Image segmentation for phase-contrast hard X-ray CMT of C/C composites

Vignoles, Gérard L.

doi:10.1016/s0008-6223(00)00103-2

Cited by 38 publications

(22 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Images of C/C composites using phase contrast at a single propagation distance had been obtained previously [11]. In this « edge detection regime », a dark/light fringe appears at density jumps.…”

Section: Segmented Images To Compute Effective Propertiesmentioning

confidence: 99%

Direct 3D microscale imaging of carbon–carbon composites with computed holotomography

Coindreau

Vignoles

Cloetens

2003

Nuclear Instruments and Methods in Physics Research Section B:

View full text Add to dashboard Cite

As part of the modelling of CVI (Chemical Vapor Infiltration), one of the processing techniques of Carbon -Carbon composites, a better understanding of the relation between fiber architecture and transport properties is required. An excellent starting point for the porescale modeling of heat and gas transport is the acquisition of 3D images of the porous media through Computed Micro Tomography at various densification stages. Due to the low X-ray absorption rate of light materials such as carbon, a poor image contrast is obtained with absorption tomography. On the other hand, phase contrast imaging is readily feasible using the coherence properties of modern synchrotron beams. Holotomography has been performed on these materials and it provides quantitative density images where fibers and pyrocarbon matrix deposit are easily distinguishable. Such images are appropriate for the pore-scale computation of many effective transport properties.

show abstract

Section: Segmented Images To Compute Effective Propertiesmentioning

confidence: 99%

Direct 3D microscale imaging of carbon–carbon composites with computed holotomography

Coindreau

Vignoles

Cloetens

2003

Nuclear Instruments and Methods in Physics Research Section B:

View full text Add to dashboard Cite

show abstract

“…However, there are possibilities of extracting a full representation of the material phases through image processing techniques. In the case of C/C composites, a first algorithm has been developed for the separation of void (or resin) and solid phases, which display the strongest edge-enhancement effect (21). It consists in a region-growing algorithm, preceded by a hysteresis step which ensures the continuity of the edgeenhancement pattern.…”

Section: Image Acquisition and Processingmentioning

confidence: 99%

Fibre-scale Modeling of C/C Processing by Chemical Vapour Infiltration using Xray CMT Images and Random Walkers

Vignoles

Germain²,

Coindreau³

et al. 2009

ECS Trans.

Self Cite

View full text Add to dashboard Cite

We present a computational tool for the modeling of Chemical Vapor Infiltration of carbon/carbon composites, which is based on 3D images acquired by X-ray Computerized Micro-Tomography with a very fine resolution, such that the fibers are clearly distinguishable from each other. Preliminary image processing is necessary in order to perform segmentation between solid and void phases. Then, morphological and transport properties are computed in the images. Random walkers are used for the simulation of gas transport in continuum and rarefied regimes. The image modification under chemical deposition is handled by a specific surface discretization technique and a pseudo-VOF method. Results are presented and discussed: the notion of infiltrability is introduced as a design tool for the CVI engineer.

show abstract

“…Finally, the developed numerical tools have been tested on a more realistic medium. Carbon fiber cloth stackings, which constitute preforms for C/C composite materials, have been scanned in synchrotron Xray Computerized Microtomography (Coindreau and Vignoles, 2004) with 0.7 µm resolution, resulting in excellent 3D images, thanks to an adequate segmentation procedure (Vignoles, 2001). These highresolution images have been utilized for the estimation of geometrical properties , as well as tortuosities with respect to binary diffusion and Knudsen diffusion Vignoles et al, 2007), on a large number of sub-images.…”

Section: Test Image 2 : 3d Anisotropymentioning

confidence: 99%

Rarefied Pure Gas Transport in Non-isothermal Porous Media: Validation and Tests of the Model

et al. 2008

View full text Add to dashboard Cite

Abstract. Viscous flow, effusion, and thermal transpiration are the main gas transport modalities for a rarefied gas in a macro-porous medium. They have been well quantified only in the case of simple geometries. This paper presents a numerical method based on the homogenization of kinetic equations producing effective transport properties (permeability, Knudsen diffusivity, thermal transpiration ratio) in any porous medium sample, as described e. g.by a digitized 3D image. The homogenization procedure -neglecting the effect of gas density gradients on heat transfer through the solid -leads to closure problems in R 6 for the obtention of effective properties ; they are then simplified using a Galerkin method based on a 21-element basis set. The kinetic equations are then discretized in R 3 space with a finite-volume scheme. The method is validated against experimental data in the case of a closed test tube. It shows to be coherent with past approaches of thermal transpiration. Then, it is applied to several 3D images of increasing complexity. Another validation is brought by comparison with other distinct numerical approaches for the evaluation of the Darcian permeability tensor and of the Knudsen diffusion tensor. Results show that thermal transpiration has to be described by an effective transport tensor which is distinct from the other tensors.

show abstract

Image segmentation for phase-contrast hard X-ray CMT of C/C composites

Cited by 38 publications

References 13 publications

Direct 3D microscale imaging of carbon–carbon composites with computed holotomography

Direct 3D microscale imaging of carbon–carbon composites with computed holotomography

Fibre-scale Modeling of C/C Processing by Chemical Vapour Infiltration using Xray CMT Images and Random Walkers

Rarefied Pure Gas Transport in Non-isothermal Porous Media: Validation and Tests of the Model

Contact Info

Product

Resources

About