Computed Tomography Fatigue Damage Detection
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Solution Overview
Problem
Current methods for detecting fatigue damage in materials under cyclic or continuous loading lack precision and fail to provide early detection, especially in materials like plastics, metals, and ceramics, limiting their ability to predict component service life effectively.
Innovation Solution
A non-destructive 3D examination method using computed tomography that involves recording a complete dataset of X-ray images with high angular resolution, synchronizing image acquisition with load cycles, and employing 3D image correlation to detect changes and reconstruct volumes incrementally, allowing for precise tracking of crack propagation and material fatigue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional test methods are used to investigate fatigue damage under cyclic loading, then the testing can be performed with standard equipment, but the detection precision and early detection capability are insufficient
Solution Approach 1:
The patent transitions from conventional 2D surface measurement methods to 3D volumetric imaging using computed tomography. This dimensional change enables detection of internal fatigue damage and crack propagation throughout the entire specimen volume, not just on the surface, thereby significantly improving detection precision without requiring overly complex additional equipment
Solution Approach 2:
The patent performs preliminary high-resolution 3D scanning of the specimen before fatigue testing to establish a reference state. During subsequent cyclic loading, only changes relative to this preliminary state are detected, enabling early detection of fatigue damage before it becomes macroscopic. This preliminary action allows for sensitive detection without requiring continuously complex measurement systems
2Reliability
If complete datasets with high angular resolution are recorded continuously during loading, then early detection of fatigue damage is enabled, but the data processing effort increases significantly
Solution Approach 1:
The patent extracts only the essential information needed for fatigue damage detection by comparing current 3D images against the preliminary reference state. Instead of processing complete high-resolution datasets continuously, the system extracts only the changes (damage accumulation, crack propagation) from the reference, dramatically reducing data processing time while maintaining early detection capability
Solution Approach 2:
The patent uses partial action by performing full high-resolution scanning only at the beginning to establish the reference state and at selected intervals during testing. Between these intervals, lighter measurement modes are used, reducing overall data processing requirements while still enabling timely detection of fatigue damage progression
3Measurement precision
If 3D image correlation is used to evaluate sequences of 3D images, then accurate tracking of crack propagation is achieved, but the computational effort increases
Solution Approach 1:
The patent segments the 3D image correlation process by first identifying and tracking specific features (crack tips, damage zones) rather than performing full-volume correlation. This segmentation allows accurate crack propagation tracking by focusing computational resources only on relevant regions, reducing overall computational effort while maintaining high measurement precision
Solution Approach 2:
The patent applies partial action by performing detailed 3D image correlation only in regions where changes are detected (damage zones, crack locations) rather than throughout the entire specimen volume. This selective approach maintains accurate crack propagation tracking in critical areas while minimizing computational effort in unchanged regions
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 early detection of fatigue damage with high spatial and temporal resolution, providing accurate predictions about the service life of components by minimizing data processing and leveraging the increased information content of 3D imaging.
Implementation Method 1
In computed tomography, the interaction between X-rays and the matter of an object to be examined is recorded
Data Source
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AI summary
In the method for data determination for a nondestructive 3D analysis of a test specimen by means of computer tomography, first a reference data record comprising image information of a first sequence of radiography images of a test specimen is provided, the first sequence of radiography images having a first average angle increment ?a. Then, image information of a second sequence of radiography images of the test specimen, which has a first state, are generated with an average angle increment ?ß, the second angle increment ?ß being larger than the first angle increment ?a. Thereafter, the respective image information of the second sequence of radiography images is compared with the angularly associated image information of the first sequence of radiography images by means of 2D image correlation, so as to obtain a comparison result. If the comparison result, at an angle position ßi of the second sequence, reaches a threshold value, image information of a third sequence of radiography images of the test specimen is generated in regions around the angle position ßi and with a third average angle increment ??, the third angle increment ?? being smaller than the second angle increment ?ß. Finally, the reference data record is updated on the basis of the image information of the third sequence of radiography images so as to obtain an updated reference data record.