Abstract: A lightweight structure for containing fluid under pressure, the structure having no inner seal sheath and including a cylindrical zone formed with a single sheath consisting of a composite material which avoids microcracking phenomena provided by differential pressure existing betweeen an environment surrounding the structure and the pressure of the fluid within the structure. The sealed sheath remains sealed up to a pressure that is very close to the burst pressure of the structure. The composite material is made up of a polyamide 12 matrix and of carbon fibers embedded in the matrix to withstand longitudinal and transverse components of the differential pressure.

Abstract: The present invention relates to a method for forming a pipe with a corrugated wall by means of the electroforming technique. The method comprises the stage of forming, possibly partial, on the circumference of the pipe over a length of about one pitch of the corrugation. The corrugated deformation of the pipe is obtained by step-by-step forming after moving the forming mandrel longitudinally in the pipe. The invention also relates to a device for forming a corrugated pipe. In a variant, the device comprises a cylindrical mandrel on which a groove deepens over a circumference portion and continues at the depth of the corrugation to be formed.

Abstract: The present invention relates to a method and to a device for manufacturing parts made from resin and reinforcing fibers by winding. Molding means including a plurality of female forms corresponding each to a print of the part to be manufactured are produced. The forms are arranged one after the other, substantially helically, so as to make a continuous groove, then said groove is filled by winding with fibers coated with a polymerizable resin by rotating the prints round the axis of the helix.