FIBROUS PREFORM HAVING A Pi-SHAPED CROSS-SECTION, IN PARTICULAR FOR A COMPOSITE MATERIAL BLOWER PLATFORM
The invention relates to a fibrous preform (10) having a pi-shaped cross-section that has a base (12), comprising a first and second surface opposite each other and legs (14, 16) extending from the second surface. The preform includes a fiber structure woven into a single part by means of three-dimensional weaving using a plurality of warp (or woof) thread layers interconnected by woof (or warp) threads from a plurality of woof (or warp) thread layers. In each plane of the fibrous preform, woof (warp) threads of a first woof (warp) thread group (t1-t6) continuously extend through the base (12) between two opposite edges of the latter, and woof (warp) threads from a second woof (warp) thread group (t7-t9) continuously extend from an end of one leg (14) to an end of the other leg (16) while passing into the base, a mutual, dual intersection (18a, 18b) occurring between the threads of the first group and the threads of the second group.