Method for assembling a rotor blade of a wind turbine

A method for assembling a rotor blade of a wind turbine, the method comprising:

• a) providing at least two different rotor blade modules that segment the rotor blade along a longitudinal direction thereof, wherein each rotor blade module has a sloped interface section, and wherein the sloped interface sections comprise a weldable thermoplastic resin and/or a weldable thermoset resin;
• b) providing a resistive element;
• c) arranging the at least two different rotor blade modules and the resistive element in such a way that the sloped interface sections face each other and the resistive element is sandwiched between the sloped interface sections;
• d) energizing the resistive element to apply heat to the weldable thermoplastic resin and/or the weldable thermoset resin to melt or to soften the weldable thermoplastic resin and/or the weldable thermoset resin;
• and
• e) joining the sloped interface sections together at a joint by means of the molten or softened weldable thermoplastic resin and/or the weldable thermoset resin to form the rotor blade;
• wherein a transversal stiffener that runs perpendicular to the longitudinal direction is provided for supporting the sloped interface sections from an inner space of the rotor blade.