Method of manufacturing a wind turbine blade by embedding a layer of pre-cured fibre reinforced resin
The present invention relates to a method of manufacturing a wind turbine blade or a part of a wind turbine blade. The method comprises arranging at least one layer of uncured resin pre-impregnated fibers, called prepregs, and at least one layer of cured fiber reinforced resin in an at least partly overlaying relationship, and curing the resin of the at least one layer comprising uncured resin. The at least one layer of cured fiber reinforced resin is assembled with at least one layer of uncured resin-preimpregnated fibers prior to being placed on a molding surface. The method may e.g. be used to manufacture a wind turbine blade shell member or a wind turbine blade spar member. The invention further relates to a wind turbine blade shell member or a wind turbine blade spar member manufactured by such a method. The invention further relates to a pre-form for use in a wind turbine blade, the pre-form comprising at least one layer of uncured resin pre-impregnated fibers and at least one layer of cured fiber reinforced resin in an at least partly overlaying relationship.
1. A method of manufacturing a wind turbine blade or a part of a wind turbine blade, the method comprising:
arranging at least one layer of uncured resin pre-impregnated fibres and at least one layer of fully cured fibre reinforced resin in an at least partly overlaying relationship,
applying pressure on the layers arranged together to assemble the layers into a pre-form, the pre-form held together by tackiness of the at least one layer of uncured resin pre-impregnated fibres, the pre-form being assembled before placement of the pre-form on a moulding surface;
handling the pre-form before placement of the pre-form on the moulding surface;
moving the pre-form onto the moulding surface; and
curing the resin of the at least one layer of uncured resin pre-impregnated fibres, thereby manufacturing the wind turbine blade or the part thereof from the pre-form, wherein curing the resin further comprises:
absorbing heat energy from the exothermic process of curing resin with the at least one layer of fully cured fibre reinforced resin while the at least one layer of uncured resin pre-impregnated fibres release heat energy in the exothermic process, thereby minimizing the overall temperature increase that needs to be applied to cure the pre-form and also minimizing a risk of material degradation caused by excessive heat application during the curing.
2. The method according to claim 1 , the method further comprising:
providing an airtight and flexible enclosure over the at least one layer of uncured resin pre-impregnated fibres and the at least one layer of fully cured fibre reinforced resin,
substantially evacuating air present in the enclosure, and
heating the layers in the enclosure for a predefined period of time.
3. The method according to claim 1 , wherein the pressure is applied by use of at least one roller.
4. The method according to claim 1 , wherein the thickness of each layer is between 0.3 mm and 2 mm.
5. The method according to claim 1 , wherein the at least one layer of uncured resin pre-impregnated fibres and the at least one layer of fully cured fibre reinforced resin have substantially the same thickness before assembly.
6. The method according to claim 1 , wherein the fibres are uni-directionally arranged.
7. The method according to claim 1 , wherein the resin and/or the fibres are the same types in the at least one layer of uncured resin pre-impregnated fibres and the at least one layer of fully cured fibre reinforced resin.
8. The method according to claim 1 , wherein the at least one resin is selected from: epoxy, polyester, vinyl ester, and phenol.
9. The method according to claim 1 , wherein the method is used to manufacture a wind turbine blade shell member.
10. The method according to claim 9 , wherein the method is used to manufacture the trailing edge stringer or the connecting stringer of the wind turbine blade shell member.
11. The wind turbine blade shell member manufactured by a method according to claim 9 .
12. The method according to claim 1 , wherein the method is used to manufacture a wind turbine blade spar member.
13. The wind turbine blade spar member manufactured by a method according to claim 12 .