Method for Fabricating Composite Porosity Standards

• US 20140346405A1
• Filed: 05/27/2013
• Published: 11/27/2014
• Est. Priority Date: 05/27/2013
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Ferguson, Kathy L., Spalding, John F.
• Granted Patent: US 9,140,673 B2
• Time in Patent Office: Days
• US Class Current: 252/408.1
• CPC Class Codes: G01N 15/088 Investigating volume, surface area, size or distribution of pores; Porosimetry
• CPC Class Codes: G01N 2001/2893 Preparing calibration standards
• CPC Class Codes: G01N 29/30 Arrangements for calibrating or comparing, e.g. with standard objects
• CPC Class Codes: Y10T 436/10 Composition for standardization, calibration, simulation, stabilization, preparation or preservation; processes of use in preparation for chemical testing
• CPC Class Codes: Y10T 436/109163 Inorganic standards or controls

Abstract

A method for fabricating composite porosity standards may include the steps of providing a plurality of uncured composite coupons, each uncured composite coupon being formed from a composite material, providing a plurality of curing processes, selecting a curing process for each of the uncured composite coupons, curing each uncured composite coupon in accordance with a selected curing process to form a plurality of cured composite coupons, each cured composite coupon being formed from the composite material and having a percent porosity, measuring the percent porosity of each cured composite coupon, and correlating each measured percent porosity of a plurality of measure percent porosities to a corresponding cured composite coupon of the plurality of cured composite coupons to form a plurality of porosity standards.

Claims

1. A method for fabricating a composite porosity standard, said method comprising:

selecting a curing process for an uncured composite coupon;

curing said uncured composite coupon in accordance with said selected curing process to form a cured composite coupon;

measuring a percent porosity of said cured composite coupon; and

correlating said measured percent porosity to said cured composite coupon to form a porosity standard.

2. The method of claim 1 further comprising providing a plurality of curing processes, wherein said selecting step comprises selecting said curing process from said plurality of curing processes.

3. The method of claim 1 wherein said uncured composite coupon comprises a composite material.

4. The method of claim 1 wherein said cured composite coupon has a percent porosity.

5. A method for fabricating composite porosity standards, said method comprising:

providing a plurality of uncured composite coupons, each uncured composite coupon of said plurality of uncured composite coupons comprising a composite material;

providing a plurality of curing processes;

selecting a curing process of said plurality of curing processes for each of said uncured composite coupons;

curing each uncured composite coupon of said plurality of uncured composite coupons in accordance with a selected curing process of said plurality of curing processes to form a plurality of cured composite coupons, each cured composite coupon of said plurality of cured composite coupons comprising said composite material having a percent porosity;

measuring said percent porosity of each cured composite coupon of said plurality of cured composite coupons; and

correlating each measured percent porosity of a plurality of measured percent porosities to a corresponding cured composite coupon of said plurality of cured composite coupons to form a plurality of porosity standards.

6. The method of claim 5 wherein each porosity standard of said plurality of porosity standards represents a measured percent porosity of said composite material.

7. The method of claim 5 wherein said selected curing process comprises at least one of a low exothermic autoclave curing process, a standard autoclave curing process, a low exothermic heat blanket curing process under double vacuum debulk, a low exothermic oven curing process under double vacuum debulk, a standard heat blanket curing process under double vacuum debulk, a standard oven curing process under double vacuum debulk, a low exothermic heat blanket curing process under high vacuum, a low exothermic oven curing process under high vacuum, a standard heat blanket curing process under high vacuum, a standard oven curing process under high vacuum, a low exothermic heat blanket curing process under standard vacuum, a low exothermic oven curing process under standard vacuum, a standard heat blanket curing process under standard vacuum, and a standard oven curing process under standard vacuum.

8. The method of claim 5 further comprising:

correlating each measured percent porosity of said plurality of measure percent porosities to a corresponding selected curing process of said plurality of curing processes;

ranking said plurality of curing processes based on a correlated measured percent porosity of said selected curing process; and

creating a porosity tree representing said plurality of curing processes as ranked from a lowest correlated measured percent porosity to a highest correlated measured percent porosity.

9. The method of claim 5 wherein said step of selecting said curing process of said plurality of curing processes for each of said uncured composite coupons is based on a porosity tree, said porosity tree representing said plurality of curing processes as ranked from a lowest measured percent porosity achieved to a highest measured percent porosity achieved.

10. The method of claim 5 further comprising evaluating a porosity consistency throughout each cured composite coupon of said plurality of cured composite coupons.

11. The method of claim 10 wherein said porosity consistency of each cured composite coupon of said plurality of cured composite coupons is measured by ultrasonic testing.

12. The method of claim 5 wherein said measured percent porosity of each cured composite coupon of said plurality of cured composite coupons is measured by imaging analysis.

13. The method of claim 12 wherein said imaging analysis comprises Image-J analysis.

14. The method of claim 12 wherein said imaging analysis comprises computed tomography.

15. The method of claim 5 further comprising providing a composite component comprising a composite material, wherein said composite material of said plurality of cured composite coupons is substantially the same as said composite material of at least a portion of said composite component.

16. The method of claim 15 further comprising:

evaluating an attenuation of said composite component;

evaluating an attenuation of at least one porosity standard of said plurality of porosity standards;

comparing attenuation measurements of said composite component to attenuation measurements of said at least one porosity standard; and

validating a percent porosity of said composite component.

17. The method of claim 5 wherein said composite material comprises a composite lay-up comprising at least two plies.

18. The method of claim 5 wherein said composite material comprises a prepreg material.

19. The method of claim 18 wherein said prepreg material comprises BMS8-340.

20. The method of claim 5 wherein said composite material comprises a wet lay-up material.

21. The method of claim 20 wherein said wet lay-up material comprises EA 9390.

22. A composite porosity reference standard comprising:

a cured composite coupon comprising a composite material having a percent porosity, said percent porosity being a result of a selected curing process on said composite material; and

a measured percent porosity of said cured composite coupon.

23. The standard of claim 22 wherein said composite material comprises a prepreg material.

24. The standard of claim 22 wherein said composite material comprises a wet lay-up material.