Blade Preform Verification via 2D X-Ray Neutral-Fiber Detection

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Solution Overview

Problem

Existing methods for verifying the positioning of fiber preforms in turbomachine blades using X-ray tomography are imprecise due to inaccuracies in detecting the neutral fiber, affecting the integrity and homogeneity of the composite material.

Innovation Solution

A method involving 2D tomographic projections and image processing to locate the neutral fiber by accumulating 2D images along the Y axis, determining gray level profiles, and filtering to enhance precision, followed by comparison with theoretical dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If X-ray tomography is used to detect the neutral fiber, then the blade integrity can be verified, but the detection accuracy is imprecise due to capturing only fragments of glass tracers

Engineering Contradiction:
Improvedetection accuracy of neutral fiberVSAvoidverification of preform positioning
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent divides the detection process into multiple 2D tomographic projections taken at different angles, then accumulates these projections to reconstruct the neutral fiber position. This segmentation of the detection process into multiple views allows for more accurate reconstruction compared to a single fragmented view, resolving the contradiction between measurement precision and reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from 3D tomographic volume reconstruction to 2D projection accumulation along the Y-axis. By accumulating 2D projections and determining gray level profiles, the method achieves more precise neutral fiber localization than traditional 3D reconstruction, improving both measurement precision and verification reliability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If 3D X-ray computed tomography is used to reconstruct the neutral fiber, then the blade integrity can be assessed, but the process is time-consuming and resource-intensive

Engineering Contradiction:
Improveneutral fiber positioning measurementVSAvoidverification process time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts only the necessary information (neutral fiber position) from the 2D tomographic projections by accumulating projections and analyzing gray level profiles. This extraction approach avoids the computationally intensive full 3D reconstruction while achieving the same verification goal, significantly reducing processing time and resource requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of performing complete 3D tomographic reconstruction, the patent uses partial action by accumulating 2D projections along one dimension (Y-axis) to obtain sufficient information for neutral fiber positioning. This partial approach achieves the verification objective with reduced computational effort and time.

Inventive Principle:
Principle #16Partial or excessive action

3Ease of manufacture

If glass tracers are positioned on the preform surface, then the preform positioning can be visually identified, but the detection of neutral fiber remains inaccurate

Engineering Contradiction:
Improvepreform positioning identificationVSAvoidneutral fiber location accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent uses 2D tomographic projections as an intermediary to bridge the gap between the visible glass tracers and the neutral fiber position. By accumulating these projections and analyzing gray level profiles, the method accurately determines neutral fiber location based on the tracer positions, resolving the contradiction between ease of identification and measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 detection accuracy, repeatability, and reduces resource requirements by providing precise measurement of the neutral fiber positioning, ensuring high-quality control of blade integrity.

Implementation Method 1

acquisition of 2D tomographic projections of the blade by means of an imaging system comprising an X-ray source, each projection being acquired according to a given orientation of the X-ray source relative to the blade

Methodology Applied
Scientific EffectX-ray: X-Ray

Data Source

PatentEP4147033B1Verifying the positioning of a fibrous preform in a blade
Publication Date: 2025.07.16 SAFRAN AIRCRAFT ENGINES SAS
  • EP4147033B1 patent drawingFigure 1
  • EP4147033B1 patent drawingFigure 2a~2b
  • EP4147033B1 patent drawingFigure 3~4

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.