Method for creating non-inserted artificial disbonds or delaminations for nondestructive inspection test standards

Patent metadata

Field	Value
Publication number	US-9464965-B2
Application number	US-201414536218-A
Country	US
Kind code	B2
Filing date	Nov 7, 2014
Priority date	Nov 7, 2014
Publication date	Oct 11, 2016
Grant date	Oct 11, 2016

Abstract

A method for creation of a non-destructive inspection (NDI) standard employs a coupon of bonded layers or a composite structure having a predetermined thickness. A predetermined pulse width is defined. The coupon and a laser source are positioned with respect to one another and the laser source is used to create a laser pulse having the predetermined pulse width to create a disbond or delamination in the bond layer at a predetermined location. The coupon may then be used as a standard for calibration of NDI inspection tools by scanning the coupon with the tool to provide an inspection output. The output is then examined to confirm that the disbond or delamination in the coupon is properly identified in the output.

First claim

What is claimed is:

1. A method for creating a non-destructive inspection (NDI) standard, the method comprising:
selecting a coupon which is a laminate, said coupon having a predetermined thickness;
defining a predetermined pulse width;
positioning the coupon and a laser source relative to one another; and,
using the laser source to generate a laser pulse having the predetermined pulse width to impact a first surface of the coupon creating an impulse which travels through the coupon as a compression wave with a reflecting tension wave created from an opposing surface of the coupon, the reflecting tension wave propagation transmitted to a laminate layer as a weak point, resulting in a delamination or disbond at the laminate layer in an impact area to create at least one defect in the coupon, wherein the predetermined pulse width is shorter than a travel time of the laser pulse through the thickness of the coupon.

2. The method as defined in claim 1 wherein the laser source is controllable to produce a laser pulse with a controllable pulse width, beam shape and impulse power.

3. The method as defined in claim 1 wherein the laser pulse has a beam shape and wherein the beam shape produces a desired defect shape.

4. The method as defined in claim 3 wherein the laser pulse has an impulse power and wherein the impulse power produces a desired defect size.

5. The method as defined in claim 1 further comprising:
defining a predetermined path for sequentially positioning the laser source and the coupon relative to one another for creating a defect profile; and,
sequentially pulsing the laser source on the predetermined path to create the defect profile.

6. The method as defined in claim 1 wherein the coupon is a bonded coupon having a first layer and a second layer with an intermediate adhesive bond, and the step of using the laser source creates a disbond in the adhesive bond as the defect.

7. The method as defined in claim 1 wherein the coupon is a composite coupon and the step of using the laser source creates a delamination in the composite as the defect.

8. A method for calibrating a non-destructive inspection (NDI) tool comprising:
preparing a standard by
selecting a coupon which is a laminate having a predetermined thickness;
defining a predetermined pulse width;
positioning the coupon with respect to a laser;
controlling a laser source to create a laser pulse having the predetermined pulse width to impact a first surface of the coupon creating an impulse which travels through the coupon as a compression wave with a reflecting tension wave created from an opposing surface of the coupon, the reflecting tension wave propagation transmitted to a laminate layer as a weak point, resulting in a delamination or disbond at the laminate layer in an impact area to create at least one defect in the coupon at a known location;
using the standard that includes the at least one laser-produced defect therein, wherein the defect is in a known location;
scanning the standard with an NDI tool to produce an inspection output; and,
examining the inspection output to confirm that the at least one defect is identified at the known location in the standard.

9. The method as defined in claim 8 wherein the controllable laser source produces the laser pulse with a controllable pulse width, beam shape and impulse power.

10. The method as defined in claim 8 wherein the predetermined pulse width is shorter than a travel time of the laser pulse through the thickness of the coupon.

11. The method as defined in claim 10 wherein the step of preparing the standard further comprises:
defining a predetermined beam shape for a desired defect shape; and,
the step of controlling the laser source further comprises creating the laser pulse having the predetermined beam shape; and,
the step of examining the inspection output includes confirming the defect shape.

12. The method as defined in claim 11 wherein the step of preparing the standard further comprises:
defining a predetermined impulse power for a desired defect size; and,
the step of control the laser source further comprises creating the laser pulse having the predetermined impulse power; and,
the step of examining the inspection output includes confirming the defect size.

13. The method as defined in claim 12 wherein the step of preparing the standard further comprises:
defining a predetermined path for sequential positioning of the laser source with respect to the coupon for creating a defect profile; and,
the step of controlling the laser source further comprises sequentially pulsing the laser source on the predetermined path to create the defect profile; and,
the step of examining the inspection output includes confirming the defect profile.

14. An apparatus for creating a non-destructive inspection (NDI) standard comprising:
a coupon having a predetermined thickness;
a laser source capable of producing a laser pulse having a predetermined pulse width;
said coupon and the laser positioned with respect to one another to produce a defect at a known location in the coupon; and,
said laser source used to create the laser pulse having the predetermined pulse width to impact a first surface of the coupon creating an impulse which travels through the coupon as a compression wave with a reflecting tension wave created from an opposing surface of the coupon, the reflecting tension wave propagation transmitted to a laminate layer as a weak point, resulting in a delamination or disbond at the laminate layer in an impact area to create the at least one defect.

15. The apparatus as defined in claim 14 wherein the laser source produces a laser pulse with a controllable pulse width, beam shape and impulse power.

16. The apparatus as defined in claim 14 wherein the predetermined pulse width is shorter than a travel time of the laser pulse through the thickness of the coupon.

17. The apparatus as defined in claim 16 wherein:
a predetermined beam shape for the laser pulse is defined for a desired defect shape; and,
the laser source is controlled to create the laser pulse having the predetermined beam shape.

18. The apparatus as defined in claim 17 wherein:
a predetermined impulse power for the laser pulse is defined for a desired defect size; and,
said laser source further is controlled to create the laser pulse having the predetermined impulse power.

19. The apparatus as defined in claim 18 wherein:
the laser source is sequentially positionable along a predetermined path with respect to the coupon for creating a defect profile; and,
said laser source is sequentially pulsed on the predetermined path to create the defect profile.

Assignees

• Boeing Co

Inventors

• Bossi Richard H
• Stewart Alan F
• Piehl Marc J

Classifications

• G01N1/00 Primary

  Sampling; Preparing specimens for investigation · CPC title

• G01N35/00693

  Calibration · CPC title

• B29C59/16

  by wave energy or particle radiation {, e.g. infrared heating (B29C59/007 takes precedence)} · CPC title

• B29L2009/00

  Layered products · CPC title

• G01N19/04 Primary

  Measuring adhesive force between materials, e.g. of sealing tape, of coating · CPC title