Process for manufacturing a composite material part, the steering column support and lower cross bay realized using such a method

The present invention relates to a method of manufacturing a part made of composite material with organic matrix and fiber reinforcement, the method comprising the following steps: - draping automatically, flat or shaped, respectively, on a three-dimensional impression, at least one stratification (30, 31) having at least first and second dry wrinkles, different, at least partly superimposed so as to form a dry preform, respectively flat or three-dimensional, each fold being fibrous, folds differing from each other by the structure , positioning on the preform, the fibers constituting them, and / or geometry of the fold, - thermoforming the preform, thermoforming being performed when it was draped flat in step a) in a three-dimensional impression of a first mold to impart a three-dimensional shape, - impregnating within a mold the preform thus thermoformed by at least one polymer , The preform being displaced in case of flat layup in step a) of the first thermoforming mold to a second mold for impregnation.