Pressure sensitive flow distribution medium for VARTM
A method for manufacturing a fibre reinforced composite by means of a vacuum assisted resin transfer moulding, comprising the steps of placing a fibre material in a mould, placing a flow distribution medium onto the fibre material, and covering the fibre material ( 1 ) and the flow distribution medium with a vacuum foil for forming a closed mould cavity between the mould and the vacuum foil is described. It is characterised in using a flow distribution medium with a thickness depending on a pressure gradient over the vacuum foil.
1. A method comprising:
applying a vacuum to a closed mould cavity to cause a flow of resin to propagate through a fibre material of the closed mould cavity, and, as the resin infuses the fibre material, a drop in the vacuum occurs resulting in an increase of a thickness of a flow distribution medium above infused fibre material and behind a resin flow front, wherein the increase in the thickness of the flow distribution medium proximate the resin flow front lifts a vacuum foil covering the flow distribution medium ahead of the resin flow front so that the resin propagates through the fibre material with less resistance;
wherein an additional flow distribution medium that is a different material than the flow distribution material is disposed directly below the flow distribution material, the additional flow distribution medium being coextensive with the flow distribution medium across the closed mould cavity;
wherein the vacuum foil is laid directly on top of the flow distribution medium, and a peel ply is disposed between the additional flow distribution medium and the fibre material.
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 nonwoven fibre material.
4. The method as claimed in claim 1 , wherein the flow distribution medium comprises fibres, the fibres having a diameter of at least 10 μm and/or maximal 500 μm.
5. The method as claimed in claim 1 , wherein the flow distribution medium comprises thermoplastic material.
6. The method as claimed in claim 1 , wherein the flow distribution medium comprises polyester and/or polypropylene and/or polyamide.
7. The method as claimed in claim 1 , wherein the flow distribution medium comprises material having a thickness between 2 mm and 10 mm at 1.000 mbar and/or between 0.1 and 0.5 mm at 50 mbar.
8. 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 .
9. The method as claimed in claim 1 , wherein the flow distribution medium comprises fibres, the fibres bonded at each other.
10. 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.