Abstract: The preform made of a 3D fibrous structure comprises at least 3 layers (1, 2) of weft yarns and/or warp yarns, the structure being woven as a single part by multilayer weaving between a plurality of layers of warp yarns and a plurality of layers of weft yarns. It comprises a predetermined distribution of points of intersection of warp yarn and weft yarn that are bonded by polymer. The polymer represents a mass of less than or equal to 10%. The preform comprises at least one thermoformed portion in which the warp yarns and the weft yarns are bonded at the intersections thereof by polymer where at least one of the warp and/or weft yarns bears polymer.

Abstract: The preform made of a 3D fibrous structure comprises at least 3 layers (1, 2) of weft yarns and/or warp yarns, the structure being woven as a single part by multilayer weaving between a plurality of layers of warp yarns and a plurality of layers of weft yarns. It comprises a predetermined distribution of points of intersection of warp yarn and weft yarn that are bonded by polymer. The polymer represents a mass of less than or equal to 10%. The preform comprises at least one thermoformed portion in which the warp yarns and the weft yarns are bonded at the intersections thereof by polymer where at least one of the warp and/or weft yarns bears polymer.