Composite Structure Infusion Using Cyclic Vacuum and Polyurethane Resin
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vacuum infusion processes for manufacturing large composite structures, such as wind turbine blades, face challenges with high material waste, complex temperature control, and inefficient resin distribution, leading to increased costs and environmental impact.
Innovation Solution
A method involving cyclic vacuum and polyurethane resin infusion, combined with a resin distribution system and air drying unit, to enhance drying and cooling processes, reducing waste and improving structural strength and production efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If epoxy resin is used with large infusion channels and flow meshes, then resin distribution is controlled, but material waste increases and costs increase
Solution Approach 1:
The patent changes the resin parameters by using polyurethane resin instead of epoxy resin, which has lower viscosity and enables effective infusion without requiring large infusion channels or flow meshes, thereby reducing material waste while maintaining manufacturing precision
Solution Approach 2:
The patent removes the flow meshes and large infusion channels from the system, extracting only the essential resin injection points, which eliminates the associated material waste and cost increases while still achieving proper resin distribution
2Reliability
If the stack is heated to high temperature for dehumidification, then moisture is removed, but temperature control complexity increases
Solution Approach 1:
The patent applies periodic vacuum cycles instead of continuous high-temperature heating, using alternating vacuum and atmospheric pressure phases to remove moisture, which simplifies temperature control while maintaining effective dehumidification
Solution Approach 2:
The patent replaces the thermal field (high-temperature heating) with a mechanical field (vacuum pressure cycling), substituting thermal energy with mechanical pressure changes to achieve moisture removal, thereby reducing temperature control complexity
3Quantity of substance
If cooling time is extended prior to infusion, then resin viscosity is reduced, but production time increases
Solution Approach 1:
The patent changes the resin parameters by selecting polyurethane resin with inherently lower viscosity, which eliminates the need for extended cooling periods to reduce viscosity, thereby maintaining proper resin flow while significantly reducing production time
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
The method reduces manufacturing costs and environmental impact while enhancing structural properties and production efficiency by using polyurethane resin and a simplified drying process.
Implementation Method 1
evacuating air from the stack of layers using a vacuum source
Implementation Method 2
evacuating air from the stack of layers using a vacuum source
Implementation Method 3
heating the stack of layers under vacuum
Implementation Method 4
infusing the stack of layers with a resin matrix material, the resin matrix material being a polyurethane material
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a method of manufacturing a composite structure, a composite structure thereof, a wind turbine with the composite structure and a manufacturing system thereof. The manufacturing system comprises a mould in or on which a stack of layers is laid up, and a resin distribution system is arranged on top of the stack of layers. A resin injection machine and a second vacuum source are both connected to a first valve element arranged in the resin feed lines. A first vacuum source and an air drying unit are both connected to a second valve element arranged in the vacuum lines. During dehumidification, the vacuum pressure is altered between a first and a second vacuum pressure. The relative air moisture content is monitored, and the heating is stopped if it drops below a reference air moisture content. The polyurethane resin is then introduced into the stack of layers and the infused stack of layers are set to cure.