Pressure sensitive flow distribution medium for VARTM

1. A method for manufacturing a fibre reinforced composite by means of vacuum assisted resin transfer moulding, comprising:

placing a fibre material in a mould;

placing a flow distribution medium onto the fibre material, the flow distribution medium including a vacuum foil integrated with the flow distribution medium such that an upper surface of the flow distribution medium forms the vacuum foil, the vacuum foil forming a closed mould cavity; and

applying a vacuum to the closed mould cavity, wherein a resin is propagated through the fibre material due to the vacuum applied to the closed mould cavity;

wherein the flow distribution medium has a thickness depending on a pressure gradient over the vacuum foil;

wherein a first portion of the flow distribution medium in front of a resin flow front has a reduced thickness in a compressed state compared to the thickness of a second portion of the flow distribution medium behind the resin flow front which is in a non-compressed state, the second portion of the flow distribution medium lifting the vacuum foil to allow the resin to flow faster in a direction of the resin flow front;

wherein the flow distribution medium comprises a pultruded hollow membrane with a top layer and a bottom layer and with multiple thin walls connecting the top layer and the bottom layer with each other.

2. The method as claimed in claim 1 , wherein the flow distribution medium has a stiffness that enables the flow distribution medium to lift the vacuum foil.

3. The method as claimed in claim 1 , wherein the flow distribution medium comprises thermoplastic material.

4. The method as claimed in claim 1 , wherein the flow distribution medium comprises polyester and/or polypropylene and/or polyamide.

5. The method as claimed in claim 1 , wherein the flow distribution medium comprises material having a thickness between 2 mm and 10 mm at 1000 mbar and/or between 0.1 and 0.5 mm at 50 mbar.

6. The method as claimed in claim 1 , wherein the flow distribution medium comprises material having a load bearing capacity between 0.3 kg/cm 2 and 0.7 kg/cm 2 .

7. The method as claimed in claim 1 , further comprising:

maximizing the vacuum inside the closed mould cavity when a resin injection is finalized for reducing the thickness of the flow distribution medium.

8. The method as claimed in claim 1 , wherein the fibre reinforced composite is a component of a wind turbine.

9. A method for manufacturing a fibre reinforced composite by means of vacuum assisted resin transfer moulding, comprising:

placing a fibre material in a mould;

placing a flow distribution medium onto the fibre material; and

covering the fibre material and the flow distribution medium with a vacuum foil for forming a closed mould cavity between the mould and the vacuum foil; and

applying a vacuum to the closed mould cavity, wherein a resin is propagated through the fibre material due to the vacuum applied to the closed mould cavity;

wherein the flow distribution medium has a thickness depending on a pressure gradient over the vacuum foil;

wherein the flow distribution medium comprises a pultruded hollow membrane with a top layer and a bottom layer and with multiple thin walls connecting the top layer and the bottom layer with each other.

10. The method as claimed in claim 9 , wherein the fibre reinforced composite is a component of a wind turbine.

11. A method for manufacturing a fibre reinforced composite by means of vacuum assisted resin transfer moulding, comprising:

placing a fibre material in a mould;

placing a flow distribution medium onto the fibre material; and

covering the fibre material and the flow distribution medium with a vacuum foil for forming a closed mould cavity between the mould and the vacuum foil, the vacuum foil laid directly onto the flow distribution medium; and

applying a vacuum to the closed mould cavity, wherein a resin is propagated through the fibre material due to the vacuum applied to the closed mould cavity;

wherein the flow distribution medium has a thickness depending on a pressure gradient over the vacuum foil;

wherein a first portion of the flow distribution medium in front of a resin flow front has a reduced thickness in a compressed state compared to the thickness of a second portion of the flow distribution medium behind the resin flow front which is in a non-compressed state, the second portion of the flow distribution medium lifting the vacuum foil to allow the resin to flow faster in a direction of the resin flow front;

wherein the flow distribution medium includes a top layer and a bottom layer, the bottom layer being a constant flow resistance layer, and the top layer being a pressure sensitive layer.

12. The method as claimed in claim 11 , further comprising:

placing a peel ply between the flow distribution medium and the fibre material.

13. The method as claimed in claim 11 , wherein the flow distribution medium comprises nonwoven fibre material.

14. The method as claimed in claim 11 , wherein the flow distribution medium comprises fibres, the fibres having a diameter of at least 10 μm and/or maximal 500 μm.

15. The method as claimed in claim 11 , wherein the flow distribution medium comprises fibres, the fibres bonded at each other.

16. The method as claimed in claim 11 , wherein the fibre reinforced composite is a component of a wind turbine.