Patent ID: 7503149

Claim:
A process for producing a thermostructural fiber/matrix composite monolith comprising two skins of composite material that are spaced apart and connected to each other by a plurality of filiform spacers of composite material, said process comprising the steps of: forming a flexible sandwich structure, comprising an intermediate flexible core, made of a material capable of being penetrated by a needle and impermeable to a resin that generates said matrix, and two external flexible fibrous reinforcements, placed on opposed external faces of said flexible core respectively; assembling said fibrous reinforcements and said core of said sandwich structure by stitching with a roving comprising a plurality of filaments that are not linked together to form stitches that include roving portions passing transversely through said fibrous reinforcements and said core, and said roving portions passing transversely through said fibrous reinforcements and said core forming, in the latter, after stitching, longitudinal channels that are provided between said filaments and extend from one of said fibrous reinforcements to the other; embedding said sandwich structure with said resin in a viscous state so that said resin penetrates said longitudinal channels of said transverse roving portions in order to form, at the position of each of them, a resin bridge in contact via its opposed ends with the resin that impregnates said flexible fibrous reinforcements; curing said resin embedding said sandwich structure; and removing said core.