  Flax fibre reinforced composites are becoming popular in the automotive and
civil industries due to their environmentally friendly nature in terms of
production and recycling and for their good specific strength. Textile
structures undergo transverse compaction during composite manufacturing which
changes the fabric thickness and ultimately fibre volume fraction of
composites. Here, different flax fibre structures were investigated for
compaction behaviour during composite forming to study the thickness changes of
these fabrics under pressures between 1 and 10 bars. A range of composite
manufacturing processes including vacuum infusion, autoclave curing and resin
transfer moulding were utilised. These fabrics were studied in single and multi
layer states, in dry and wet states, under different loading cycles and in
different orientations of the fabric plies (00/00 and 00/900). Nesting of the
layers has been calculated for single plies and for multi-layer stacks of dry
fabrics. It was observed that under transverse compression, the structure of
the preform plays a vital role in determining the thickness of the preform. The
compressibility pattern of these various structures was also dissimilar for
single layer and multi-layer stack which was attributed to the different
nesting behaviours of these flax fibre structures.
