Nondestructive multispectral vibrothermography inspection system and method therefor

Patent metadata

Field	Value
Publication number	US-11047819-B2
Application number	US-201815904966-A
Country	US
Kind code	B2
Filing date	Feb 26, 2018
Priority date	Feb 26, 2018
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

A nondestructive multispectral vibrothermography inspection system includes a fixture to retain a component, an ultrasonic excitation source directed toward the component retained within the fixture, a laser Doppler vibrometer directed toward the component retained within the fixture, and a multispectral thermography system directed toward the component retained within the fixture. A method for nondestructive multispectral vibrothermography inspection of a component, includes generating ultrasonic excitations in a component over a broad range of frequencies; determining a spectral signature in the component from the excitations; comparing the spectral energy signature against database 270 of correlations between vibrational frequencies of a multiple of components and the spectral energy distribution thereof, and classifying the component based on the database data.

First claim

What is claimed is:

1. A nondestructive multispectral vibrothermography inspection system to inspect a component without removal of a coating thereon, the system comprising:
a fixture to retain a component;
an ultrasonic excitation source directed toward the component to generate ultrasonic excitations in the component over a plurality of excitation frequencies between 20 kHz to 2 MHz;
a sensor directed toward the component to measure the natural vibrational modes of the component as surface velocity generated by the ultrasonic excitations;
a multispectral thermography system directed toward the component to determine a spectral signature in the component from the excitations, wherein the multispectral thermography system comprises a plurality of a near infrared (NIR) module, a short-wave infrared (SWIR) module, a mid-wave infrared (MWIR) module, a long-wave infrared (LWIR) module, and a very long-wave infrared (VLWIR) module, the spectral signature from 0.5 to 22 μm in wavelength, one for each of the plurality of ultrasonic excitation frequencies to provide a relation between the vibrational stresses in the component to the spectral signature;
a controller operable to classify the component based on a correlation between the surface velocities from the excitations and the spectral signature in the component from the excitations;
a database of the correlations between vibrational frequencies of a multiple of components and the spectral signature thereof; and
an image recognition algorithm to match the spectral signature of the component against a database that contains the spectral signature of previously inspected components known to have either failed or passed the inspection.

2. The system as recited in claim 1 , wherein the fixture comprises dampers that minimize the effect of the fixture in response to ultrasonic excitation from the ultrasonic excitation source.

3. The system as recited in claim 1 , wherein the multispectral thermography system is operable to view radiation over a range of the spectral signature.

4. The system as recited in claim 1 , wherein the spectral signature is from 0.5 to 14.5 μm in wavelength.

5. The system as recited in claim 1 , wherein the database of the correlations is utilized to score a component being inspected.

6. The system as recited in claim 1 , wherein the component comprises an airfoil.

7. The system as recited in claim 1 , further comprising one or more beam splitters to view the component through a single lens.

8. The system as recited in claim 1 , wherein the fixture comprises rubber pins that minimize the effect of the fixture in response to ultrasonic excitation from the ultrasonic excitation source.

9. A method for nondestructive multispectral vibrothermography inspection of a component without removal of a coating thereon, the method comprising:
generating ultrasonic excitations in a component over a plurality of frequencies from 20 kHz to 2 MHz;
determining a spectral signature in the component from the excitations, wherein the multispectral thermography system comprises a near infrared (NIR) module, a short-wave infrared (SWIR) module, a mid-wave infrared (MWIR) module, a long-wave infrared (LWIR) module, and a very long-wave infrared (VLWIR) module, the spectral signature is from 0.5 to 22 μm in wavelength, one for each of the plurality of ultrasonic excitation frequencies to provide a relation between the vibrational stresses in the component to the spectral signature;
determining a correlation between the surface velocities from the excitations and the spectral signature in the component from the excitations;
comparing the correlation against a database that contains the spectral signature of previously inspected components known to have either failed or passed the inspection; and
classifying the component based on the spectral signature.

10. The method as recited in claim 9 , wherein classifying the component comprises identifying whether the component is acceptable or unacceptable.

11. The method as recited in claim 9 , wherein classifying the component comprises scoring the component.

12. The method as recited in claim 9 , further comprising damping the component within a fixture.

13. The method as recited in claim 9 , wherein contact between the ultrasonic excitation source and the component under inspection induces elastic waves in the component, each single frequency of excitation is converted into a broad band of frequencies which are particular to resonant frequencies of the component.

14. The method as recited in claim 9 , wherein a classification algorithm for classifying the component based on the spectral signature learns from a ground truth database that is updated incrementally as additional ground truth data becomes available.

Assignees

• United Technologies Corp
• Raytheon Tech Corp

Inventors

• Martin Thomas J
• Staroselsky Alexander
• Finn Alan Matthew

Classifications

• G01N29/043 Primary

  in the interior, e.g. by shear waves · CPC title

• G01N29/4481

  Neural networks · CPC title

• G01N2291/0237

  Thin materials, e.g. paper, membranes, thin films · CPC title

• G01N29/2418

  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) · CPC title

• G01N29/069

  Defect imaging, localisation and sizing using, e.g. time of flight diffraction [TOFD], synthetic aperture focusing technique [SAFT], Amplituden-Laufzeit-Ortskurven [ALOK] technique · CPC title