Laser Measurement of Wind Turbine Blade Root Bushing Alignment
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Solution Overview
Problem
Current methods for determining defects in wind turbine blade root attachments are inadequate as they fail to provide precise measurements of stud and bushing deformation, particularly the positioning and misalignment of bushing threads, and are costly due to the use of expensive sensors.
Innovation Solution
A method involving the use of reference bores and laser devices to project beams onto reference plates, allowing for the assessment of the relative angular deviation of the stud axis within the blade root bore, enabling accurate measurement of bushing thread axis perpendicularity and deformation, using an adjustable measuring tool with a laser device and comparator to determine defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are used to measure load and blade root attachment, then measurement capability is provided, but cost increases and measurement precision for bushing thread axis positioning is insufficient
Solution Approach 1:
The patent replaces complex sensor-based mechanical measurement systems with a laser-based optical measurement system. The laser device projects beams through reference bores and the adjustable measuring tool to assess stud axis alignment, eliminating the need for expensive sensors while achieving precise measurements of bushing thread axis positioning and perpendicularity.
Solution Approach 2:
The patent uses reference bores with known geometric relationships as copies or references for the actual bushing and stud assembly. By measuring the relationship between the reference bore axis and the stud axis through laser beams, the method obtains precise information about bushing positioning without directly measuring the complex bushing-thread interface, simplifying the measurement approach.
2Measurement precision
If visual inspection during maintenance is performed, then general defect detection is possible, but precise measurement of stud and bushing deformation is not achieved
Solution Approach 1:
The patent performs preliminary actions by first removing the attaching stud from the bushing before measurement. This allows the adjustable measuring tool to be inserted into the bore and properly positioned against the bushing inner wall, enabling precise laser-based measurement of the bushing thread axis and its perpendicularity to the contact surface, which would not be possible with the stud still installed.
3Reliability
If replaced studs and bushings are installed, then defect repair is achieved, but they become broken again due to improper positioning or misalignment
Solution Approach 1:
The patent provides feedback by measuring the actual position and orientation of the bushing thread axis relative to the reference bore and contact surface using laser beams. This feedback information about perpendicularity and alignment can be used to verify or adjust the positioning of replaced studs and bushings, ensuring they are installed correctly and preventing recurrence of breakage due to misalignment.
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 provides reliable, accurate, and cost-effective defect determination in wind turbine blade root attachments, allowing for precise assessment of stud and bushing deformation, improving quality control and reducing the likelihood of reoccurrence of defects.
Implementation Method 1
A measuring laser beam is then projected towards the reference plate impinging thereon. The measuring laser device is fitted within the blade root bore such that the measuring laser beam is in line with the axis of the blade root bore
Data Source
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AI summary
Reference bores (20) are selected in blade extender (200) and one or more reference plates (300; 310) are provided at a height (h1; h2) from extender flange (21). A reference laser device (400, 410) is provided within reference bores (20) which beam (400', 410') impinging on reference plates (300, 310) is in line with bore axis (20'). A blade root bore (10) is selected and a laser device (500) is fitted therein such that a measuring laser beam (500') impinging on plates (300, 310) is in line with axis of blade root bore (10'). The measuring laser beam (500') can be then assessed. A measuring tool (700) is used having a first end (715) to which laser devices (400, 410, 500) can be attached or other devices such as a comparator (600), and a movable second end (720) for being inserted within the corresponding bores (10, 20) with a tight fit.