A system for coupling reinforced thermosetting resin pipes includes a first pipe having a tapered, spigot end, wherein a portion of an external surface of the tapered, spigot end of the first pipe is bonded to a first thermoplastic material and a second pipe having a tapered, socket end adapted to internally receive the tapered, spigot end of the first pipe, wherein a portion of an internal surface of the tapered, socket end of the second pipe is bonded to a second thermoplastic material. A method of coupling the first pipe and the second pipe includes inserting the first pipe into the second pipe; coupling the first pipe to the second pipe via a mechanical joint; and employing a thermal joining process to bond the first thermoplastic material to the second thermoplastic material by heating the first and second thermoplastic materials to melt the first and second thermoplastic materials.

Composite joints and methods of forming composite joints are presented. A composite joint comprising: a first composite component formed of one of a thermoset material or a first thermoplastic material; a second composite component formed of a thermoset material or a third thermoplastic material; a thermoplastic joining film formed of a second thermoplastic material between the first composite component and the second composite component, the second thermoplastic material different from the thermoset material, first thermoplastic material, and third thermoplastic material; and a carbon conductive layer in the thermoplastic joining film.

A composite fibrous susceptor for use in induction welding is described, along with methods of its construction and use. The composite fibrous susceptor can include a magnetically susceptible continuous fiber in conjunction with a thermoplastic polymer. The composite fibrous susceptor can be deposited according to an additive manufacturing process on a surface to be bonded according to an induction welding process.

A composite fibrous susceptor for use in induction welding is described, along with methods of its construction and use. The composite fibrous susceptor can include a magnetically susceptible continuous fiber in conjunction with a thermoplastic polymer. The composite fibrous susceptor can be deposited according to an additive manufacturing process on a surface to be bonded according to an induction welding process.

A composite structure and methods of forming composite structures are provided. A composite structure comprises a first composite part; a second composite part welded to the first composite part at a joint; and the joint between the first composite part and the second composite part comprising doped fibers.