Reinforcement material for composite laminate
A woven fabric prepreg for constructing a composite laminate comprises two sheets of fabric woven from tows of fibres, impregnated with a polymer matrix and adhered together. Each sheet is woven in a satin weave such that the tows create long floats on at least one side of the sheet. The sheets are positioned face-to-face with the long floats parallel, such that the tows pack together and the space between the sheets is minimised.
1 . A method of manufacturing a woven multi-layer fabric prepreg for use in constructing a composite laminate, comprising the steps of:
providing two sheets of woven fabric having tows of fibres in a satin weave, such that said tows create long floats on each side of each sheet, each sheet being elongate and having a longitudinal direction;
impregnating each sheet of fabric with a polymer matrix, wherein only a face of one of said sheets is impregnated with the polymer matrix and only a back of the other of said sheets is impregnated with the polymer matrix, the face having long floats aligned with the longitudinal direction and the back having long floats aligned in a direction orthogonal to the longitudinal direction;
placing the sheets together in any one of:
face-to-face, so that there is only a single layer of polymer matrix between the faces, and
back-to-back, so that there is only a single layer of polymer matrix between the backs,
with the long floats parallel, such that the tows pack together and enclosed free space between the sheets is minimised, and so that the longitudinal directions are aligned; and
adhering said sheets together to form the woven multi-layer fabric prepreg.
2 . The method of manufacturing a woven multi-layer fabric prepreg as claimed in claim 1 , further comprising cutting the woven multi-layer fabric prepreg into pieces.
3 . The method of manufacturing a woven multi-layer fabric prepreg as claimed in claim 2 , wherein the woven multi-layer fabric prepreg is elongate and said cutting occurs in a direction transverse to a longitudinal direction of the woven multi-layer fabric prepreg.
4 . The method of manufacturing a woven multi-layer fabric prepreg as claimed in claim 1 , wherein at least one of the two sheets of fabric is provided on a roll.
5 . The method of manufacturing a woven multi-layer fabric prepreg as claimed in claim 1 , wherein at least one of the two sheets of fabric is greater than 100 m long.
6 . The method of manufacturing a woven multi-layer fabric prepreg as claimed in claim 1 , wherein each sheet has a fabric weight of over 500 gsm so that the woven multi-layer fabric prepreg has a fabric weight of over 1000 gsm.
7 . The method of manufacturing a woven multi-layer fabric prepreg as claimed in claim 1 , wherein each sheet has a fabric weight of between 500 gsm and 525 gsm so that the woven multi-layer fabric prepreg has a fabric weight of between 1000 and 1050 gsm.
8 . The method of manufacturing a woven multi-layer fabric prepreg as claimed in claim 1 , wherein the satin weave is any one of a four, five, and eight harness satin weave.
9 . A method of manufacturing a composite laminate, comprising the steps of:
obtaining a pattern or a mould;
obtaining a first woven multi-layer fabric prepreg manufactured using the method of claim 1 ;
creating a laminate by placing a plurality of layers of said first fabric prepreg onto said pattern or into said mould; and
curing said laminate using heat.
10 . The method of manufacturing a composite laminate according to claim 9 , further comprising the step of:
obtaining a second woven fabric prepreg, said second fabric prepreg having a lower fabric weight than said first fabric prepreg;
and wherein said step of creating a laminate further comprises the step of placing a layer of said second fabric prepreg before said layers of said first fabric prepreg.
11 . The method of manufacturing a composite laminate according to claim 10 , wherein a single debulking occurs after placement of the second fabric prepreg and one layer of the first fabric prepreg.
12 . The method of manufacturing a composite laminate according to claim 10 , further comprising the step of placing a further layer of said second fabric prepreg after said layers of said first fabric prepreg.
13 . The method of manufacturing a composite laminate according to claim 9 wherein there are an odd number of layers of the first fabric prepreg.
14 . The method of manufacturing a composite laminate according to claim 13 wherein there are five layers of the first fabric prepreg.
15 . The method of manufacturing a composite laminate according to claim 9 , wherein said layers of said first fabric prepreg are placed such that the tows of adjacent layers are neither parallel nor orthogonal to each other.