A multilayer structure for storing hydrogen, including, from the inside, at least one sealing layer and at least one composite reinforcement layer, an innermost composite reinforcement layer being welded to an outermost adjacent sealing layer, the sealing layers being a composition predominantly of: at least one semi-crystalline polyamide thermoplastic polymer P1i, i=1 to n, n being the number of sealing layers, excluding an amide polyether block (PEBA), up to 50% by weight of impact modifier relative to the total weight of the composition, up to 1.5% by weight of plasticizer relative to the total weight of the composition, and at least one of the composite reinforcement layers of a fibrous material in the form of continuous fibers, which is impregnated with a composition predominantly of at least one semi-crystalline polyamide polymer P2j, j=1 to m, m being the number of reinforcement layers.

This disclosure relates generally to corrugated pipe, and more particularly to corrugated pipe with an outer wrap. In one embodiment, a pipe includes an axially extended bore defined by a corrugated outer wall having axially adjacent, outwardly-extending corrugation crests, separated by corrugation valleys. The pipe also includes an outer wrap applied to the outer wall. The outer wrap may include fibers and plastic. The outer wrap may span the corrugation crests producing a smooth outer surface.

A pressure vessel includes a vessel body including a cylindrical-shaped straight body portion with a spiral-shaped projection portion formed at an outer peripheral surface of the straight body portion, and a covering portion that comprises a fiber bundle wrapped onto the outer peripheral surface of the straight body portion in a spiral pattern running parallel to the projection portion so as to cover the outer peripheral surface of the straight body portion.

A method for forming a composite fluid conduit includes providing an inner pipe having a variation in cross-section between at least two different longitudinal sections thereof and applying a fiber reinforced composite material to the inner pipe. In some disclosed examples the variation in cross section may be provided intermediate opposing ends of the inner pipe. In other disclosed examples the variation in cross section may be provided at an end region of the inner pipe.

A method for forming a composite fluid conduit includes providing an inner pipe having a variation in cross-section between at least two different longitudinal sections thereof and applying a fiber reinforced composite material to the inner pipe. In some disclosed examples the variation in cross section may be provided intermediate opposing ends of the inner pipe. In other disclosed examples the variation in cross section may be provided at an end region of the inner pipe.

A double-layer longitudinal wrapping mold is disclosed, including a base, a first longitudinal wrapping structure, a first pressing structure, a second longitudinal wrapping structure, a second pressing structure and a first necking structure. The first longitudinal wrapping structure is disposed on the base and has a first guide hole, a first outer layer wrapping hole and an inner layer wrapping hole. The first pressing structure is disposed on the base and has a first pressing hole and a second outer layer wrapping tape hole. The second longitudinal wrapping structure is disposed on the base and has a second guide hole and a third outer layer wrapping tape hole. The second pressing structure is disposed on the base and has a second pressing hole and a fourth outer layer wrapping tape hole. The first necking structure is disposed on the base and has a necking hole.

Multilayer structure for transporting hydrogen, including, from the inside, at least one sealing layer and at least one composite reinforcing layer, an innermost composite reinforcing layer being wound around an outermost adjacent sealing layer, the sealing layers of a composition predominantly of at least one semi-crystalline, long-chain polyamide thermoplastic polymer P1i (i=1 to n, n being the number of sealing layers), the Tf of which, as measured according to ISO 11357-3: 2013, is greater than 160° C., with the exception of one polyether block amide (PEBA), up to 50% by weight of impact modifier relative to the total weight of the composition and up to 1.5% by weight of plasticiser relative to the total weight of the composition, the composition being free of nucleating agent, and at least one of the composite reinforcing layers being of a fibrous material.

A multilayer structure for transporting hydrogen, including, from the inside, a sealing layer and at least one composite reinforcement layer, an innermost composite reinforcement layer being wound around the sealing layer, the sealing layer being a composition predominantly of: a polyamide thermoplastic polymer PA11, up to less than 15% by weight of impact modifier, up to 1.5% by weight of plasticizer relative to the total weight of the composition, the composition being devoid of nucleating agent and of polyether block amide (PEBA), and at least one of the composite reinforcement layers being a fibrous material in the form of continuous fibers, which is impregnated with a composition predominantly of at least one polymer P2j, (j=1 to m, m being the number of reinforcement layers), the structure being devoid of an outermost layer and adjacent to the outermost layer of a composite reinforcement layer made of a polyamide polymer.

This disclosure relates generally to corrugated pipe, and more particularly to corrugated pipe with an outer wrap. In one embodiment, a pipe includes an axially extended bore defined by a corrugated outer wall having axially adjacent, outwardly-extending corrugation crests, separated by corrugation valleys. The pipe also includes an outer wrap applied to the outer wall. The outer wrap may include fibers and plastic. The outer wrap may span the corrugation crests producing a smooth outer surface.

A hybrid piston pin and a manufacturing method thereof are provided. The hybrid piston pin includes a cylindrical pin formed of steel, a first reinforcement layer that is formed of a composite that includes reinforced fibers and a resin, having a cylindrical shape with a uniform thickness, and coupled to the interior surface of the cylindrical pin. A second reinforcement layer is formed of a composite that includes reinforced fibers having an elasticity that is less than the reinforced fibers of the first reinforcement layer. Further, a resin having a cylindrical shape with a uniform thickness is coupled to the interior surface of the first reinforcement layer.