Composite Blade Preform Position Verification Using X-Ray Tomography
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Solution Overview
Problem
Existing methods for verifying the positioning of fibrous preforms in turbomachine blades made of composite material are inaccurate, particularly due to incomplete detection of glass tracers using X-ray tomography, leading to potential non-compliance in fiber volume rate and material integrity.
Innovation Solution
A method involving 2D tomographic projections using an X-ray source, accumulating these projections along the axis Y to form a 2D image, determining grayscale profiles along the axis Z, and processing these profiles to locate the neutral fiber's position accurately, followed by filtering and comparing with theoretical dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If X-ray tomography is used to detect glass tracers in the blade, then the positioning of the preform can be checked, but the detection is incomplete and inaccurate, capturing only scraps of tracers rather than the full neutral fiber
Solution Approach 1:
The patent transitions from conventional 2D planar imaging to 3D tomographic imaging by acquiring multiple projections at different angles and reconstructing them. This dimensional change enables complete visualization of the neutral fiber throughout the blade volume, eliminating the information loss inherent in single-plane detection methods
Solution Approach 2:
The detection process is divided into multiple angular projections (typically 180-360 views), with each projection capturing a different cross-section of the blade. The neutral fiber position is determined by analyzing the spatial distribution of glass tracer signals across these segmented views, allowing accurate 3D localization that overcomes the limitations of any single projection
2Measurement precision
If conventional X-ray tomography with 3D reconstruction is used, then the neutral fiber position can be assessed, but the processing time is long and computational resources are intensive
Solution Approach 1:
The patent extracts and utilizes only the essential information needed for neutral fiber positioning from the tomographic data, rather than performing complete 3D reconstruction of the entire blade volume. By focusing computational effort on tracking the glass tracer signal distribution along the neutral fiber path, the method achieves accurate positioning with significantly reduced processing time
Solution Approach 2:
Instead of reconstructing the entire 3D volume with full computational detail, the method applies partial reconstruction focused specifically on regions containing glass tracers. This selective approach performs sufficient reconstruction only where needed for neutral fiber detection, eliminating unnecessary computational overhead in other blade regions
3Shape
If the preform is deposited in a variable-thickness mold, then the aerodynamic profile of the blade is achieved, but the positioning must be extremely precise to maintain homogeneous material integrity and compliant fiber volume rate
Solution Approach 1:
Glass tracers are incorporated into the preform during its manufacturing process, positioned along the neutral fiber path before the preform is placed in the mold. This preliminary inclusion of detection markers enables post-manufacturing verification of positioning accuracy, allowing detection and correction of positioning deviations that would affect fiber volume rate compliance in the variable-thickness blade geometry
Solution Approach 2:
The tomographic detection method provides quantitative feedback on the actual neutral fiber position by tracking glass tracer locations throughout the blade. This feedback information is compared against the theoretical neutral fiber path, enabling assessment of positioning accuracy and verification that fiber volume rate requirements are met in the complex variable-thickness aerodynamic profile
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
Improves accuracy, repeatability, and reduces processing time while ensuring high-precision detection of the neutral fiber's position, enhancing the integrity and compliance of the manufactured blades.
Implementation Method 1
acquiring 2D tomographic projections of the blade by means of an imaging system comprising an X-ray source
Data Source
AI summary
The invention relates to a method for verifying the positioning of a fibrous preform in a blade, the blade having been obtained by injecting a resin into a mould having the shape of a blade and in which a preform has been placed, the blade extending in an orthonormal blade frame of reference X, Y, Z, the blade comprising a blade root extending longitudinally along an axis X, a vane extending from the blade root along an axis Z, the blade having a thickness defined along an axis Y, the preform comprising glass tracers positioned at the surface of the preform, the centre of the tracers defining a neutral axis located at a height along the axis Z in the direction defined by the axis X, the method comprising the following steps: the acquisition (E31) of tomographic 2D projections of the blade using an imaging system comprising an X-ray source, each projection being acquired at a given orientation of the X-ray source with respect to the blade; the combining (E32, E32a, E32b) of the 2D projections in the direction of the axis Y so as to obtain a cumulative 2D image in the directions X and Z; the determining (E33), for each pixel column defined in the direction of the axis Z, of a greyscale profile; the processing (E34) of each of the profiles obtained so as to locate the position, in Z, of the neutral axis in the direction of the axis X.