Elastomeric Bulkhead Attachment for Wind Turbine Blade Root Ovalisation
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Solution Overview
Problem
Wind turbine blades experience large loads during operation, causing the inboard part to ovalise and putting stress on the glue bonding between the bulkhead and the inner blade wall, which can lead to the bulkhead being torn loose, and the existing solutions with steel or fibre-reinforced composite flanges are difficult to mount and prone to similar stress issues.
Innovation Solution
A wind turbine blade with a bulkhead and attachment part combination where the attachment part is made of elastomeric material, allowing for easy mounting and flexibility to counteract ovalisation, and providing strength to secure the bulkhead without pre-stressing it away from the inner blade wall, while also ensuring a watertight seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the bulkhead is glued directly onto the inner blade wall, then the mounting is simple, but the bulkhead may be torn loose due to loads from blade ovalisation
Solution Approach 1:
The patent applies this principle by using an elastomeric attachment part instead of rigid glue bonding. The elastomeric material acts as a flexible element that can deform under load from blade ovalisation, preventing the bulkhead from being torn loose while maintaining secure attachment. This flexible intermediary layer absorbs the mechanical stress that would otherwise compromise the rigid glue bond.
Solution Approach 2:
The patent changes the material parameter from rigid (glue) to elastomeric (flexible material). This parameter change allows the attachment part to dynamically adapt to the varying loads experienced during blade operation, particularly the ovalisation forces, thereby maintaining both simplicity of mounting and reliability under load.
2Strength
If a steel or fibre-reinforced composite flange is used to mount the bulkhead, then the attachment strength is improved, but the mounting becomes difficult and tedious
Solution Approach 1:
The elastomeric attachment part functions as a flexible element that provides sufficient attachment strength while being easy to install. The flexibility of the elastomeric material allows it to be conveniently positioned and secured without the complex mounting procedures required for rigid flanges, thus maintaining both strength and ease of operation.
Solution Approach 2:
The patent uses an elastomeric material that combines the properties of flexibility with adequate mechanical strength. This composite approach creates an attachment part that is both strong enough to secure the bulkhead reliably and flexible enough to be easily installed, avoiding the difficulties associated with steel or fibre-reinforced composite flanges.
3Strength
If a stiff flange is used to mount the bulkhead, then the attachment is secure, but it becomes difficult to mount inside the wind turbine blade
Solution Approach 1:
The elastomeric attachment part's flexibility enables it to be easily maneuvered and installed within the confined space of the blade interior. Despite this flexibility, it provides secure attachment when positioned, solving the contradiction between mounting accessibility and attachment security.
4Strength
If the attachment part is made rigid to carry loads, then the load-bearing capacity is sufficient, but it cannot accommodate blade ovalisation without tearing loose
Solution Approach 1:
The elastomeric attachment part inherently provides the adaptability needed to accommodate blade ovalisation through its flexible nature, while simultaneously maintaining sufficient load-bearing capacity to carry the bulkhead and withstand operational loads. This eliminates the need for rigid structures that would tear loose under deformation.
Solution Approach 2:
The patent applies dynamics by using a material that can dynamically adjust its shape and position in response to blade deformation. The elastomeric attachment part moves and deforms with the blade during ovalisation, maintaining continuous contact and load-bearing capacity without tearing loose, thus providing both strength and adaptability.
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 elastomeric attachment part allows for easy handling and secure mounting of the bulkhead, preventing debris entry and providing necessary strength to carry loads, including workers, while absorbing forces from ovalisation, thus enhancing the durability and maintenance accessibility of the wind turbine blade.
Implementation Method 1
the elastomeric material provides enough flexibility to counteract ovalisation of the blade root without the attachment part being torn loose from the blade wall
Data Source
AI summary
A wind turbine blade (10) for a rotor of a wind turbine (2) having a substantially horizontal rotor shaft is disclosed. The rotor comprises a hub (8), from which the blade (10) extends substantially in a radial direction when mounted to the hub (8), the blade having a longitudinal direction (r) with a tip end (16) and a root end (14) and a transverse direction. The wind turbine blade comprises a blade shell defining a profiled contour of the blade and having an inner shell wall, wherein the blade is provided with a bulkhead mounted to the inner shell wall at the root end of the blade via an attachment part, the bulkhead comprising a first side and a second side. The attachment part is integrally formed with or connected to the bulkhead, and the attachment part comprises an elastomeric material.