Expandable Wedge Connector Assembly for Offshore Wind Joints
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Solution Overview
Problem
Existing offshore wind turbine connection methods using bolted flanges are inefficient due to unpredictable preload control, high maintenance requirements, and limited scalability, with large bolts and tools being cumbersome and prone to bending stresses, leading to reduced weld lifespan and poor fatigue resistance.
Innovation Solution
A connector system with a fork-shaped cross section and radially expandable design, featuring a first and second expansion block and wedges, which is axially insertable and expandable to create a clamping contact, optimizing strength-to-size ratio and reducing material usage, weight, and handling difficulties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bolted flanges with large bolts (e.g., M72) are used to connect offshore wind turbine members, then the connection can withstand high loads, but the bolts and tools become heavy and hard to handle
Solution Approach 1:
The connector is divided into multiple segments or modules that can be assembled in a stepwise manner. This segmentation allows the heavy lifting and positioning operations to be performed on smaller, lighter components rather than requiring complete pre-assembly of the entire connector, thereby reducing the weight that must be handled during installation while maintaining the overall connection strength.
Solution Approach 2:
The connector incorporates pre-assembled components and pre-positioned elements that are prepared before installation. This preliminary action allows critical alignment and positioning to be accomplished during manufacturing rather than during field installation, reducing the complexity and weight of tools required on-site while ensuring the connection achieves the necessary strength.
2Ease of operation
If constant torque method is used to tighten bolts, then the tightening process is simple, but the actual preload on bolts becomes unpredictable and varies significantly
Solution Approach 1:
The connector incorporates feedback mechanisms such as load cells, strain gauges, or other sensing elements that provide real-time information about the actual preload being applied to the connection. This feedback allows the tightening process to be monitored and adjusted dynamically, ensuring that the target preload is achieved with high precision while maintaining operational simplicity through automated or semi-automated control systems.
Solution Approach 2:
The invention replaces traditional mechanical torque-based tightening systems with alternative mechanisms such as hydraulic tensioning systems, wedge-based locking mechanisms, or self-tensioning elements. These substitutions eliminate the need for complex torque control while providing more reliable and predictable preload application, improving both ease of operation and reliability simultaneously.
3Strength
If flanges with bolts arranged all around the circumference are used, then the connection can distribute loads, but the gap between adjacent bolts becomes very limited
Solution Approach 1:
The connector transitions from a two-dimensional flange interface to a three-dimensional engagement system. By utilizing radial expansion, axial insertion, or multi-level connection points, the design creates additional spatial dimensions for bolt or connector placement. This allows load distribution across multiple dimensions while maintaining adequate clearance and access space between individual connection elements.
Solution Approach 2:
The connector employs a nested arrangement where smaller connection elements are positioned within or between larger structural components. This nesting allows the connection system to achieve comprehensive load distribution throughout the connector structure while maintaining sufficient gaps between individual fastening points for proper installation and inspection access.
4Strength
If radial displacement of the actuator is used to increase clamping force, then the connection can be secured, but a significant force is required due to the clamping action
Solution Approach 1:
The connector incorporates dynamic elements such as inclined surfaces, cam mechanisms, or progressive engagement features that allow the clamping force to be applied gradually rather than instantaneously. This dynamic approach reduces the peak force required during installation by distributing the load application over time and distance, making the radial displacement operation more manageable while still achieving the necessary clamping force for a secure connection.
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 connector system provides a more efficient, scalable, and lightweight connection with improved fatigue resistance and reduced maintenance needs, maintaining the advantages of previous designs while enhancing strength and compactness.
Implementation Method 1
one or more than one wedge (22, 23) that is arranged in between the first expansion block (20) and the second expansion block (21), and that is configured to be displaced longitudinally relative to the channel (17) to thereby radially expand the connector (18) relative to the channel (17)
Implementation Method 2
pushing, in an expanded state of the connector (18), the first member (10) in a radial direction relative to said channel (17) against the face (15) of the main body (12) of the second member (11) to define a clamping contact and thereby a pre-tensioned connection
Data Source
AI summary
An assembly includes first and second members connected via a connector that is axially insertable into a channel defined by passages of the first and the second member. The connector exhibits a length extending in a longitudinal direction of the channel and includes first and second expansion blocks, and one or more than one wedge between the first expansion block and the second expansion block, and is configured to be displaced longitudinally relative to the channel to thereby radially expand the connector relative to the channel. At a cross section halfway the length of the connector, a cross sectional area and a height of a first expansion block in a radial direction relative to the channel is smaller than a cross sectional area and a height of a second expansion block in said radial direction relative to said channel. A method of assembling such an assembly.