METHOD FOR PRODUCING CONSTRUCTION ELEMENTS OF FIBRE-REINFORCED PLASTIC MATERIALS
A method for the production of a textile semifinished product consisting of a fibre nonwoven fabric for use as a preform for the production of components composed of fibre-reinforced plastic, in which the fibres are converted by laying/assembling/draping into a fibre nonwoven fabric in the shape of a band corresponding to the power absorptions of the respective component to be generated, being provided with required UD fibre portions and/or thermoplastic fibres and furthermore the fibre architecture of the band is permanently fixed by pre-defined seams.
1 . A method for producing components of fibre-reinforced plastics, such as control elements for the rotor blades as well as rotor blades of a helicopter, in which the fibres are positioned as fabric layers on a core and are hardened into a component by means of resin injection, having the following method steps:
the fibres are converted, by means of laying/assembling/draping, into a fibre nonwoven fabric in the shape of a band corresponding to the contours of the respective component to be generated,
required UD fibres are precisely positioned on the band and applied in the circumferential direction of the respective component to be generated,
the fibres of the fibre nonwoven fabric created in such a manner are fixed in their location by means of pre-defined seams and are thereby converted into a textile semifinished product that can be stored,
the band undergoes final contouring corresponding to the dimensions of the component to be produced subsequent to which said band is wound on a core of an injection tool and is solidified into the final preform by means of resin injection.
2 . The method as specified in claim 1 , characterised in that thermoplastic fibres can be added to the fibre nonwoven fabric in the shape of a band for the purposes of mechanically fusing the band on the core of the injection tool.
3 . The method as specified in claim 1 , characterised in that the thermoplastic fibres are added in the region of the high degree of drapability of the fibre nonwoven fabric exhibiting the shape of a band.
4 . The method as specified in claim 1 , characterised in that the required UD fibre portions are applied and fused in the neutral phase of the fibre nonwoven fabric exhibiting the shape of a band.
5 . The method as specified in claim 4 , characterised in that the required UD fibre portions are applied outside the regions having a high degree of drapability of the fibre nonwoven fabric exhibiting the shape of a band.
6 . The method as specified in claim 1 , characterised in that subsequent to the final contouring of the fibre nonwoven fabric exhibiting the shape of a band, it is provided with slits for integrating the components for the transmission of force into the preform.
7 . The method as specified in claim 2 , characterised in that upon mechanical fusing, the thermoplastic fibres of the fibre nonwoven fabric exhibiting the shape of a band are heated by means of a fusing roll.
8 . The method as specified in claim 1 , characterised in that a sewing unit generating a two-thread lock stitch is used to produce seams fixing the fibre architecture of the band.