Wind Turbine Blade Root Fixation via Enveloping Fibre Bands
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Solution Overview
Problem
Fibre-reinforced plastic wind turbine blades face issues with stress concentration and fatigue due to high load cycles at the blade root-hub junction, leading to reduced blade lifespan and limitations in blade size.
Innovation Solution
Incorporation of fibre bands that envelop and grip inserts within the blade laminate, distributing load over a larger area and facilitating smooth stress transmission between the blade and hub, thereby enhancing durability and allowing for larger blade construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fibre-reinforced plastic blades are joined to the hub using traditional inserts and screws, then the blade can be securely fixed to the hub, but stress concentration and fatigue problems occur at the blade root-hub junction
Solution Approach 1:
The patent introduces an intermediate layer of fibre bands wrapped around the inserts at the blade root. These fibre bands act as a mediator between the metal inserts and the composite blade structure, distributing stresses more evenly and preventing stress concentration at the blade-hub junction, thereby resolving the contradiction between secure fixation and stress resistance
Solution Approach 2:
The patent employs composite materials by wrapping fibre bands (such as carbon or glass fibres) around the metal inserts and embedding them in resin. This creates a hybrid composite structure that combines the strength of metal inserts with the stress-distributing properties of fibre-reinforced composites, enhancing both reliability and stress resistance
2Productivity
If larger wind turbine blades are constructed to meet increasing energy demands, then energy generation capacity increases, but stress concentration problems worsen at the blade root-hub junction
Solution Approach 1:
The fibre bands wrapped around the inserts serve as an intermediary stress-distribution mechanism that allows larger blades to be connected to the hub without suffering from excessive stress concentration. This intermediary layer enables the scaling up of blade size while maintaining reliability by preventing fatigue failure at the critical blade root-hub junction
3Duration of action of stationary object
If fibre bands are added to wrap around the inserts, then stress distribution improves and blade lifespan extends, but the manufacturing process becomes more complex
Solution Approach 1:
The fibre bands are wrapped around the inserts during the blade manufacturing process before the final curing stage. This preliminary action integrates the stress-distribution feature into the manufacturing process itself, rather than requiring a separate post-processing step, thereby extending blade lifespan while limiting the increase in manufacturing complexity
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 fibre bands reduce local stresses, extend blade lifecycle, and facilitate the construction of larger blades by improving the stress distribution and durability of the blade-hub connection.
Implementation Method 1
fibre bands which grip in an enveloping manner the inserts
Implementation Method 2
fibre bands which grip in an enveloping manner the inserts and are disposed intercalated in the blade laminate
Implementation Method 3
Wind turbine blades are generally laminated composite material, which is formed by several layers of reinforced material joined by a resin
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The root (1) of the blade or the inner structure (17) of the blade comprises means for connecting to the hub, arranged between lamination sheets (2, 3, 18, 19), consisting of a plurality of inserts (4.1, 4.2, 4.3), and used to receive a fixing element associated with the hub, facilitating the coupling of the blade to the hub of the wind turbine. Compact, long and enveloping strips of fibres (7) hug the inserts (4.1, 4.2, 4.3), forming assemblies embedded between the lamination sheets (2, 3, 18, 19), wherein the strips of fibres (7) ensure the progressive transmission of forces between the blade and the hub.