Before forming and analysing the formed FRP, the initial state of the layers and fibres must be investigated. For
this purpose, 2.5 mm thick FRP plates were embedded in an epoxy resin and micrographic pictures were
taken. The images are shown in Fig. 4. The dark grey areas of the samples represent the thermoplastic PA6, while
the glass fibres are shown in white. The unidirectional configuration of the FRP plates can be seen clearly in these
images again. Especially axially to the fibre direction, the individual fibre layers are clearly visible. In the
manufacturing process of the FRP blanks PA6 films and glass fibre sheets were stacked and bonded under pressure
and heat. By this, the heated thermoplastic penetrates the fibre layers. The layers generated within this
process cannot be annulled completely. In the lower image in Fig. 4 a photograph perpendicular to the fibre
direction is shown. Due to minimal variations of the photographing plane to the fibre direction, the fibres appear as
lines as the section is at a shallow angle to the viewing photographing plane.