Tapered Core Element Permeability Gradient for Polymer Infusion
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Solution Overview
Problem
In the manufacturing of fibre-reinforced polymer materials through infusion processes, the transition area between fibre layers and core elements can lead to uneven polymer distribution, causing race tracking and resulting in weak points in the finished product, such as visible white stripes on the surface.
Innovation Solution
The core element is composed of a first core part with higher permeability and a second core part with lower permeability, where the first core part is positioned between the centre line and the second core part, allowing for even polymer distribution and reducing the risk of weak points by minimizing race tracking into flow channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a tapered edge section of the core element is wedged into the fibre insertion to achieve a gradual transition, then the transition between fibre layers and core element is improved, but liquid polymer may race track into flow channels of the tapered edge section, creating reduced polymer content and weak points in the product
Solution Approach 1:
The core element is divided into a first core part with higher permeability and a second core part with lower permeability. This segmentation allows different regions of the core element to have different polymer absorption characteristics, preventing race tracking while maintaining gradual transition. The first core part acts as a buffer zone that evenly distributes polymer flow before it reaches the second core part's flow channels.
Solution Approach 2:
Different parts of the core element are given different permeability properties. The first core part has higher permeability to encourage even polymer distribution, while the second core part has lower permeability to control polymer flow into flow channels. This local differentiation of material properties resolves the contradiction between transition uniformity and product strength.
2Device complexity
If the cross-sectional area of porous fibre material is reduced over the tapered edge section of the core element, then the transition area is compacted, but liquid polymer flow speeds up and races into flow channels, creating weak points
Solution Approach 1:
The permeability parameter of the core element is changed in different regions. The first core part has higher permeability to slow down and distribute polymer flow evenly, while the second core part has lower permeability to control flow into channels. This parameter change prevents the race tracking effect that would otherwise occur due to reduced cross-sectional area.
3Device complexity
If a single permeability value is used for the core element, then the structure is simple, but polymer distribution becomes uneven and race tracking occurs
Solution Approach 1:
The core element is designed with non-uniform permeability, where the first core part has higher permeability and the second core part has lower permeability. This local quality differentiation ensures even polymer distribution throughout the core element, preventing race tracking while maintaining a relatively simple overall structure.
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 solution ensures a more uniform polymer distribution, reducing the occurrence of weak points and enhancing the structural integrity of the finished fibre-reinforced polymer products, such as wind turbine blades.
Implementation Method 1
the surface of the first core part has a higher permeability to liquid polymer than that of the surface of the second core part so that, during infusion, liquid polymer penetrates the surface of the first core part more readily than it penetrates the surface of the second core part
Implementation Method 2
the tapered edge section of the at least one core element is wedged in between the fibre layers and thereby into the fibre insertion
Implementation Method 3
liquid polymer is infused into the mould cavity, so that it propagates through the stacked fibre layers and into the flow channels of the at least one core element
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A plurality of fibre layers is stacked to form a fibre insertion (19) extending in a longitudinal direction of the shell part to be manufactured, whereby a core element (21) having a tapered edge section (22) is arranged along the fibre insertion, The fibre layers are stacked so that the tapered edge section of the core element is wedged into the fibre insertion. The core element is composed by a first and a second core part (27, 28) that are arranged along each other. The first core part forms at least part of the tapered edge section of the core element. The surface of the first core part has a higher permeability to liquid polymer than that of the surface of the second core part so that, during infusion, liquid polymer penetrates the surface of the first core part more readily than it penetrates the surface of the second core part.