Wind Turbine Blade Shear Web Bonding with Compressible Spacers
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Solution Overview
Problem
The existing methods for manufacturing wind turbine blades, particularly the two-stage join-up process, are time-consuming and prone to inconsistencies and dis-bonds due to challenges in achieving even adhesive compression and thermal expansion issues, while a one-stage join-up lacks quality control and consistency in bond lines.
Innovation Solution
The use of bond spacers made from compressible materials like closed-cell polyethylene terephthalate (PET) between the mounting flanges and half shells to ensure equal compression and plastic deformation, allowing for simultaneous bond line formation and curing, thereby maintaining even adhesive thickness and preventing dis-bonds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a two-stage join-up process is used to bond the shear web to half shells, then consistent and high quality bond lines can be achieved using a jig, but the production time increases due to adhesive curing time between stages
Solution Approach 1:
The patent applies preliminary action by positioning the shear web and applying adhesive in advance while the mould is open, then using bond spacers to maintain precise positioning before closing the mould. This allows the bonding process to be prepared in advance without requiring a separate curing stage before closing, thus improving production speed while maintaining bond quality.
Solution Approach 2:
The patent introduces bond spacers as intermediary elements between the shear web mounting flanges and the half shells. These spacers serve as mediators that maintain consistent spacing and enable proper adhesive distribution, allowing high-quality bond lines to be achieved in a one-stage process without requiring a jig or two-stage curing approach.
2Productivity
If a one-stage join-up process is used to bond the shear web simultaneously to both half shells, then production time is reduced, but achieving consistent and high quality bond lines becomes challenging without a jig
Solution Approach 1:
Bond spacers are introduced as intermediary elements that enable one-stage join-up while maintaining bond line consistency. These spacers are positioned between the shear web mounting flanges and the half shells, providing mechanical support and maintaining precise spacing during the bonding process, thus achieving both high productivity and manufacturing precision in a single stage.
Solution Approach 2:
The patent changes the physical state and properties of the bond spacers during the process. The spacers are initially in a compressible state to allow positioning and adhesive application, then undergo compression during mould closing to achieve the final bond line thickness. This parameter change enables the spacers to serve multiple functions in maintaining bond consistency throughout the one-stage process.
3Ease of manufacture
If the second mould half is positioned on the first mould half, then the half shells are joined together, but the second half shell releases from the mould half due to gravity causing gaps and uneven adhesive compression
Solution Approach 1:
Bond spacers serve as intermediary elements that prevent the second half shell from releasing from the mould half during the joining process. These spacers are positioned to provide mechanical support and maintain contact between the half shell and mould half, eliminating gaps and ensuring uniform adhesive compression despite gravitational forces.
Solution Approach 2:
The patent applies preliminary anti-action by using bond spacers to counteract the gravitational force that causes the second half shell to release from the mould half. The spacers are positioned in advance to provide opposing force against gravity, preventing the release and maintaining proper positioning throughout the bonding process.
4Reliability
If heat is applied to cure the adhesive, then the adhesive cures to form strong bonds, but thermal expansion causes the second half shell to move back towards the mould half causing dis-bonds
Solution Approach 1:
Bond spacers serve as intermediary elements that maintain stable spacing between the shear web and half shells during thermal curing. These spacers compensate for thermal expansion by providing mechanical constraint, preventing the half shell from moving back towards the mould half and causing dis-bonds, thus maintaining bond line integrity while the adhesive cures.
Solution Approach 2:
The patent applies beforehand cushioning by using compressible bond spacers that anticipate and compensate for thermal expansion during curing. The spacers are positioned in advance to provide cushioning force that counteracts the expansion forces, preventing dis-bonds before they can occur during the heating and curing process.
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 approach enhances the consistency and quality of bond lines in both one-stage and two-stage join-up processes, reducing production time and minimizing dis-bonds by ensuring equal adhesive compression and centralizing the shear web between half shells, thus improving manufacturing efficiency and blade integrity.
Implementation Method 1
The weight of the second half shell and second mould half bears down on the shear web and the first half shell. This causes the adhesive to compress between the various parts.
Implementation Method 2
Once the adhesive is cured, the completed blade may be removed from the mould.
Implementation Method 3
when heat is applied to cure the adhesive, thermal expansion may cause the second half shell to move back towards the mould half
Implementation Method 4
when the second mould half is positioned on top of the first mould half, the second half shell tends to release partially or fully from the second mould half (under the action of gravity)
Data Source
AI summary
A wind turbine blade and associated method of manufacture is described. The blade comprises an outer shell formed of first and second half shells joined together. A shear web is arranged inside the outer shell. The shear web has a web panel disposed between first and second longitudinally-extending mounting flanges. The shear web is bonded to inner surfaces of the respective half shells via a first adhesive bond line between the first mounting flange and the inner surface of the first half shell and a second adhesive bond line between the second mounting flange and the inner surface of the second half shell. One or more bond spacers are provided in the second bond line, and optionally in the first bond line. The bond spacers are compressed between a shear web mounting flange and an inner surface of a half shell and are plastically deformed. The method of making the shear web involves compressing and the one or bond spacers in the bond line(s) such that they undergo plastic deformation. This results in high quality bond lines.