Wind Turbine Blade Two-Step Curing for Uniform Shrinkage
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Solution Overview
Problem
The manufacturing of large wind turbine blades is challenged by uneven curing temperatures and spatial variations in resin shrinkage, leading to defects such as deformation, internal stress, and cracks, which are difficult to detect and affect aerodynamic performance and strength.
Innovation Solution
A two-step curing process using a resin flow medium coated with a curing inhibitor is employed, delaying the cure at the interface between the outer shell and load-carrying structure, allowing the load-carrying structure to achieve its natural geometry before adhering to the outer shell, thereby reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single-step curing process is used for the entire blade structure, then the manufacturing process is simple and fast, but uneven curing temperatures occur in thicker parts leading to manufacturing defects
Solution Approach 1:
The curing process is divided into two distinct steps: first curing the outer shell part, then curing the load-carrying structure. This segmentation allows each part to be cured under optimized conditions, preventing the uneven curing temperatures that occur in single-step processes while maintaining overall manufacturing efficiency.
Solution Approach 2:
The outer shell part is cured first before the load-carrying structure. This preliminary action creates a stable base that prevents deformation during subsequent curing, and the resin flow medium with inhibitor delays the curing of the load-carrying structure until the outer shell is ready, ensuring proper timing and temperature control.
2Loss of time
If the load-carrying structure cures immediately after resin infusion, then the curing process is complete faster, but the structure adheres to the outer shell before reaching natural geometry causing internal stress and delamination
Solution Approach 1:
A resin flow medium coated with a curing inhibitor is introduced as an intermediary layer between the outer shell and the load-carrying structure. This intermediary delays the adhesion of the load-carrying structure to the outer shell, allowing the load-carrying structure to reach its natural geometry without constraint before bonding occurs, thus preventing internal stress and delamination.
Solution Approach 2:
The resin flow medium with inhibitor is applied beforehand to delay curing. This preliminary action ensures that the load-carrying structure cures at the optimal time - after reaching its natural geometry - preventing bonding defects while maintaining overall process efficiency.
3Ease of manufacture
If thicker parts of the blade are cured with uniform heating, then the curing process is straightforward, but the edges receive insufficient heat leading to improper shrinkage and manufacturing defects
Solution Approach 1:
Different regions of the blade receive different curing treatments. The outer shell part is cured first with appropriate heat distribution, and then the load-carrying structure is cured. The resin flow medium with inhibitor ensures that edges receive adequate heat exposure time for proper shrinkage while thicker parts are cured in a controlled manner, achieving uniform shrinkage throughout.
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 effectively minimizes manufacturing defects by ensuring uniform curing and natural geometry, enhancing the blade's aerodynamic performance and structural integrity.
Implementation Method 1
the resin flow medium (76) comprises a curing inhibitor
Implementation Method 2
This may lead to manufacturing defects within the part as the degree and timing of shrinkage during the curing process may vary spatially
Data Source
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AI summary
The present invention relates to a method of manufacturing a wind turbine blade using a two-step curing process, wherein the second curing is performed in the presence of a resin flow medium (76) comprising a curing inhibitor.