Forming duct structure with overbraided woven fiber sleeve

A method for manufacturing, comprising:

• disposing a woven fiber sleeve over a mandrel to provide an overbraided mandrel, the woven fiber sleeve including a base section and a mount section, the base section wrapped circumferentially around the mandrel and extending longitudinally along the mandrel between a first end and a second end, the mount section disposed longitudinally at an intermediate location between the first end and the second end, and the mount section projecting out from the base section;
• arranging the overbraided mandrel with tooling, wherein the tooling includes an annular insert, the annular insert circumscribes a first portion of the mount section, and the annular insert is disposed between a second portion of the mount section and the base section;
• disposing a polymer material with the woven fiber sleeve to provide a duct structure, the duct structure including a tubular duct and an annular flange, the tubular duct formed by the base section, and the annular flange formed by the mount section;
• and
• removing the tooling including the annular insert to liberate the duct structure;
• wherein the annular insert has a cross-sectional geometry that tapers as the annular insert extends towards the first portion of the mount section.