METHODS AND SYSTEMS FOR DETECTING FLAWS IN AN OBJECT

• US 20150253266A1
• Filed: 10/21/2013
• Published: 09/10/2015
• Est. Priority Date: 10/19/2012
• Status: Active Grant

• Current Assignee: Resodyn Corporation
• Original Assignee: Resodyn Corporation
• Inventors: Lucon, Peter A., Farrar, Lawrence C.
• Granted Patent: US 9,964,503 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01J 5/02 Constructional details
• CPC Class Codes: G01J 5/48 Thermography; Techniques using wholly visual means
• CPC Class Codes: G01N 2291/0231 Composite or layered materials
• CPC Class Codes: G01N 2291/0289 Internal structure, e.g. defects, grain size, texture
• CPC Class Codes: G01N 25/72 Investigating presence of flaws
• CPC Class Codes: G01N 29/069 Defect imaging, localisation and sizing using, e.g. time of flight diffraction [TOFD], synthetic aperture focusing technique [SAFT], Amplituden-Laufzeit-Ortskurven [ALOK] technique

Abstract

The present application is directed towards systems and methods for evaluating the integrity of objects through non-destructive means. The objects are evaluated for flaws and defects through the use of applied acoustic energy. The applied acoustic energy creates a dynamic response of the object being evaluated to determine the location of any flaws or defects in the object. During excitation, the flaws and defects in a sample object generate heat at the damaged or defective regions through frictional interactions of the discontinuities. A flaw detection system includes, a plurality of acoustic energy sources to excite an object, a camera to record metrics of the response of the object and a processor configured to receive and analyze the response of the object.

Claims

1. A method for detecting flaws in an object, the method comprising:

determining a location on the object to place an acoustic energy source;

applying a static preload between a contact point of the acoustic energy source and the object;

applying acoustic energy to excite the object;

recording a thermal response of the object to the application of acoustic energy; and

analyzing the thermal response to identify flaws within the object.

2. The method of claim 1, wherein determining the location comprises analyzing the resonant response of the object to identify anti-node locations.

3. The method of claim 1, wherein the determining the location comprises determining a sufficient number of locations such that substantially the entire surface of the object is excited as an anti-node.

4. The method of claim 1, wherein determining the location comprises visually identifying anti-node locations of the object while exciting the object at a resonant frequency of the object.

5. The method of claim 1, wherein the acoustic energy source is placed in contact with the object via an energy transfer material.

6. The method of claim 1, wherein the acoustic energy source is placed in contact with the object via an energy transfer material and a contact plate.

7. The method of claim 1, wherein the static preload is generated by a vacuum source.

8. The method of claim 1, wherein the static preload is greater than the dynamic force induced in the object by the acoustic energy source.

10. The method of claim 1, wherein applying the acoustic energy comprises applying the acoustic energy at a frequency ranging from about 100 Hz to about 60 kHz.

11. The method of claim 1, wherein the acoustic energy is applied for a time ranging from about 1 second to about 10 minutes.

12. The method of claim 1, wherein the thermal response is recorded by at least one of:

an infrared camera and an embedded temperature sensor.

13. The method of claim 1, wherein analyzing the thermal response comprises comparing an image of the object taken prior to exciting the object to an image of the object taken while the object is being excited to determine a transient response of the object.

14. The method of claim 1, analyzing the thermal response further comprises determining at least one of:

a depth of a defect, a size of a defect, and a location of the defect.

15. The method of claim 1, wherein the object includes a bond joint.

16. The method of claim 15, further comprising analyzing the bond joint to detect a disband or a delamination in the bond joint.

17. A system for detecting flaws in an object, the system comprising:

a plurality of acoustic energy sources;

a temperature sensor; and

a processor communicatively coupled to the temperature sensor, the processor configured to;

receive data indicative of a thermal response of the object to the application of acoustic energy applied to the objet by the plurality of acoustic energy sources; and

analyze the thermal response to identify and determine characteristics of flaws and defects in the object.

18. The system of claim 17, wherein each of the acoustic energy sources is one of:

a piezoelectric transducer, a voice coil, or a rotating eccentric mass.

19. The system of claim 17, wherein the temperature sensor is an infrared camera.

20. The system of claim 17, further comprising a contact plate to transfer acoustic energy from at least one acoustic energy source to the object.

21. The system of claim 17, further comprising an energy transfer material to facilitate transfer of acoustic energy from contact plate to the surface of the object.

22. The system of claim 21, wherein the energy transfer material is duct tape.

23. The system of claim 17, further comprising at least one of:

an accelerometer, a dynamic force gauge, a Doppler vibrometer, and wherein the processor is configure to process the output of the accelerometer, dynamic force gauge, or Doppler vibrometer to determine placement locations on the object for the plurality of acoustic energy sources.

24. The system of claim 23, wherein the processor is configured to generate and analyze thermal difference thermograms based on temperature data received from the temperature sensor before and during excitation of the object by the plurality of acoustic energy sources to determine a transient thermal response of the object.

25. A method for detecting flaws in a bond joint, the method comprising:

determining a location on the bond joint to place an acoustic energy source;

applying a static preload between a contact point of the acoustic energy source and the bond joint;

applying acoustic energy to excite the bond joint;

recording a thermal response of the bond joint to the application of acoustic energy; and

analyzing the thermal response to identify flaws within the bond joint.

26. The method of claim 25, wherein the acoustic energy source is placed in contact with the bond joint via an energy transfer material.

27. The method of claim 25, wherein the acoustic energy source is placed in contact with the bond joint via an energy transfer material and a contact plate.

28. The method of claim 25, wherein the static preload is generated by a vacuum source.

29. The method of claim 25, wherein the static preload is greater than the dynamic force induced in the bond joint by the acoustic energy source.

30. The method of claim 25, wherein applying the acoustic energy comprises applying the acoustic energy at a frequency ranging from about 100 Hz to about 60 kHz.

31. The method of claim 25, wherein the acoustic energy is applied for a time ranging from about 1 second to about 10 minutes.

32. The method of claim 25, wherein the thermal response is recorded by at least one of:

an infrared camera and an embedded temperature sensor.

33. The method of claim 25, wherein analyzing the thermal response comprises comparing an image of the bond joint taken prior to exciting the bond joint to an image of the bond joint taken while the bond joint is being excited to determine a transient response of the object.

34. The method of claim 25, analyzing the thermal response further comprises determining at least one of:

a depth of a defect, a size of a defect, and a location of the defect.

35. The method of claim 25, comprising detecting by at least one accelerometer a shockwave resulting from a failure of the bond joint in response to the applied acoustic energy.