Polyurethane Transition-Piece Gasket for Seawater-Durable Mounting
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Solution Overview
Problem
Existing methods for stabilizing the connection between the upper structure and foundation piles of wind turbines, such as transition pieces and monopiles, are time-consuming, expensive, and lack durability, especially in marine environments, and require materials that can withstand high compression forces and maintain elasticity over time.
Innovation Solution
A polyurethane gasket is used, composed of specific polymeric compounds and additives, which is designed to absorb compression, tension, and shear stresses, maintaining high elasticity and low compression set even in seawater conditions, by mixing organic polyisocyanate with polymeric compounds, chain extenders, and optional fillers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If grouting or bolting is used to fix the transition piece to the monopile, then the connection is stabilized, but the installation process becomes time-consuming and expensive
Solution Approach 1:
The patent changes the material parameter from rigid (grout, bolts) to elastomeric/viscoelastic, allowing the gasket to deform and absorb stresses while maintaining connection stability. This eliminates the need for time-consuming grouting and bolting operations while achieving reliable stabilization through the gasket's inherent elasticity and stress-absorbing properties.
Solution Approach 2:
The patent employs composite material construction by combining elastomeric or viscoelastic materials with specific physical properties (hardness 70-120 Shore A, elongation >100%) to create a gasket that integrates both sealing and stress-absorbing functions. This composite approach replaces multiple separate components (grout + bolts) with a single integrated elastomeric gasket system.
2Reliability
If grouting is used to stabilize the connection, then the transition piece is fixed, but the assembly lacks durability in marine environments over the turbine's lifetime
Solution Approach 1:
The patent changes the material parameter from rigid grout to elastomeric/viscoelastic material with specific properties (hardness 70-120 Shore A, elongation >100%). This enables the gasket to accommodate thermal expansion, contraction, and movement throughout the turbine's service lifetime, maintaining durability in marine environments where rigid grouting would fail due to stress accumulation.
Solution Approach 2:
The patent introduces dynamic properties by using elastomeric or viscoelastic materials that can deform and recover, allowing the gasket to adapt to changing conditions (temperature, stress, movement) throughout the turbine's operational lifetime. This dynamic behavior replaces the static, brittle nature of grout, ensuring long-term durability.
3Ease of manufacture
If conventional materials are used for the gasket, then the installation is simpler, but the gasket fails under high compression forces
Solution Approach 1:
The patent employs composite material construction by combining elastomeric or viscoelastic materials with specific physical properties (hardness 70-120 Shore A, elongation >100%, tear strength >30 N/mm) to create a gasket that integrates both sealing and stress-absorbing functions. This composite approach replaces multiple separate components (grout + bolts) with a single integrated elastomeric gasket system.
Solution Approach 2:
The patent changes the material parameter from rigid (grout, bolts) to elastomeric/viscoelastic, allowing the gasket to deform and absorb stresses while maintaining connection stability. This eliminates the need for time-consuming grouting and bolting operations while achieving reliable stabilization through the gasket's inherent elasticity and stress-absorbing properties.
4Strength
If the gasket material is too soft to absorb stresses, then installation is easier, but it cannot withstand high compression forces; if too hard, it withstands compression but loses elasticity
Solution Approach 1:
The patent optimizes the material parameter by specifying hardness in the range of 70-120 Shore A, which balances compression resistance and elasticity. This parameter range enables the gasket to withstand high compression forces while retaining sufficient elasticity to absorb stresses and accommodate movements, resolving the trade-off between strength and flexibility.
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 gasket provides excellent mechanical stability and durability, with high elongation, low compression set, and minimal hardness change after exposure to seawater, ensuring long-term structural integrity and stability.
Implementation Method 1
the gasket stabilizes the position of the upper structure relative to the pile structure by absorbing compression, tension, and/or shear stresses occurring due to movements of the upper structure and/or the pile structure
Implementation Method 2
mixing (a) organic polyisocyanate, (b) polymeric compounds having at least two isocyanate-reactive hydrogen atoms, (c) chain extenders, (d) catalyst and (e) optionally fillers and/or polyurethane additives, to give a reaction mixture and allow the reaction mixture to cure
Data Source
AI summary
Disclosed herein is a gasket for formfitting the bottom part of an upper structure of a wind turbine, such as a transition piece or a turbine tower, with one or more foundation piles, where the gasket includes a polyurethane obtained by mixing (a) organic polyisocyanate, (b) polymeric compounds having at least two isocyanate-reactive hydrogen atoms, (c) 1 to 12 wt.-%, based on the total weight of components a) to c), of one or more chain extenders, (d) catalyst and (e) optionally fillers and/or polyurethane additives to give a reaction mixture and allowing the reaction mixture to cure where the polymeric compounds having at least two isocyanate-reactive hydrogen atoms (b) include polyetherol obtained by alkoxylation of a difunctional starter molecule (b1) and polyetherol obtained by alkoxylation of a trifunctional starter molecule (b2). Further disclosed herein is a method for mounting a transition piece of a wind turbine to a monopile.