Pressure sensitive flow distribution medium for VARTM

Patent metadata

Field	Value
Publication number	US-9815245-B2
Application number	US-201414171946-A
Country	US
Kind code	B2
Filing date	Feb 4, 2014
Priority date	Feb 5, 2013
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

A method for manufacturing a fiber reinforced composite by means of a vacuum assisted resin transfer molding, comprising the steps of placing a fiber material in a mold, placing a flow distribution medium onto the fiber material, and covering the fiber material ( 1 ) and the flow distribution medium with a vacuum foil for forming a closed mold cavity between the mold and the vacuum foil is described. It is characterized in using a flow distribution medium with a thickness depending on a pressure gradient over the vacuum foil.

First claim

The invention claimed is:

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.

Assignees

• Siemens Ag

Inventors

• Grove-Nielsen Erik

Classifications

• B29C67/24

  characterised by the choice of material · CPC title

• B29C70/443 Primary

  and impregnating by vacuum or injection · CPC title

• B29C70/44 Primary

  using isostatic pressure, e.g. pressure difference-moulding, vacuum bag-moulding, autoclave-moulding or expanding rubber-moulding · CPC title

• C08G63/00

  Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule (polyester-amides C08G69/44; polyester-imides C08G73/16) · CPC title

• C08F10/06

  Propene · CPC title