Method and apparatus for joining thermoplastic composite components

A method of blind welding thermoplastic composite components, comprising:

• providing a first thermoplastic composite (FTPC) component having a thickness that extends between an outer surface and an opposite FTPC bonding surface, the first thermoplastic composite component having a first melting temperature;
• providing a second thermoplastic composite (STPC) component having a STPC bonding surface, the second thermoplastic composite component having a second melting temperature;
• providing an interface layer comprising a thermoplastic material, the interface layer having a third melting temperature;
• disposing the interface layer between the FTPC bonding surface and the STPC bonding surface, such that the FTPC bonding surface is contiguous with the interface layer, and the STPC bonding surface is contiguous with the interface layer;
• disposing an external susceptor adjacent to the outer surface of the first thermoplastic composite component, wherein the external susceptor includes a central segment and a plurality of lateral segments contiguous with the central segment, wherein the central segment and the plurality of lateral segments are configured to respond differently to an application of an electromagnetic field;
• applying a normal force to the outer surface of the first thermoplastic composite component without an application of an opposing second normal force to the second thermoplastic component;
• and
• applying an electromagnetic field to the central segment and the plurality of lateral segments using an inductor, wherein the central segment and the plurality of lateral segments are configured such that the electromagnetic field heats the central segment to the first melting temperature or above, and heats the lateral segments to a temperature below the first melting temperature, and the electromagnetic field is applied until a region of the first thermoplastic composite component aligned with the central segment is at or above the first melting temperature, the interface layer is at or above the third melting temperature, and at least a portion of the second thermoplastic composite component is at or above the second melting temperature.