Inspection of structures

Patent metadata

Field	Value
Publication number	US-10126273-B2
Application number	US-201615056684-A
Country	US
Kind code	B2
Filing date	Feb 29, 2016
Priority date	Feb 29, 2016
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

A method of detecting inconsistencies in a structure is presented. A pulsed laser beam is directed towards the structure. A plurality of types of ultrasonic signals is formed in the structure when radiation of the pulsed laser beam is absorbed by the structure. The plurality of types of ultrasonic signals is detected to form data.

First claim

What is claimed is:

1. A method of detecting inconsistencies in a structure, the method comprising:
directing a pulsed laser beam towards the structure, wherein surface waves and shear waves are formed in the structure when radiation of the pulsed laser beam is absorbed by the structure; and
detecting the surface waves and the shear waves at a point detector to form data, wherein the point detector is formed on a surface of the structure.

2. The method of claim 1 , further comprising:
identifying a crack in the structure using the data representing the surface waves.

3. The method of claim 1 , wherein the surface waves are transmitted through a joint in the structure.

4. The method of claim 1 , further comprising:
identifying corrosion in the structure using data representing the shear waves.

5. The method of claim 1 , further comprising:
identifying inconsistencies on a far side of the structure using the data representing the shear waves.

6. The method of claim 1 , wherein the pulsed laser beam and the point detector are spaced apart such that both the surface waves and shear waves are detected.

7. The method of claim 1 , wherein the structure is a homogenous material.

8. The method of claim 1 , wherein the structure is formed of at least one of a composite, a metal, a ceramic, a polymeric material, a semi-conductor material, or a glass material.

9. The method of claim 1 , wherein the structure is a single layer.

10. The method of claim 1 , wherein directing the pulsed laser beam towards the structure comprises positioning a line pump perpendicular to a direction of a joint such that ultrasonic signals travel entirely through the joint when the point detector is positioned over the joint.

11. The method of claim 1 , wherein the point detector is significantly smaller than a distance between the pulsed laser beam and the point detector on the surface of the structure.

12. A method comprising:
directing a pulsed laser beam towards a structure, wherein the pulsed laser beam is a line on a surface of the structure, wherein a plurality of types of ultrasonic signals is formed in the structure when radiation of the pulsed laser beam is absorbed by the structure, and wherein the plurality of types of ultrasonic signals includes surface waves and shear waves;
detecting the plurality of types of ultrasonic signals to form data, wherein the plurality of types of ultrasonic signals are detected using a single point detector formed by an interferometer, wherein the pulsed laser beam and a single point detector are spaced apart such that the plurality of types of ultrasonic signals is detected by the single point detector; and
determining an inconsistency is present in the structure using the data.

13. The method of claim 12 , wherein the structure is formed of a single layer.

14. The method of claim 12 , wherein the inconsistency includes at least one of a joint inconsistency, corrosion, an inconsistency on a far side of the structure, or a crack.

15. The method of claim 12 , wherein directing the pulsed laser beam towards the structure comprises positioning the line on the surface of the structure perpendicular to a direction of a joint such that ultrasonic signals travel entirely through the joint when the single point detector is positioned over the joint.

16. The method of claim 12 , wherein the single point detector is significantly smaller than a distance between the pulsed laser beam and the single point detector on the surface of the structure.

17. An apparatus comprising:
a pulsed laser beam forming a line pump on a first surface of a structure; and
a pulsed laser beam forming a point detector on the first surface of the structure wherein the line pump and the point detector are spaced a distance apart, wherein the distance is selected such that the point detector detects surface waves and shear waves from the structure.

18. The apparatus of claim 17 , wherein the pulsed laser beam forming the line pump is provided by laser ultrasonic equipment.

Assignees

• Boeing Co
• Univ Washington

Inventors

• Pelivanov Ivan
• Motzer William P
• O'Donnell Matthew
• Brady Steven Kenneth
• Georgeson Gary Ernest
• Kollgaard Jeffrey Reyner
• Gordon Iii Clarence Lavere
• Bingham Jill Paisley
• Stewart Alan F
• Kennedy James C

Classifications

• G01N29/225

  Supports, positioning or alignment in moving situation · CPC title

• G01N29/07 Primary

  by measuring propagation velocity or propagation time of acoustic waves · CPC title

• G01N2291/0232

  Glass, ceramics, concrete or stone · CPC title

• G01N2291/2694

  Wings or other aircraft parts · CPC title

• G01N29/265

  by moving the sensor relative to a stationary material · CPC title