Numerical modelling of the effects of porosity changes on the mechanical properties of nuclear graphite

Berre, Carole Le; Fok, S L; Marsden, Barry; Babout, Laurent; Hodgkins, A; Marrow, James; Mummery, Paul

doi:10.1016/j.jnucmat.2006.02.037

Cited by 53 publications

(37 citation statements)

References 3 publications

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“…The elastic properties of the binder was taken from the nano-indentation test by Berre et al [7]. The elastic modulus of coke filler was estimated using a zero porosity overall modulus and data from radiolytic oxidation experiments in [2] and the resultant value is taken for this analysis.…”

Section: Application Of Eshelby Homogenisation Methods To Elastic Propmentioning

confidence: 99%

Effect of large deformation on creep property evaluation by small-specimen bending tests

Zhuang

Zhou

et al. 2016

International Journal of Pressure Vessels and Piping

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A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. AbstractPhysical mechanisms at different length scales have to be taken into account while predicting the overall failure of nuclear graphite structures of advanced gas cooled graphite reactors. In this paper, the effect of composition of meso graphite phases and porosity on the aggregate elastic properties is predicted using the Eshelby homogenisation method. Results indicate an overall decrease in elastic modulus with an increase in porosity. Subsequently, the moduli at different porosity levels are used to predict the critical strain energy release rates for crack propagation of graphite, and fracture behaviour is studied using compact tension and four point bending tests. Compared to flexural strength at zero porosity level, significant reduction in strength of up to 80% at 30% porosity level is observed. Evolution of flexural strength due to porosity is also compared against available experimental values of graphite from UK nuclear plants.

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Section: Application Of Eshelby Homogenisation Methods To Elastic Propmentioning

confidence: 99%

Effect of large deformation on creep property evaluation by small-specimen bending tests

Zhuang

Zhou

et al. 2016

International Journal of Pressure Vessels and Piping

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“…More recently, the use of these images as the basis for generating finite-element and finite volume models for use in physics-based simulations has gained ground (Abdul-Aziz et al 2006;Berre et al 2006;Watson et al 2006;Notarberardino et al 2008).…”

Section: Illustrative Case Studiesmentioning

confidence: 99%

An efficient approach to converting three-dimensional image data into highly accurate computational models

Young

Beresford-West

Coward

et al. 2008

Phil. Trans. R. Soc. A.

188

121

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Image-based meshing is opening up exciting new possibilities for the application of computational continuum mechanics methods (finite-element and computational fluid dynamics) to a wide range of biomechanical and biomedical problems that were previously intractable owing to the difficulty in obtaining suitably realistic models. Innovative surface and volume mesh generation techniques have recently been developed, which convert three-dimensional imaging data, as obtained from magnetic resonance imaging, computed tomography, micro-CT and ultrasound, for example, directly into meshes suitable for use in physics-based simulations. These techniques have several key advantages, including the ability to robustly generate meshes for topologies of arbitrary complexity (such as bioscaffolds or composite micro-architectures) and with any number of constituent materials (multi-part modelling), providing meshes in which the geometric accuracy of mesh domains is only dependent on the image accuracy (image-based accuracy) and the ability for certain problems to model material inhomogeneity by assigning the properties based on image signal strength. Commonly used mesh generation techniques will be compared with the proposed enhanced volumetric marching cubes (EVoMaCs) approach and some issues specific to simulations based on threedimensional image data will be discussed. A number of case studies will be presented to illustrate how these techniques can be used effectively across a wide range of problems from characterization of micro-scaffolds through to head impact modelling.

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“…The most significant effects are seen in the Young's modulus and thermal conductivity; both reduce by more than half for a 30% porous graphite as compared to a completely non-porous control specimen [4,5]. Scanning electron microscopy (SEM) can be used to measure the shape and size of filler and binder phases and the size, shape and distribution of the larger pores; particle sizes have been found to vary from ca.…”

Section: Introductionmentioning

confidence: 99%

Micro to nanostructural observations in neutron irradiated nuclear graphites PCEA and PCIB

Freeman

Mironov

Windes

et al. 2017

Journal of Nuclear Materials

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a b s t r a c tThe neutron irradiation-induced structural changes in nuclear grade graphites PCEA and PCIB were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), selected area electron diffraction (SAED) and electron energy loss spectroscopy (EELS). The graphite samples were irradiated at the Advanced Test Reactor at the Idaho National Laboratory. Received doses ranged from 1.5 to 6.8 displacements per atom and irradiation temperatures varied between 350 C and 670 C.XRD and Raman measurements provided evidence for irradiation induced crystallite fragmentation, with crystallite sizes reduced by 39e55%. Analysis of TEM images was used to quantify fringe length, tortuosity, and relative misorientation of planes, and indicated that neutron irradiation induced basal plane fragmentation and curvature. EELS was used to quantify the proportion of sp 2 bonding and specimen density; a slight reduction in planar-sp 2 content (due to the buckling basal planes and the introduction of non-six-membered rings) agreed with the observations from TEM.

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Numerical modelling of the effects of porosity changes on the mechanical properties of nuclear graphite

Cited by 53 publications

References 3 publications

Effect of large deformation on creep property evaluation by small-specimen bending tests

Effect of large deformation on creep property evaluation by small-specimen bending tests

An efficient approach to converting three-dimensional image data into highly accurate computational models

Micro to nanostructural observations in neutron irradiated nuclear graphites PCEA and PCIB

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