Wind Turbine Blade Subsurface Void Repair Method
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Solution Overview
Problem
Conventional repair methods for wind turbine blades are time-consuming, labor-intensive, and result in inconsistent and suboptimal structural strength, especially for on-site repairs, as they disrupt airflow and degrade aerodynamic performance.
Innovation Solution
A method involving non-destructive defect detection, drilling fill and vent holes, injecting a flowable bonding material, and reinforcing with mechanical fasteners to create a structurally sound repair zone that maintains aerodynamic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional grind/over-laminate repair procedure is used, then structural strength is improved, but repair time and labor are significantly increased
Solution Approach 1:
The repair process is segmented into distinct phases: drilling fill holes, injecting bonding material, drilling vent holes, and installing mechanical fasteners. This segmentation allows parallel execution of tasks and eliminates sequential dependencies present in conventional methods, reducing overall repair time while maintaining structural integrity
Solution Approach 2:
Fill holes are drilled and bonding material is injected before finalizing the repair structure. This preliminary action prepares the defect zone in advance, allowing mechanical fasteners to be installed subsequently without requiring extensive surface preparation or grinding operations that would extend the repair timeline
2Strength
If conventional grind/over-laminate repair procedure is used, then structural strength is improved, but labor intensity is significantly increased
Solution Approach 1:
The repair procedure is divided into discrete, manageable steps that can be performed by standard technicians without requiring specialized skills in surface preparation, grinding, or laminate application. Each segment (drilling, injecting, fastening) is straightforward and reduces dependence on highly skilled labor
Solution Approach 2:
The conventional mechanical process of grinding and manual laminate application is replaced with a simplified system using drill holes, injectable bonding material, and mechanical fasteners. This substitution eliminates labor-intensive operations while ensuring consistent structural outcomes
3Loss of time
If drill and fill technique is used, then repair time is reduced, but structural strength and consistency are compromised
Solution Approach 1:
The simple drill and fill approach is enhanced by segmenting the process into fill hole drilling, bonding material injection, vent hole drilling, and mechanical fastener installation. This segmentation maintains the time efficiency of the original method while adding structural reinforcement elements that ensure consistent and optimal strength
Solution Approach 2:
The repair structure combines bonding material (chemical bond) with mechanical fasteners (physical connection) to create a composite repair system. This composite approach leverages both adhesive bonding and mechanical interlocking to achieve superior and consistent structural strength compared to drill and fill alone
4Strength
If over-laminate ply is added for additional strength, then structural strength is improved, but aerodynamic performance is degraded
Solution Approach 1:
Instead of adding material in the aerodynamic flow direction (which would create surface protrusions), the repair method places mechanical fasteners and bonding material within drilled holes that are flush with the blade surface. This dimensional change moves the reinforcement elements into the subsurface, eliminating aerodynamic interference while maintaining structural strength
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 method allows for efficient, consistent, and structurally sound on-site repairs of wind turbine blades, reducing time and labor while maintaining aerodynamic performance.
Implementation Method 1
A flowable bonding material is then injected into the fill hole until the bonding material flows from the vent hole
Data Source
AI summary
A procedure for repairing subsurface defects in a shell member laminate of a wind turbine blade includes detecting the location and boundary of the subsurface defect and drilling a fill hole from an external surface of the laminate into the defect proximate to a boundary of the defect. A vent hole is drilled from the external surface of the laminate into the defect proximate to an opposite boundary from the fill hole. A flowable bonding material is injected into the fill hole until the bonding material flows from the vent hole. The repair zone is reinforced with at least one mechanical fastener defined through the laminate either within the boundary of the defect or outboard of the boundary of the defect.