Bumper beam with twin shells and a stiffening element

The hull (1) has housing to receive reinforcement (19) in its interior. The reinforcement is a metal reinforcement made out of aluminum or a reinforcement of composite material incorporating a metal. The housing is formed by an open section and a closing unit is designed to close the open section. The closing unit forms a lining of the hull to fit with the hull by forming a lengthened hollow body. An Independent claim is also included for a beam of a motor vehicle.