NON-DESTRUCTIVE OPTICAL METHOD FOR DETERMINING MINIMUM BOND STRENGTH AND PROVING BOND EFFICACY

• US 20190017810A1
• Filed: 07/12/2017
• Published: 01/17/2019
• Est. Priority Date: 07/12/2017
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: HUMFELD, Keith D., KUTSCHA, Eileen
• Granted Patent: US 10,228,237 B2
• Time in Patent Office: Days
• CPC Class Codes: B64F 5/60 Testing or inspecting aircraft components or systems
• CPC Class Codes: G01B 11/16 for measuring the deformation in a solid, e.g. optical strain gauge
• CPC Class Codes: G01B 11/165 by means of a grating deformed by the object

Abstract

A method for determining a strain includes bonding first and second components together, at an elevated temperature, using a bonding agent. A strain is then measured in the first component using a strain measurement tool as the first component cools from the elevated temperature. The strain measurement tool is configured to detect movement the first component as the first component cools.

Claims

1. A method for determining a strain, comprising:

bonding first and second components together, at an elevated temperature, using a bonding agent; and

measuring a strain in the first component using a strain measurement tool as the first component cools from the elevated temperature, wherein the strain measurement tool is configured to detect movement the first component as the first component cools.

2. The method of claim 1, further comprising applying a visual indicator material to the first component, wherein the strain measurement tool detects movement of particles in the visual indicator material as the first component cools.

3. The method of claim 2, further comprising comparing the strain to a reference standard.

4. The method of claim 2, wherein the first component and the second component have different coefficients of thermal expansion.

5. The method of claim 4, wherein the first component and the second component have different strengths.

6. A method for determining a strain, comprising:

applying a visual indicator material to a first component;

applying a bonding agent to the first component;

pressing the first component and a second component together with the bonding agent positioned at least partially therebetween;

heating the first component and the bonding agent;

cooling the first component and the bonding agent; and

measuring a strain in the first component using a strain measurement tool, wherein the strain measurement tool is configured to detect movement of the visual indicator material on the first component as the first component cools.

7. The method of claim 6, wherein the visual indicator material is applied to the first component outside a bond area of the first component.

8. The method of claim 6, wherein the visual indicator material comprises a liquid having a plurality of particles dispersed therein, wherein the particles are a different color than the liquid.

9. The method of claim 6, wherein the first component and the bonding agent are heated to a predetermined temperature from about 105°

C. to about 125°

C., and wherein the first component and the bonding agent are heated to the predetermined temperature from about 80 minutes to about 100 minutes.

10. The method of claim 6, wherein the strain is measured without applying any external forces to the first component.

11. The method of claim 6, wherein the strain is a result only of deformation of the first component, the second component, or both due to a temperature change.

12. The method of claim 6, further comprising determining a stress in the first component based at least partially upon the strain and a modulus of a material of the first component.

13. The method of claim 12, further comprising comparing the stress to a reference standard.

14. A method for determining a strain, comprising:

applying a visual indicator material to a first component and a second component, wherein the first and second components have different coefficients of thermal expansion;

applying a bonding agent to the first component, the second component, or both;

pressing the first component and the second component together with the bonding agent positioned at least partially therebetween;

heating the first component, the second component, and the bonding agent;

cooling the first component, the second component, and the bonding agent after heating the first component, the second component, and the bonding agent; and

measuring a strain in the first component, the second component, or both using a strain measurement tool without applying external forces to the first component and the second component, wherein the strain measurement tool detects movement of particles in the visual indicator material as the first component, the second component, or both deform in response to the cooling.

15. The method of claim 14, wherein the different coefficients of thermal expansion are in a direction parallel to a surface of the first component having the bonding agent applied thereto.

16. The method of claim 14, wherein the bonding agent at least partially overlaps the visual indicator material.

17. The method of claim 14, wherein the visual indicator material is applied to the first component and the second component outside a bond area.

18. The method of claim 17, further comprising comparing the strain at a first location proximate to the bond area to the strain at a second location distal to the bond area.

19. The method of claim 14, further comprising determining a stress in the first component, the second component, or both based at least partially upon the strain and a modulus of a material of the first component, the second component, or both.

20. The method of claim 19, further comprising comparing the strain, the stress, or both to a reference standard to determine whether a strength of a bond between the first and second components is greater than or equal to a predetermined standard.