Composite material structure for railroad car chassis

Abstract

A structure, made from composite materials for a vehicle chassis, being configured to receive an undercarriage at its ends and includes at least one central beam that includes a median box having a central part and two ends with a reinforced structure, and the central part includes a reinforced part increasing the strength of the beam with respect to the bending stresses imposed by the transported load. The median box is reinforced by two lateral boxes extending over the entire length of the median box), assembled to the median box, the upper faces of which, together with the upper face of the median box, form the upper face of the beam. The structure includes a floor that covers the upper faces of the median box and the lateral boxes. The elements making up the structure have shapes that are simple, easy to make from composite materials and easy to assemble.

What is claimed is: 
     
         1 . A composite material structure, for chassis of vehicles for transporting freight, or passengers, said structure being configured to accept running gear at each of its ends, the structure includes at least one central beam forming a platform on which the load of the vehicle rests, said beam including:
 a middle box having a central portion and two ends, said ends having reinforcements for withstanding the stresses transmitted to the chassis by the articulation elements of the running gear and by the shock absorber elements disposed at the ends of the vehicle, the central portion of the middle box being configured so as to have a reinforced portion increasing the resistance of the beam to bending forces imposed by the transported load;   two lateral boxes extending over all the length of the middle box, assembled to said middle box, the upper faces of which form with the upper face of the middle box the upper face of the beam, said lateral boxes being configured so as to reinforce the resistance of the beam to longitudinal and transverse bending forces imposed on it;   a covering floor forming a skin, configured so as to cover the upper faces of the middle box and the lateral boxes;   
       The various elements constituting the beam being made of composite materials reinforced with glass fibers or carbon fibers or a mixture of glass fibers and carbon fibers. 
     
     
         2 . The structure as claimed in  claim 1 , wherein the middle box consists of an upper half-box extending over all the length of the beam and a lower half-box disposed in the central portion, the two half-boxes each including a bottom and two lateral walls, the upper half-box and the lower half-box being arranged relative to each other so that the bottom of the upper half-box forms the upper face of the middle box and the bottom of the lower half-box forms the lower face of said box, the bottom of the lower half-box extending externally thereof toward the ends of the beam. 
     
     
         3 . The structure as claimed in  claim 2 , wherein a composite material intermediate partition is placed between the upper half-box and the lower half-box so as to reinforce the stiffness of the middle box and the resistance to buckling of the lateral walls of the upper half-box and of the lateral walls of the lower half-box. 
     
     
         4 . The structure as claimed in  claim 1 , wherein the covering floor consists of a principal element in the form of a monolithic composite material plate reinforced with glass fibers including in its middle portion a composite material reinforcing element sized so as to cover the upper face of the middle box. 
     
     
         5 . The structure as claimed in  claim 1 , wherein the bottom of the upper half-box, the bottom of the lower half-box and a middle reinforcing element of the principal element of the skin disposed on the upper face of the structure are made of monolithic composite material reinforced primarily with unidirectional fibers, said fibers preferably being carbon fibers. 
     
     
         6 . The structure as claimed in  claim 1 , further includes composite material lateral reinforcements disposed on either side of the beam and adapted to absorb forces applied to the lateral portions of the structure by the transported load, each reinforcement being fastened to a lateral box by one of its ends and to the middle box by its other end. 
     
     
         7 . The structure as claimed in  claim 1 , wherein the elements forming the beam consist of composite material plane faces. 
     
     
         8 . The structure as claimed in  claim 2 , wherein the upper half-box includes a plane bottom consisting of a monolithic composite material plate and two lateral walls with a sandwich structure consisting of two composite material thin skins reinforced with glass fibers and a core consisting of an element formed of polymer material foam or a honeycomb structure material or a balsa type wood. 
     
     
         9 . The structure as claimed in  claim 2 , wherein the lower half-box includes a bottom consisting of a monolithic composite material plate and lateral walls with a sandwich structure consisting of two composite material thin skins reinforced with glass. fibers and a core consisting of an element made of polymer material foam or a honeycomb structure material or a balsa type wood. 
     
     
         10 . The structure as claimed in  claim 6 , wherein the lateral reinforcing elements have a sandwich structure consisting of two composite material thin skins reinforced with glass fibers and a core consisting of an element made of polymer material foam or a honeycomb structure material or a balsa type wood. 
     
     
         11 . The structure as claimed in  claim 1 , wherein the various elements of said structure include rims adapted to enable the assembly of said elements by gluing and/or bolting and/or riveting, two elements assembled to each other having rims adapted to be placed face-to-face at the time of assembly.