Strength design of stainless steel threaded fittings

　　Stainless steel pipe is screwed on the bracket the large load of main bearing component. On stainless steel threaded pipe structure design and optimization, the stainless steel screw thread pipe fittings of preparation technology, axial pressure theoretical design and experimental analysis of the performance etc. were studied. Strength design is always a difficult and hot thread structure design of stainless steel pipe fittings. Whether it is the angle spread layers of stainless steel screw thread pipe fittings or axial / ring to cross ply laminated tube, proper content of ring to layer are able to significantly improve the tube axial compressive strength. The 20% of the angle ply （axial ply） changed to ring to layer after, winding angle for 20 DEG stainless steel screw thread pipe fittings of the axis compressive strength is improved by about one times, cross ply layer of stainless steel screw thread pipe fittings of axis compression strength also increased by more than 10%.

　　Through the corresponding finite element model for reusable vehicle verify the X-33 and Atlas V rocket composite thrust stand bearing capacity were analyzed and pointed out that the X-33 type thrust stand structure in the form of comprehensive carrying capacity is good, suitable for more complex loading conditions, and Atlas V type thrust stand structure form of compression bearing ability is good, suitable for high thrust loading conditions.