Abstract: A method for fabrication or production of composite structures, which has particular advantages when fabricating large structures, includes the steps of procuring a composite panel, such as carbon-fiber-reinforced resin. The edge of the composite panel its adhesively fixed in the slot of a bifurcated metallic piece. After the composite panel is adhesively fixed to the metallic piece, the metallic piece is stir-friction welded to another metal piece. The stir-friction welding occurs at a lower temperature than fusion welding, and so the adhesive bond between the metallic element and the composite panel is less affected. When two composite panels are each adhesively fastened to a metallic element, the two metallic elements can, in turn, be stir-friction welded. Thus, large panels can be fabricated.

Abstract: A method for fabrication or production of composite structures, which has particular advantages when fabricating large structures, includes the steps of procuring a composite panel, such as carbon-fiber-reinforced resin. The edge of the composite panel is adhesively fixed in the slot of a bifurcated metallic piece. After the composite panel is adhesively fixed to the metallic piece, the metallic piece is stir-friction welded to another metal piece. The stir-friction welding occurs at a lower temperature than fusion welding, and so the adhesive bond between the metallic element and the composite panel is less affected. When two composite panels are each adhesively fastened to a metallic element, the two metallic elements can, in turn, be stir-friction welded. Thus, large panels can be fabricated.

Abstract: A seam (16) between juxtaposed workpieces (14) is welded or heat-treated by friction-stir using a pin tool (12) driven by an apparatus (18) which controllably positions the pin tool (12) in the vertical direction (8). The workpiece (14) is supported by an anvil (22). The joint is heated by rotation of the pin tool (12) inserted into the joint from the obverse side. In order to provide a good weld through the thickness of the workpiece, a sensor (34, 310) senses electrical characteristics near the heated or welded region, and generates a control signal which tends to control the position of the pin tool near the reverse side of the weld. The sensor is located adjacent the weld (16s) on the obverse side, and is preferably protected by mounting in a depression (22c) in the anvil (22). In one embodiment, the sensor (34) senses magnetic characteristics near the weld. In another embodiment, the sensor (310) senses conduction, conductivity, or eddy currents in the vicinity of the weld.