3D braided composited tubes with throat sections and manufacture method thereof
A manufacture method of a three dimensional (3D) braided composite tube with a throat section includes: providing an assembled mandrel comprising an upper mandrel and a lower mandrel, and braiding an 3D braided inner layer on the upper mandrel; winding fiber yarns to form a fiber yarn layer over the 3D braided inner layer; tightening the 3D braided inner layer to the assembled mandrel by an appropriate tension force when winding; and infiltrating resin and increasing temperature to cure the resin for obtaining a composite tube with a narrower throat section. The present invention takes advantage of winding fiber yarn outer layer to keep the radius of the throat of the 3D braided inner layer to meet design requirement. Additionally, the hoop strength of the throat section is increased so that the metal shell can be made thinner to reduce the weight of the rocket nozzle.
1. A manufacture method of three dimensional (3D) braided composite tube with a throat section, comprising:
providing an assembled mandrel comprising an upper mandrel and a lower mandrel, wherein the assembled mandrel has a middle portion which is narrower than two ends of the tube,
separating the lower mandrel from the upper mandrel and braiding an 3D braided inner layer on the upper mandrel, then tightening the 3D braided inner layer to the upper mandrel by binding devices;
combining the lower mandrel with the upper mandrel, and fixing the lower mandrel to the upper mandrel by a fixing device, then tightening the 3D braided inner layer to the lower mandrel by another set of binding devices;
removing the binding devices at the middle portion of the assembled mandrel, followed by winding fiber yarns from the middle portion of the assembled mandrel toward two ends thereof to the end binding devices respectively to form a fiber yarn outer layer over the 3D braided inner layer; and
infiltrating resin into the 3D braided inner layer and the fiber yarn outer layer, and increasing temperature to cure the resin to obtain a composite tube.
2. The manufacture method of claim 1 , wherein one terminal of the throat section is coupled to a converge section, and another terminal of the throat section is coupled to a diverge section.
3. The manufacture method of claim 1 , wherein the resin is selected from a group comprising epoxy resin, phenolic resin and furan resin.
4. The manufacture method of claim 1 , wherein the method of infiltrating resin into the 3D braided inner layer and the fiber yarn outer layer is a resin transfer molding process.
5. The manufacture method of claim 1 , wherein the method of infiltrating resin into the 3D braided inner layer and the fiber yarn outer layer is a vacuum-assisted resin transfer molding process.