Process for manufacturing pre-cured parts of composite material with green-applied stiffeners

A process for manufacturing a structural member from pre-cured elements composite material and green stiffeners, wherein at least two parts made of composite materials consisting of fibers and resin are structurally bonded, in which a first part, called a base part or support, is in a cured condition;

• and a second part, called a stiffener, is in a green condition and wherein the bonding of both parts is carried out by means of a structural adhesive sheet, so that the second part is compacted against the first part, with crosslinking of the resin of the composite material of the second part and adhered of the first part through the adhesive sheet said process comprising the following steps:
• a) laminating superimposed layers of composite material in a pre-impregnated condition, so that orientation of the fibers adapts to structural requirements of the to be obtained, producing from the resulting laminated layers the base part (1) on the one hand, and on the other hand, an assembly of basic stacks of laminated layers (7) destined to form the second part (2);
• b) curing the base part (1) obtained in step a);
• c) mounting the laminated layers (7) destined to form the second part (2) on a bench and introducing the bench and the laminated layers mounted thereon in a thermo-forming machine with a thermo-forming tool (8) and carrying out a hot forming cycle by applying heat and vacuum, to obtain halves of the second part (2) which halves are then bonded to each other to form the complete second part (2);
• d) removing the second part (2) from the thermo forming tool (8) and introducing said second part (2) in angle pieces (4,4′) previously fitted over a turning frame, said angle pieces being provided with a plurality of channels in which a plurality of elastomeric pipes (5,5′) are housed for retaining resin in the composite material of said second part (2), applying a structural adhesive sheet to the second part (2) in an area where said second part (2) is to be bonded to the base part (1), tightening the angle pieces (4, 4′) against the laminate layers of said second part (2) and placing a cradle with the already cured base part (1) beneath the turning frame, turning the turning frame so that said second part (2) is over the base part (1) and removing the turning frame and
• e) once the second part (2) has been positioned over the already cured base part (1), enclosing the assembly of said base part (1) and said second part (2) with said angle pieces (4, 4′) thereon inside a vacuum bag and sealing the latter by means of a mastic strip fitted around its perimeter;
• thereby assuring tightness to prevent resin of the composite material of the second part (2) from flowing outwardly from said second part;
• f) loading the enclosed assembly inside the vacuum bag in a chamber of an autoclave support tool, closing the latter hermetically, carrying out a curing cycle of the second part (2) under pressure and temperature and then allowing the autoclave chamber to reach pressure and room temperature conditions again, after which the assembly formed by the previously cured base part (1) and the second part (2), now cured, and adhered to said base part (1), is removed from the autoclave.