Fiber structure woven as a single piece by 3d weaving and application to the manufacturing of composite material part

A fiber structure woven as a single piece by three-dimensional weaving, the fiber structure having opposite surfaces and comprising:

• a first portion including a plurality of layers of warp yarns and forming a first portion of a thickness of the fiber structure between its opposite surfaces;
• a second portion including a plurality of layers of warp yarns and forming a second portion of the thickness of the fiber structure, the warp yarns being arranged in columns each of which includes warp yarns of the first portion and of the second portion;
• and
• in each plane of the fiber structure, a set of weft yarns interlinking the layers of warp yarns of the first portion and of the second portion while leaving at least one non-interlinked zone separating the first and second portions over a portion of a dimension of the fiber structure in the weft direction from an edge of the fiber structure to an end of non-interlinked zone, wherein:
• one or more same first weft yarns interlink layers of warp yarns of the first portion of the fiber structure adjacent to the non-interlinked zone and layers of warp yarns of the second portion of the fiber structure beyond the non-interlinked zone;
• and
• one or more same second warp yarns interlink layers of weft yarns of the second portion of the fiber structure adjacent to the non-interlinked zone and layers of warp yarns of the first portion of the fiber structure beyond the non-interlinked zone;
• wherein paths of the first weft yarns and of the second weft yarns cross over in at least one transition zone extending in the fiber structure from the end of the non-interlinked zone;
• and
• the transition zone extends in the weft direction over a distance that is greater than a pitch between adjacent warp columns.

A fiber structure woven as a single piece by three-dimensional weaving, the fiber structure having opposite surfaces and comprising:

• a first portion including a plurality of layers of weft yarns and forming a first portion of the thickness of the fiber structure between its opposite surfaces;
• a second portion including a plurality of layers of weft yarns and forming a second portion of thickness of the fiber structure, the weft yarns being arranged in columns each of which includes weft yarns of the first portion and of the second portion;
• and
• a set of warp yarns interlinking the layers of weft yarns of the first portion and of the second portion while leaving at least one non-interlinked zone separating the first and second portions over a portion of a dimension of the fiber structure in the warp direction from an edge of the fiber structure to an end of non-interlinked zone, wherein:
• one or more same first warp yarns interlink layers of weft yarns of the first portion of the fiber structure adjacent to the non-interlinked zone and layers of weft yarns of the second portion of the fiber structure beyond the non-interlinked zone;
• and
• one or more same second weft yarns interlink layers of warp yarns of the second portion of the fiber structure adjacent to the non-interlinked zone and layers of weft yarns of the first portion of the fiber structure beyond the non-interlinked zone;
• wherein the paths of the first warp yarn and of the second warp yarn cross over in at least one transition zone extending in the fiber structure from the end of the non-interlinked zone;
• and
• the transition zone extends in the warp direction over a distance that is greater than a pitch between adjacent weft columns.