Laminated Object Defect Detection via Shearography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for analyzing large laminated objects, such as wind turbine blades, are inefficient in detecting material defects due to high false positive and false negative rates, and require extensive time and labor, especially when dealing with large surfaces where defects are small and not visibly apparent.
Innovation Solution
A method and system utilizing further processing of topographical data obtained through optical interferometry techniques, such as shearography, to accurately identify and localize defects by applying different load states and integrating data, which reduces false positives and negatives, and uses a database for rapid and accurate identification of surface defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If optical inspection techniques such as shearography are used to examine large surfaces, then measuring speed is improved, but measurement precision deteriorates due to false positives and false negatives
Solution Approach 1:
The patent applies parameter changes by transforming the raw shearography data through mathematical operations (Hessian matrix calculation, eigenvalue decomposition) to enhance the detectability of defects. By changing the parameter representation from direct displacement to curvature derivatives and eigenvalue distributions, the method improves both detection speed and precision simultaneously
Solution Approach 2:
The patent replaces manual visual inspection with automated optical interferometry systems. The mechanical/manual process of examining large surfaces is substituted by an automated optical measurement system that uses shearography techniques, achieving both high speed and improved accuracy through algorithmic processing of the optical data
2Measurement precision
If the entire object is divided into small measuring fields to ensure high reliability, then measurement precision is improved, but loss of time increases due to the large number of single measuring fields
Solution Approach 1:
The patent merges multiple small measuring field analyses into a unified global analysis. By calculating the Hessian matrix and eigenvalues across the entire object surface simultaneously, the method combines the reliability benefits of fine-grained measurement with the speed advantages of holistic processing, eliminating the need to sequentially examine numerous small fields
3Ease of operation
If visual examination of the surface is performed to detect fabrication flaws, then ease of operation is improved, but measurement precision deteriorates because many flaws are not visible to the surface
Solution Approach 1:
The patent replaces simple visual examination with automated optical interferometry. The human visual inspection process is substituted by an optical system that uses shearography to detect subsurface defects through their effect on light interference patterns, maintaining operational simplicity while dramatically improving detection capability for non-visible flaws
Solution Approach 2:
The patent introduces an intermediary measurement mechanism - optical interference patterns - that indirectly reveal subsurface defects. Instead of directly observing flaws, the system detects their presence through their influence on light wave interference, enabling detection of defects that are not visually apparent on the surface
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
Enables fast and reliable identification of defect type, severity, and position on large laminated objects, improving the accuracy and efficiency of defect detection and reducing the risk of erroneous signals, thereby enhancing the assessment of structural integrity.
Implementation Method 1
optical interferometry techniques, such as shearography
Implementation Method 2
shearography techniques or speckle interference techniques
Data Source
Figure 1
Figure 2a~2b
Figure 2c~2d
AI summary
The present invention relates to a method of analyzing a laminated object and to a system for analyzing a laminated object. Illustrative embodiments herein relate to optical interferometry techniques for non-destructively analyzing laminated objects with large surface utilized to obtain data relating to the topography of an object under examination and to further process the obtained topographical data so as to identify type and/or severity and/or position of surface defects.