Rotor Blade Defect Detection Using Pressed Thermal Imaging
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Solution Overview
Problem
Existing methods for detecting imperfections in rotor blades, particularly those made of laminate construction with fiber mats and/or sandwich materials, face inaccuracies in heating and thermal imaging due to variable distances and angles, leading to inefficient detection of undulations and potential damage.
Innovation Solution
A method and device where a thermal radiator and camera are mounted on a displaceable holder pressed against the rotor blade, ensuring constant and reproducible heating and imaging, with adjustable distances and orientations to maintain precise contact and reduce measurement inaccuracies, allowing for accurate detection of inhomogeneities and potential repairs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a deflection and focusing system with sunlight is used to heat the rotor blade, then the heating area can be covered, but the heating uniformity and measurement accuracy deteriorate due to variable distances and angles
Solution Approach 1:
The patent replaces the optical-mechanical deflection and focusing system with a thermal radiator that emits thermal energy directly. This substitution eliminates the need for complex mechanical positioning systems and ensures uniform heating across the rotor blade surface while maintaining measurement accuracy through controlled thermal emission.
Solution Approach 2:
The patent changes the heating mechanism from sunlight-based (dependent on external conditions and geometric positioning) to a controlled thermal radiator system. This parameter change allows for consistent heating uniformity and reproducible measurement conditions, directly addressing the accuracy issues caused by variable distances and angles in the previous system.
2Measurement precision
If point-measuring devices using ultrasonic exciters or microwave technology are used, then detection precision for undulations can be achieved, but the inspection time increases significantly
Solution Approach 1:
The patent replaces point-measuring mechanical and electromagnetic systems with a thermal imaging system. This substitution enables area-wide inspection capability, significantly reducing inspection time while maintaining the ability to detect undulations through thermal image analysis of heat distribution patterns.
Solution Approach 2:
The patent transitions from point-measuring (zero-dimensional or one-dimensional) to area-wide imaging (two-dimensional or three-dimensional) inspection. By using thermal imaging cameras to capture the entire heated surface, the system achieves both comprehensive coverage and rapid inspection, eliminating the time-consuming sequential point-measuring process.
3Adaptability or versatility
If the thermal imaging camera is positioned at variable distances and angles, then the inspection can adapt to surface contours, but heating uniformity and measurement accuracy deteriorate
Solution Approach 1:
The patent employs a movable holder that can dynamically adjust its position and orientation relative to the rotor blade surface. This dynamic capability allows the thermal radiator and camera to adapt to surface contours while maintaining optimal heating uniformity and measurement accuracy through controlled movement.
Solution Approach 2:
The patent incorporates a feedback mechanism where the thermal imaging camera captures thermal images that are analyzed to detect undulations and measurement inaccuracies. This feedback information can be used to adjust the holder position or heating parameters, ensuring both adaptability to surface contours and maintenance of heating uniformity and measurement accuracy.
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 approach provides precise, spatially resolved thermal imaging, enabling effective detection of imperfections and potential damage, reducing test duration and preventing capital losses by ensuring accurate location and extent of undulations without destructive testing.
Implementation Method 1
the rotor blade is locally heated by a heat emitter guided along the rotor blade
Implementation Method 2
the heated area is detected by a thermal imaging camera guided along the rotor blade
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a method and a device for detecting defects in rotor blades (1) which are manufactured in laminate construction with a layer structure of fiber mats and/or sandwich materials in a plastic matrix, wherein the rotor blade (1) is locally heated with a heat radiator (2) guided along the rotor blade (1), the heated area is detected with a thermal imaging camera (3) guided along the rotor blade (1), and irregularities in the thermal image are output using image processing or signal analysis methods, wherein the heat radiator (2) and the thermal imaging camera (3) are arranged on at least one holder (5) which is pressed against the rotor blade (1) during heating and detection.