Methods and systems for detecting flaws in an object

• US 9,964,503 B2
• Filed: 10/21/2013
• Issued: 05/08/2018
• Est. Priority Date: 10/19/2012
• Status: Active Grant

• Current Assignee: Resodyn Corporation
• Original Assignee: Resodyn Corporation
• Inventors: Lucon, Peter A., Farrar, Lawrence C.
• Primary Examiner(s): Laballe, Clayton E
• Assistant Examiner(s): Rhodes, Jr., Leon W
• Application Number:
  US14/434,039
• Publication Number:
  US 20150253266A1
• Time in Patent Office: 1,660 Days
• Field of Search: 374 5
• 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:

exciting the object at a resonant frequency of the object to determine a plurality of resonant anti-node locations on the object to place a plurality of acoustic energy sources;

applying a static preload between respective contact points of the plurality of acoustic energy sources and the object such that the static preload prevents decoupling between the plurality of acoustic energy sources and the object when the object is excited;

applying acoustic energy to the determined plurality of resonant anti-node locations on the object to excite the object at a respective resonant frequency of the object associated with the respective determined plurality of resonant anti-node locations;

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 at least one of the plurality of anti-node locations comprises at least one of analyzing a resonant response of the object or determining a sufficient number of locations such that substantially the entire surface of the object is excited as an anti-node.

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

4. The method of claim 1, wherein at least one of the plurality of acoustic energy sources is placed in contact with the object via an energy transfer material and a contact plate.

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

6. 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.

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

an infrared camera and an embedded temperature sensor.

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

a plurality of acoustic energy sources held to the object with a static preload that prevents decoupling between the acoustic energy source and the object when the object is excited, the plurality of acoustic energy sources configured to excite the object at a resonant frequency of the object;

a motion sensor configured to determine a plurality of resonant anti-node locations on the object while the object is excited by one or more of the plurality of acoustic energy sources;

a temperature sensor;

a function generator configured to cause the plurality of acoustic energy sources to apply acoustic energy to the determined plurality of resonant anti-node locations on the object at one or more respective resonant frequencies associated with the respective determined plurality of resonant anti-node locations; and

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

receive data indicative of the plurality of resonant anti-node locations on the object from the motion sensor to determine placement locations on the object for the plurality of acoustic energy sources;

receive, from the temperature sensor, data indicative of a thermal response of the object to the application of acoustic energy to the determined plurality of resonant anti-node locations at the one or more respective resonant frequencies; and

analyze the thermal response to identify flaws within the object.

9. The system of claim 8, wherein each of the acoustic energy sources is one of:

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

10. The system of claim 8, wherein the temperature sensor is an infrared camera.

11. The system of claim 8, further comprising an energy transfer material to facilitate transfer of acoustic energy from a contact plate to the surface of the object.

12. The system of claim 8, wherein the motion sensor is at least one of:

an accelerometer, a dynamic force gauge, a Doppler vibrometer, and wherein the processor is configured 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.

13. The system of claim 12, 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.

14. The system of claim 8, wherein the function generator is configured to generate different types of electrical waveforms such that each of the plurality of acoustic energy sources may simultaneously excite the object at different resonant frequencies of the object over the same or different time periods.

15. The system of claim 8, wherein the function generator is a component of the processor.

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

exciting the bond joint at a resonant frequency of the bond joint to determine a plurality of resonant anti-node locations on the bond joint to place a plurality of acoustic energy sources;

applying a static preload between a contact point of the plurality of acoustic energy sources and the bond joint such that the static preload prevents decoupling between the plurality of acoustic energy sources and the bond joint;

applying acoustic energy to the determined plurality of resonant anti-node locations on the bond joint to excite the bond joint at respective resonant frequencies associated with the respective determined resonant anti-node locations;

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.

17. The method of claim 16, wherein the acoustic energy is applied for a time ranging from about 1 second to about 10 minutes.

18. The method of claim 16, 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.

19. The method of claim 16, wherein analyzing the thermal response further comprises determining at least one of:

a depth of a defect, a size of a defect, or a location of a defect.

20. The method of claim 16, comprising detecting by at least one accelerometer a shockwave resulting from a failure of the bond joint in response to the applied acoustic energy.