Thermoplastic composite structures embedded with at least one load fitting and methods of manufacturing same
Manufacturing a thermoplastic composite tubular structure embedded with a first load fitting comprising the steps of braiding a first plurality of inner layers of thermoplastic composite material around a soluble, expandable mandrel. A first load fitting is positioned on the first plurality of inner layers of thermoplastic composite material. A second plurality of outer layers of thermoplastic composite material is braided around the first load fitting and the mandrel so as to form an overbraided mandrel embedded with the first load fitting. The overbraided mandrel is installed into a matched tooling assembly and heated at a specified heating profile in order to consolidate the first plurality of inner layers of thermoplastic composite material and the second plurality of outer layers of thermoplastic composite material with the first load fitting so as to form a thermoplastic composite tubular structure embedded with the first load fitting. A second load fitting may be positioned on the first plurality of inner layers of thermoplastic composite material.
1. A thermoplastic composite tubular structure embedded with a first load fitting, comprising:
a first plurality of inner layers of thermoplastic composite material braided around a mandrel,
the mandrel comprising a soluble, expandable material and comprising a mandrel cross-section defining a first closed geometric shape;
the first load fitting placed on the first plurality of inner layers of thermoplastic composite material, wherein the first load fitting comprises a main body and a clevis that extends from a central portion of the main body, the first load fitting treated with an adhesion promoter prior to placing the loading fitting on the first plurality of inner layers; and
a second plurality of outer layers of thermoplastic composite material overbraided around the main body of the first load fitting and the mandrel so as to form an overbraided mandrel embedded with the first load fitting.
2. The thermoplastic composite tubular structure of claim 1 , wherein the soluble, expandable material of the mandrel is selected from the group consisting of one or more of ceramic, sand, a polymer binder, a soluble organic binder, a soluble inorganic binder, sodium silicate, graphite, one or more additives, and one or more preservatives.
3. The thermoplastic composite tubular structure of claim 1 , wherein the first closed geometric shape is selected from the group consisting of a circle, a semi-circle, a rectangle, an oval, an ellipse, a parallelogram, a trapezoid, a rhombus, a curvilinear triangle, a crescent, a quadrilateral, a quatrefoil, and a polygon comprising a triangle, a square, a pentagon, a hexagon, a heptagon, an octagon, a nonagon, a decagon, a hendecagon, and a dodecagon.
4. The thermoplastic composite tubular structure of claim 1 , wherein the first closed geometric shape is a circle.
5. The thermoplastic composite tubular structure of claim 1 , wherein the plurality of inner layers of thermoplastic composite material are materials selected from the group consisting of carbon fiber composite material; carbon fiber reinforced polymer material including carbon fiber reinforced polyphenylene sulfide (PPS), carbon fiber reinforced polyetheretherketone (PEEK), carbon fiber reinforced polyetherketoneketone (PEKK), and carbon fiber reinforced polyetherimide (PEI); and nylon.
6. The thermoplastic composite tubular structure of claim 5 , wherein the plurality of outer layers comprise the same type of material as the plurality of inner layers.
7. The thermoplastic composite tubular structure of claim 5 , wherein the plurality of outer layers comprise a different type of material as the plurality of inner layers.
8. The thermoplastic composite tubular structure of claim 1 , wherein the plurality of inner layers of thermoplastic composite material are in a form selected from the group consisting of a continuous slit tape thermoplastic composite material, a prepreg unidirectional tape, a prepreg fabric, a commingled fiber material, and a quasi-isotropic or anisotropic continuous fiber thermoplastic composite material.
9. The thermoplastic composite tubular structure of claim 1 , wherein the plurality of outer layers of thermoplastic composite material overbraided around the main body of the first load fitting and the mandrel is tailored to a depth relating to a type and magnitude of a load being introduced to the thermoplastic composite tubular structure embedded with the first load fitting.
10. The thermoplastic composite tubular structure of claim 1 , wherein the first plurality of inner layers comprises a first braided configuration; and the second plurality of outer layers comprises a second braided configuration.
11. The thermoplastic composite tubular structure of claim 10 , wherein the first braided configuration is different than the second braided configuration.
12. The thermoplastic composite tubular structure of claim 10 , wherein the first braided configuration is the same as the second braided configuration.
13. The thermoplastic composite tubular structure of claim 12 , wherein the first braided configuration and the second braided configuration comprise a biaxial braided configuration.
14. The thermoplastic composite tubular structure of claim 12 , wherein the first braided configuration and the second braided configuration comprise a triaxial braided configuration.
15. The thermoplastic composite tubular structure of claim 10 , wherein the first braided configuration comprises a biaxial braided configuration and the second braided configuration comprises a triaxial braided configuration.
16. The thermoplastic composite tubular structure of claim 1 , wherein the first load fitting comprises a metallic material selected from the group consisting of titanium, carbon composite, aluminum, and stainless steel.
17. The thermoplastic composite tubular structure of claim 1 , further comprising a second load fitting.
18. The thermoplastic composite tubular structure of claim 17 , wherein the second load fitting is placed on the first plurality of inner layers of thermoplastic composite material.
19. The thermoplastic composite tubular structure of claim 17 , wherein the first load fitting and the second load fitting are aligned with one another.
20. The thermoplastic composite tubular structure of claim 17 , wherein the first load fitting and the second load fitting are offset from one another.