim 4, wherein said plurality of discrete shear wave sensor nodes adjacent to one another are connected in series.

6. The sensor array according to claim 4, wherein said plurality of discrete shear wave sensor nodes are piezoceramic sensors.

7. The sensor array according to claim 6, wherein said piezoceramic sensors are formed into a strip having a length of about 10 mm and a width of about 1 mm.

8. The sensor array according to claim 7, wherein said piezoceramic sensors are active fiber composites.

9. The sensor array according to claim 7, wherein said piezoceramic sensors include a plurality of substantially parallel sensor strips.

10. The sensor array according to claim 9, wherein said plurality of substantially parallel sensor strips are substantially equal length.

11. The sensor array according to claim 10, wherein said plurality of substantially parallel sensor strips of substantially equal length are arranged in a rectangular shape.

12. The sensor array according to claim 10, wherein said plurality of substantially parallel sensor strips of substantially equal length are arranged in a parallelogram shape.

13. The sensor array according to claim 4, further including a signal adder electrically connected to said plurality of discrete shear wave sensor nodes, said signal adder receiving and combining said electrical signal from each of said discrete shear wave sensor nodes to form a single shear wave output signal from each pair of shear wave sensors oriented in a plane and at about a 90 degree angle with respect to one another.

14. The sensor array according to claim 3, further including a plurality of shear wave sensor assemblies, each of said shear wave sensor assemblies including at least one pair of shear wave sensors oriented in a plane and at about a 90 degree angle with respect to one another, wherein said plurality of shear wave sensor assemblies are adapted to form a guard array.

15. The sensor array according to claim 14, wherein said guard array is a guard ring.

16. The sensor array according to claim 3, wherein said gate module connected to said at least one discrete AE sensor node and to said at least one shear wave sensor assembly, whereby said gate module is adapted to pass through said electrical signal from said at least one discrete AE sensor node to said signal processing module in response to a pre-determined signal from said at least one shear wave sensor assembly further includes a sub-module for varying the value of said threshold of said pre-determined signal from said at least one shear wave sensor assembly.

17. A sensor array for non-destructively monitoring a structure to detect a critical structural event, said sensor array comprising:

(a) at least one discrete AE sensor node for producing an electrical signal in response to a structural event;

(b) at least one shear wave sensor assembly, said shear wave sensor assembly including a pair of shear wave sensors, each shear wave sensor of said at least one pair of shear wave sensors having a length to provide a longitudinal axis of the shear wave sensor, and said at least one pair of shear wave sensors being oriented in a plane and at about a 90 degree angle with respect to one another along each sensor'"'"'s longitudinal axis;

(c) a gate module connected to said at least one discrete AE sensor node and to said at least one shear wave sensor assembly, whereby said gate module is adapted to pass through said electrical signal from said at least one discrete AE sensor node in response to a pre-determined signal from said at least one shear wave sensor assembly;

(d) a signal processing module for receiving and processing said discrete AE sensor output signal; and

(e) a data collection system downstream of said signal processing module.

18. The sensor array according to claim 17, wherein the data collection system includes a database module.

19. The sensor array according to claim 18, further including an exception reporting module.

20. The sensor array according to claim 19, wherein said exception reporting module includes a sub-module for setting a predetermined threshold value and a sub-module for sending an alarm when the predetermined threshold value is met.