Method for producing a reinforced thermoplastic part, bumper beam, and bumper beam comprising such

Method for producing a thermoplastic part reinforced by a reinforcing sheet appearing on one of the faces of said part, characterized in that it consists in: - providing a mold comprising a main cavity which defines the general shape of the part and secondary cavities opening into a wall of the main cavity and defining excrescences (10, 11, 12) projecting from one of the faces of the part, - deposited in the mold a reinforcing sheet (8) consists of a woven or nonwoven reinforcing fibers mixed with thermoplastic material, against said wall of the main cavity, sealing the backing sheet and the mouth of the secondary cavities, - introducing a thermoplastic possibly filled with fibers into the main cavity of the mold, the side of the backing sheet opposite to the secondary cavities, in an amount sufficient to fill the cavity pri ncipale and the secondary cavities, - demoulding the piece .