Laser ultrasonic multi-component imaging

• US 7,876,453 B1
• Filed: 01/22/2008
• Issued: 01/25/2011
• Est. Priority Date: 01/22/2008
• Status: Active Grant

• Current Assignee: Battelle Energy Alliance LLC (Battelle Memorial Institute), The Boeing Co.
• Original Assignee: Battelle Energy Alliance LLC (Battelle Memorial Institute), The Boeing Co.
• Inventors: Williams, Thomas K., Telschow, Kenneth
• Primary Examiner(s): LEE, HWA S
• Application Number:
  US12/017,726
• Publication Number:
  US 20110030476A1
• Time in Patent Office: 1,099 Days
• Field of Search: 356/502, 356/432
• US Class Current: 356/502
• CPC Class Codes: G01N 2021/8438 Mutilayers
• CPC Class Codes: G01N 21/1702 with opto-acoustic detection, e.g. for gases or analysing solids
• CPC Class Codes: G01N 21/8422 Investigating thin films, e.g. matrix isolation method
• CPC Class Codes: G01N 2291/2694 Wings or other aircraft parts
• CPC Class Codes: G01N 29/0663 by acoustic holography acoustical holography per se G03H3/00
• CPC Class Codes: G01N 29/12 by measuring frequency or resonance of acoustic waves measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00
• CPC Class Codes: G01N 29/2418 using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics photoacoustic cells G01N21/1702; measuring characteristics of vibrations by using radiation-sensitive means G01H9/00; acousto-optical conversion techniques for short-range imaging G01S15/8965; sound-producing devices using laser bundle G10K15/046

Abstract

Techniques for ultrasonic determination of the interfacial relationship of multi-component systems are discussed. In implementations, a laser energy source may be used to excite a multi-component system including a first component and a second component at least in partial contact with the first component. Vibrations resulting from the excitation may be detected for correlation with a resonance pattern indicating if discontinuity exists at the interface of the first and second components.

Claims

1. A method for evaluating interface anomalies between components, the method comprising:

emitting a modulated laser beam at a multi-component system including a first component and a second component which is at least in partial contact with the first component, at least one of the first component and the second component being a fastener;

exciting at least a portion of the multi-component system via the modulated laser beam; and

detecting vibrations resulting from the exciting at least a portion of the multi-component system, the vibrations correlating to a resonance pattern indicating a discontinuity between the first component and the second component.

2. The method as described in claim 1, wherein the multi-component system is at least partially coated by at least one of a conversion coating, a base coating or a coating system made of more than one coating layer.

3. The method as described in claim 1, further comprising analyzing the resonance pattern to obtain at least one of a material strength orientation, a grain pattern, or a component anomaly for at least one of the system components.

4. The method as described in claim 1, wherein the exciting at least a portion of the multi-component system excites at least a portion of the multi-component system within the frequency range of between 0.5 MHz (zero point five mega hertz) to 100 MHz (one hundred mega hertz) and the resonance pattern is related to the detected vibrations in the nanometer range.

5. The method as described in claim 1, wherein:

the first component is the fastener and the second component is an outer skin material; and

the resonance pattern indicating a gap occurring at an interface between the fastener and the outer skin material.

6. The method as described in claim 1, wherein the detecting the vibrations detects the vibrations via a photorefractive crystal to present the resonance pattern in real-time.

7. The method as described in claim 1, wherein the resonance pattern is based on an out of plane vibration of the second component extending generally transversely, with respect to a plane defined by the first component.

8. The method as described in claim 6, wherein the presenting the resonance pattern in real-time presents the resonance pattern as a digital holographic image.

9. A method for identifying interface anomalies between vehicle components, the method comprising:

emitting a laser beam at a multi-component vehicle system including a fastener and an outer skin material;

exciting one or more of the fastener and the outer skin material via the laser beam;

detecting vibrations resulting from the exciting one or more of the fastener and the outer skin material; and

presenting a resonance pattern identifying a gap between the fastener and the outer skin material of the multi-component vehicle system, the resonance pattern based on the detected vibrations.

10. The method as described in claim 9, further comprising determining a size of the gap between the fastener and the outer skin material of the multi-component vehicle system.

11. The method as described in claim 9, further comprising splitting the laser beam into a reference beam and an energizing beam, the energizing beam directed at or more of the fastener and the outer skin material.

12. The method as described in claim 11, wherein the resonance pattern is further based on the reference beam.

13. The method as described in claim 9, wherein the multi-component vehicle system is an aerospace vehicle, the outer skin material is a material forming an outer surface of the aerospace vehicle, and the fastener secures the material forming the outer surface of the aerospace vehicle to a support component of the aerospace vehicle.

14. The method as described in claim 9, wherein the exciting one or more of the fastener and the outer skin material via the laser beam comprises one of:

exciting a region of the multi-component vehicle system including both the fastener and the outer skin material;

exciting only the fastener;

or

exciting only the outer skin material.

15. The method as described in claim 9, wherein the emitting the laser beam causes the fastener to vibrate out of plane with respect to a plane generally defined by the outer skin material.

16. The method as described in claim 9, wherein:

the detecting the vibrations detects the vibrations via a photorefractive crystal; and

the presenting the resonance pattern presents the resonance pattern in real-time as a digital holographic image.