Abstract: A method of forming composite sine wave spars from composite material. In accordance with the method, the sine wave spar is formed of web plies, filler plies, separator plies and cap plies. The edges of the web plies are cut to form a plurality of teeth having different geometric configurations. The web plies are first formed to the sine wave contours of a tool having the desired final part geometry. The teeth of the web plies are then folded over the edges of the tool to form a portion of the flanges of upper and lower U-shaped channels. The portions of the flanges of the U-shaped channels not covered by the teeth are formed using filler plies that intermesh with the teeth to form a layer of the flanges of the respective upper or lower U-shaped channel. The flanges are reinforced through the use of separator plies that are placed between the filler plies. The formed upper and lower U-shaped channels are joined together so that their respective flanges are located in line with each other.

Abstract: Rib and spar webs are joined in a composite wingbox to eliminate fasteners by welding the webs along bond lines defined by overlapping sections of the webs. Heat to produce the weld is generally achieved resistively by connecting a multistrip susceptor positioned along the bond line to a current source, since the geometry makes it difficult to heat these web joints inductively. The wingbox is completed without fasteners by welding skins to the rib-spar wingbox.

Abstract: A method of forming composite sine wave spars from composite material. In accordance with the method, the sine wave spar is formed of web plies, filler plies, separator plies and cap plies. The edges of the web plies are cut to form a plurality of teeth having different geometric configurations. The web plies are first formed to the sine wave contours of a tool having the desired final part geometry. The teeth of the web plies are then folded over the edges of the tool to form a portion of the flanges of upper and lower U-shaped channels. The portions of the flanges of the U-shaped channels not covered by the teeth are formed using filler plies that intermesh with the teeth to form a layer of the flanges of the respective upper or lower U-shaped channel. The flanges are reinforced through the use of separator plies that are placed between the filler plies. The formed upper and lower U-shaped channels are joined together so that their respective flanges are located in line with each other.

Abstract: A method for fabricating composite parts having improved pulloff strengths between portions of the composite part. In one embodiment, a sine wave spar is formed from two U-shaped channels having opposing flanges and a central web. The U-shaped channels are joined along the webs. The triangular gaps between the edges of the joined U-shaped channels are filled using a titanium radius filler that is configured to fit within the gaps. After the titanium radius filler is placed within the gaps, additional layers of composite material are placed over the titanium radius filler and the flanges of the U-shaped channels to form the caps of the I-beam. The resulting composite workpiece is then placed within appropriate tooling and cured within an autoclave. In other embodiments, the method of the invention is used to form spars, ribs, stringers, or bulkheads from composite materials.

Abstract: The processing time and energy efficiency of metal or composite bonding operations is improved by heating the lay-up preform of the structure in an induction heating press where energy goes primarily to heating the workpieces rather than to heating the tooling or being lost to the environment. The bonding process is especially beneficial for joining thermoplastic composites, but it also can be used with metals or thermosets. Preferential heating at the bondline is achieved by using shims to define the bondline and to define bead regions that have relief from contact with the susceptor envelope because of the thickness of the shims in the bondline regions.

Abstract: An apparatus for curing composite materials that emit large volumes of volatiles during processing. The apparatus includes tooling having a rigid forming surface contoured to the shape of the formed composite part. A plurality of passages extend from the forming surface through the tooling. The passages are in fluid contact with an exhaust port. A composite workpiece is laid up and placed adjacent the forming surface. The apparatus includes a heater that heats the composite workpiece to temperatures at which volatiles are emitted. An evacuation system draws the volatiles away from the composite workpiece through the passages in the tooling and out of the exhaust port. One embodiment of tooling according to the invention is used to form a sine wave spar. The tooling includes upper and lower tool inserts upon which U-shaped composite channels are formed. The upper and lower tools are placed adjacent to each other to form the web of the spar. Cap strips are placed on either side of the joined U-shaped channels.

Abstract: A method for fabricating composite parts having improved pull-off strengths between portions of the composite part. In one embodiment, a sine wave spar is formed from two U-shaped channels having opposing flanges and a central web. The U-shaped channels are joined along the webs. The triangular gap created between the edges of the two U-shaped channels along the joining surface are filled by interleaving layers of unidirectional prepreg with the layers of prepreg that form the caps or flanges of the sine wave spar. In one embodiment of the invention, the layers of prepreg used as radius filler plies become progressively narrower as they are interleaved from within the gap outward towards the outer edge of the flanges. In another embodiment, the layers of prepreg used as radius filler plies become progressively narrower as they are interleaved between the cap plies.

Abstract: A novel method and apparatus are provided for consolidating and perforating multilayer laminates by a combination of vibratory motion and impacting pressure applied by a special compacting tool preparatory to final cure.

Abstract: The present invention relates to a seaming apparatus a method for producing a continuous sheet of thermoplastic material having a predetermined width from a plurality of elongated thermoplastic tapes each having edges defining a transverse width less than the predetermined width and each tape being wound on a roll. The seaming apparatus comprising a frame having a seaming zone. A feed device is mounted on the frame for rotatably supporting a plurality of rolls in a predetermined relationship. An alignment mechanism is mounted on the frame for receiving the tapes from rolls thereof supported by the feed device and for guiding the tapes into the seaming zones along paths defining a predetermined transversely adjacent relationship when the edges of the tapes position adjacent one another form a contiguous area. Thermal heating elements are provided in the seaming zone for thermally joining the contiguous area of the tapes to form the contiguous sheet of thermoplastic material.

Abstract: Apparatus for forming elongate laminate into a predetermined configuration having a substantially uniform cross-sectional shape in the axial direction, including a plurality of roller pairs having complementary transverse peripheral profiles, plate members disposed between the roller pairs and the laminate and having a transverse configuration corresponding to the peripheral profiles of the rollers.