Acoustic attenuation structure made of composite material and method for manufacturing same

Annular or semi-annular acoustic attenuation structure comprising an inner skin and an outer skin, defining between them an annular or semi-annular volume, and a plurality of partitions extending in a space in a radial direction perpendicular to the inner and outer skins and in a circumferential direction of the annular or semi-annular acoustic attenuation structure to define a plurality of adjacent chambers that extends along the circumferential direction, the inner and outer skins and the plurality of partitions being made of composite material comprising a fibrous reinforcement densified by a matrix, the fibrous reinforcement of the inner skin or the outer skin includes at least one fibrous layer extending over a length of the annular or semi-annular acoustic attenuation structure, wherein the fibrous reinforcement of each partition is formed with a first portion of one or several fibrous layers extending in the radial direction and in the circumferential direction, a second and remaining portion of said one or several fibrous layers of each partition extending in an axial direction from said first portion to substantially a first portion of another one or several fibrous layers of another partition that is adjacent said partition, wherein three adjacent partitions of the plurality of partitions extending in the radial direction and that define two adjacent chambers of the plurality of adjacent chambers are formed with, respectively, the first portions of three different ones of the one or several fibrous layers such that each partition of the three adjacent partitions is separately formed, wherein, for each partition, the second and remaining portion of said one or several fibrous layers extending in the axial direction is layered on said at least one fibrous layer of the fibrous reinforcement of only one of the inner skin and the outer skin,

• wherein the second and remaining portions of two adjacent partitions of the plurality of partitions extend in said axial direction without being woven to each other,
• wherein the first portions of said three different one or several fibrous layers extend in the radial direction without being woven to each other.