Method and assembly for bonding complex composite assemblies
A tooling assembly and method for bonding composite components together, such as a bonded cascade assembly of a thrust reverser for an aircraft nacelle. The method may include the steps of fixing composite turning vanes between elongated stiffeners, placing them in a cavity formed by a tooling frame, then filling cavities between the turning vanes, the elongated stiffeners, and/or the tooling frame with flowable solid elastomeric material. The method may also include the steps of compressing and/or heating the elastomeric material, the turning vanes, the elongated stiffeners, and the tooling frame. This heat and/or pressure combined with expansion of the elastomeric material may be sufficient to press contacting portions of the turning vanes and the elongated stiffeners toward each other and also causing the turning vanes to bond to the elongated stiffeners under pressure of the elastomeric material expansion.
1. A method of bonding multiple components of a composite assembly, the method comprising:
placing at least two composite components in contact with each other;
placing a pressure distribution plate with holes formed therethrough over at least a portion of the composite components;
filling cavities formed within or between the composite components with flowable solid elastomeric material by flowing the flowable solid elastomeric material through the holes formed in the pressure distribution plate;
compressing the elastomeric material, causing flow of the flowable solid elastomeric material to increase pressure applied by the elastomeric material against the composite components, thereby pressing the at least two composite components toward each other, causing the composite components to bond to each other under pressure of the elastomeric material; and
separating the pressure distribution plate from the portion of the composite components after the compressing step.
2. The method of claim 1 , further comprising placing the composite parts within a tooling frame prior to the step of filling the cavities with the elastomeric material.
3. The method of claim 1 , wherein at least one of the holes of the pressure distribution plate is aligned with at least one of the cavities.
4. The method of claim 1 , wherein the step of compressing the elastomeric material includes placing an impermeable membrane over the elastomeric material and sealing the impermeable membrane, then compressing the impermeable membrane toward the elastomeric material via application of a pressure differential.
5. The method of claim 1 , wherein the step of compressing the elastomeric material includes pressing a plunger or plate against the elastomeric material in a direction toward the composite components and the tooling frame.
6. The method of claim 2 , further comprising placing a coefficient of thermal expansion (CTE) insert between at least one of the composite components and the tooling frame to compensate for differences in coefficients of thermal expansion between the tooling frame and the composite components, wherein the CTE insert is made of a different material than the tooling frame and the composite components.
7. The method of claim 1 , wherein the step of fixing the composite components in contact with each other further comprises attaching at least one of the composite components to another one of the composite components using adhesive prior to the step of filling the cavities with the elastomeric material.
8. A method of bonding multiple components of a bonded cascade assembly of an aircraft nacelle, the method comprising:
fixing a plurality of turning vanes between a plurality of elongated stiffeners with adhesive, wherein the turning vanes and the elongated stiffeners are made of composite material;
placing the turning vanes and the elongated stiffeners within a tooling frame;
placing a pressure distribution plate with holes formed therethrough over at least a portion of the turning vanes and the elongated stiffeners;
filling cavities formed between the turning vanes and the elongated stiffeners with solid granules or particles of elastomeric material, wherein the holes in the pressure distribution plate are large enough to allow the granules or particles of the elastomeric material to flow therethrough and into the cavities during the step of filling the cavities with the elastomeric material;
compressing and heating the elastomeric material, the turning vanes, the elongated stiffeners, and the tooling frame, the compressing causing the elastomer to exert hydrostatic pressure sufficient to press contacting portions of the turning vanes and the elongated stiffeners toward each other and causing the turning vanes to bond to the elongated stiffeners under pressure provided by the elastomeric material; and
separating the pressure distribution plate from the portion of the turning vanes and the elongated stiffeners after the compressing and heating step.
9. The method of claim 8 , wherein at least one of the holes of the pressure distribution plate is aligned with one of the cavities.
10. The method of claim 8 , wherein the step of compressing the elastomeric material includes placing an impermeable membrane over the elastomeric material and sealing the impermeable membrane to the tooling frame, then compressing the impermeable membrane toward the tooling frame and the elastomeric material via application of a pressure differential.
11. The method of claim 8 , wherein the step of compressing the elastomeric material includes pressing a plunger or plate against the elastomeric material in a direction toward the turning vanes, the elongated stiffeners, and the tooling frame.
12. The method of claim 8 , further comprising placing a coefficient of thermal expansion (CTE) insert between at least one of the elongated stiffeners and the tooling frame to compensate for differences in coefficients of thermal expansion between the tooling frame and the elongated stiffeners, wherein the CTE insert is made of a different material than the tooling frame and the elongated stiffeners.
13. The method of claim 8 , wherein the turning vanes include two positioning flanges and a flow directing portion extending between the positioning flanges, wherein locations at which the positioning flanges contact the elongated stiffeners are bondlines, wherein the elastomeric material comprises granules or particles larger in diameter, thickness, or volume than a maximum space between the positioning flanges and the elongated stiffeners at the bondlines.
14. The method of claim 8 , wherein the step of heating involves heating the elastomeric material to a curing temperature of the adhesive.
15. The method of claim 8 , wherein the tooling frame comprises a plurality of heat transfer fins extending into the cavity formed by the tooling frame, wherein the turning vanes are positioned such that one or more of the heat transfer fins extend between two of the turning vanes placed into the tooling frame.