A method of connecting surfaces of first and second molded parts by electromagnetic welding. The first molded part includes a first lightning strike protection (LSP) material at an outer surface thereof. The method includes providing the first and second molded parts to comprise a heat meltable coupling and an induction-sensitive component; bringing together the surfaces to be connected and pressurizing the surfaces by providing a pressurizing body against the molded parts; generating an electromagnetic field in the surfaces to be connected of the molded parts by means of an inductor, thereby heat melting the coupling means by heating the induction-sensitive component; cooling the outer surface of the first molded part by providing a heat sink in contact with the outer surface; and coupling the molded parts under pressure by the molten heat meltable coupling means. A second lightning strike protection (LSP) material is provided at the surfaces to be connected.

The invention relates to the use of a low Tg compatible resin as an adhesive layer for the welding of a thermoplastic composite structure to a thermoplastic or thermoset structure. The invention is especially good for the welding of large parts, such as wind turbine halves and spar caps. A useful thermoplastic composite is one formed by the infusion and curing of long fibers by a reactive acrylic liquid resin system, such as ELIUM resin systems from Arkema.

Described herein are thermoplastic composites and methods of making thereof. The thermoplastic composites disclosed herein can include at least one randomly-oriented carbon fiber layer in the laminate to improve induction heating efficiency of the thermoplastic composite.

The device for welding thermoplastic parts includes a matrix for positioning the parts to be assembled, the matrix including an amagnetic insulating insert that defines joining zones in which the welds must be produced, a bladder defining a sealed volume and means for producing a partial vacuum in the sealed volume, and means for moving a magnetic induction head to near the joining zones and without making contact with the bladder. The welding process includes positioning at least one first part, then of placing metal inserts on areas of the first part corresponding to the joining zones that must be welded, and then positioning at least one second part. A bladder is put in place covering the parts and a partial vacuum is created in the volume defined by the bladder. The magnetic induction head is moved to produce the weld bead without contact while the partial vacuum is maintained.

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.

A method for producing a rotor blade of a wind turbine includes the following steps: a) providing at least two different components of the rotor blade, b) placing a resistive element between the components, c) placing a thermoplastic or weldable thermoset resin between the components, d) energizing the resistive element so that the resistive element applies heat to the thermoplastic or weldable thermoset resin to melt or to soften it, and e) joining the components together by means of the molten or softened thermoplastic or weldable thermoset resin.