Inflatable Bag Moulding for Wind Turbine Blade Profiles
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Solution Overview
Problem
Existing methods for manufacturing large wind turbine blades face difficulties due to the complexity of removing mould cores from large and intricately shaped composite fibre blades, which can lead to slipping and alignment issues during the manufacturing process.
Innovation Solution
A method involving an inflatable, collapsible bag is used to press composite fibre layers onto mould surfaces, allowing for easy alignment and fixation, eliminating the need for massive moulds and simplifying the manufacturing process by inflating the bag to form the blade profile in a single step, with optional underpressure or adhesive fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a mould core is used to form the blade profile, then the blade can be manufactured with complex profiles, but the mould core becomes difficult to remove after curing
Solution Approach 1:
The blade manufacturing process is segmented into two parts: the external mould that defines the blade profile and the internal bag that is inflated to form the hollow structure. The bag is divided into multiple sections that can be independently inflated and removed, avoiding the difficulty of removing a single large rigid mould core from a complex blade profile.
Solution Approach 2:
Instead of using a rigid mould core that is difficult to remove, the invention inverts the approach by using a collapsible bag that is inflated from the inside. The bag transitions from a collapsed state (easy to insert) to an inflated state (forms the hollow blade structure), and then back to collapsed state (easy to remove). This inversion of the mould core concept solves the removal difficulty.
2Shape
If composite fibre layers are laid on mould surfaces, then the blade profile can be formed, but the fibre layers may slip and misalign during manufacturing
Solution Approach 1:
The bag is fixed to the mould surface before the composite fibre layers are laid. This preliminary action creates a stable base that prevents the fibre layers from slipping during the manufacturing process. The bag's presence provides immediate mechanical support and positioning reference for the fibre layers.
Solution Approach 2:
The bag serves as an intermediary element between the mould surface and the composite fibre layers. It provides a flexible interface that conforms to the mould surface geometry while supporting the fibre layers, preventing direct contact between the fibres and the rigid mould that could cause slippage.
3Strength
If massive moulds are used to form the blade profile, then the blade structure can be supported, but the manufacturing process becomes complex and difficult to handle
Solution Approach 1:
The invention replaces massive rigid moulds with flexible thin-walled bags that are inflated to form the blade profile. The bag walls, while thin, provide sufficient support when pressurized, and the flexible nature of the bag allows it to conform to complex blade geometries without requiring complex mould mechanisms.
Solution Approach 2:
The invention uses pneumatic pressure (inflating the bag with gas) to provide the structural support that would otherwise require massive rigid moulds. The pressurized bag maintains its shape and provides the necessary support for the composite fibre layers, simplifying the moulding system while maintaining blade structure integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables the efficient manufacturing of hollow wind turbine blades in a single step, preventing slipping and simplifying the removal of the bag after curing, facilitating the production of complex blade profiles without the need for massive moulds, and allowing for easier handling and alignment of fibre layers.
Implementation Method 1
The bag is inflated in such a way, that the first composite fibre layer is pressed to the first mould surface and the second composite fibre layer is pressed to the second mould surface
Implementation Method 2
The bag and the first composite fibre layer are fixed to the first mould surface
Implementation Method 3
optional underpressure or adhesive fixation
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The present invention relates to a method for forming a profile for a hollow component made of composite fibre, in particular a hollow blade for a wind turbine. A first composite fibre layer (101) is laid out on a first mould surface of a first mould element (110), wherein the first mould surface corresponds to a first profile section of the hollow component to be manufactured. A second composite fibre layer (102) is laid out in a second mould surface of a second mould element (120), wherein the second mould surface corresponds to a second profile section of the hollow component to be manufactured. A bag (201) is laid out in a collapsed state onto the first composite fibre layer (101). The bag (201) and the first composite fibre layer (101) are fixed to the first mould surface. The first mould element (110) is coupled to the second mould element (120) in such a way, that the first mould surface and the second mould surface correspond to the profile of the hollow component to be manufactured. The bag (201) is inflated in such a way that the first composite fibre layer (101) is pressed to the first mould surface and the second composite fibre layer (102) is pressed to the second mould surface, so that the first composite fibre layer (101) and the second composite fibre layer (102) are coupled to form the profile to be manufactured.