Methods and apparatus to determine integrity of composite structures
AssigneeThe Boeing Company
InventorEugene A. Dan-Jumbo
Life of this patent
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Abstract
Apparatus and methods to determine structural integrity of composites are described herein. One described example method for determining sufficiency of structural integration of a composite structure for an aircraft includes applying a fluid droplet to a surface of the composite structure, determining a three-dimensional contact angle between the surface and a portion of the droplet, comparing the three-dimensional contact angle to a threshold angle, and determining whether the structural integration of the composite structure is sufficient based on the comparison.
Claims20
A method for determining a bond strength of a composite structure for an aircraft, the method comprising:
- applying a fluid droplet to a surface of the composite structure;
- determining a three-dimensional contact angle between the surface and a portion of the droplet;
- comparing the three-dimensional contact angle to a threshold angle;
- and
- determining whether the bond strength is sufficient based on the comparison, wherein a value of the three-dimensional contact angle of less than a predetermined threshold angle of about 10 degrees between the surface of the composite structure and the portion of the fluid droplet is indicative of the composite structure having sufficient bond strength to provide a pre-predetermined load bearing capacity.
An aircraft component that requires fewer fasteners, comprising:
- an external skin having a bonded composite structure, defining a skin surface area of an aircraft;
- a support frame;
- and
- an adhesive applied to the composite structure to attach the external skin to the support frame,
- wherein the composite structure has sufficient bond strength to enable adhesive attachment of the external skin to the support frame with less than 0.50 fasteners to couple the skin and the support frame per square-foot of the skin surface area, where a three-dimensional contact angle between the composite structure and a portion of a fluid droplet applied to the surface of the composite structure is less than a pre-determined threshold angle of about 10 degrees is indicative of sufficient bond strength.
A tangible machine readable medium having instructions stored thereon, which when executed, cause a machine to:
- determine a three-dimensional contact angle of a droplet placed onto a surface of a composite structure based on a measured diameter and volume of the droplet;
- compare the three-dimensional contact angle to a threshold angle of about 10 degrees,
- wherein the three-dimensional contact angle being less than the threshold angle indicates sufficient bond strength of the composite structure, and
- wherein the three-dimensional contact angle being greater than the threshold angle indicates insufficient bond strength of the composite structure;
- and
- output whether the composite structure has sufficient bond strength.
Dependencies are inferred from the claim text.