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Dimitrios Sokoutis - One of the best experts on this subject based on the ideXlab platform.

  • interaction between structural inheritance and extension direction during graben and depocentre formation an experimental approach
    Tectonophysics, 2005
    Co-Authors: Laurent Michon, Dimitrios Sokoutis
    Abstract:

    Abstract Analysis of structural rift architecture shows that the graben formation is commonly controlled by the contemporaneous activity of two fault trends with an angular obliquity of approximately 40°. Inspection of the crustal basement and geophysical data reveals that these faults are parallel to inherited oblique crustal and lithospheric discrete fabrics, which are reactivated during the extension event. We conducted experiments at crustal scale to determine the role of the coeval reactivation of such oblique inherited fabrics in the graben and depocentre development. Experimentally the oblique inherited lithospheric faults were simulated by a basal discrete velocity discontinuity (VD) characterised by two different angles (α) with respect to the extension direction at the intersection of the VDs. Our models show that besides the extension direction which induces the formation of Linear or independent en-echelon grabens, the intersection of the two oblique VD segments controls the location of the depocentre and concentrates subsidence. For different stretching direction values, the depocentre geometry varies from strongly asymmetric to symmetric when the stretching direction corresponds to the Bisecting Line of the two VD segments. Applied to the Upper Rhine graben (central segment of the West European rift), our models allow interpretation of the development of the Late Eocene–Oligocene depocentres at the intersection of two main oblique inherited structures, as the result of a constant NW–SE extension direction. Concerning the southern East African rift, the graben geometries and the evolution of the subsidence during the Mio-Pliocene period may be explained by the reactivation of two main Pan-African inherited shear zones with an E–W direction of extension.

  • Interaction between structural inheritance and extension direction during graben and depocentre formation: An experimental approach
    Tectonophysics, 2005
    Co-Authors: Laurent Michon, Dimitrios Sokoutis
    Abstract:

    Analysis of structural rift architecture shows that the graben formation is commonly controlled by the contemporaneous activity of two fault trends with an angular obliquity of approximately 408. Inspection of the crustal basement and geophysical data reveals that these faults are parallel to inherited oblique crustal and lithospheric discrete fabrics, which are reactivated during the extension event. We conducted experiments at crustal scale to determine the role of the coeval reactivation of such oblique inherited fabrics in the graben and depocentre development. Experimentally the oblique inherited lithospheric faults were simulated by a basal discrete velocity discontinuity (VD) characterised by two different angles (a) with respect to the extension direction at the intersection of the VDs. Our models show that besides the extension direction which induces the formation of Linear or independent en-echelon grabens, the intersection of the two oblique VD segments controls the location of the depocentre and concentrates subsidence. For different stretching direction values, the depocentre geometry varies from strongly asymmetric to symmetric when the stretching direction corresponds to the Bisecting Line of the two VD segments. Applied to the Upper Rhine graben (central segment of the West European rift), our models allow interpretation of the development of the Late Eocene–Oligocene depocentres at the intersection of two main oblique inherited structures, as the result of a constant NW–SE extension direction. Concerning the southern East African rift, the graben geometries and the evolution of the subsidence during the Mio-Pliocene period may be explained by the reactivation of two main Pan-African inherited shear zones with an E–W direction of extension. D 2005 Elsevier B.V. All rights reserved.

Laurent Michon - One of the best experts on this subject based on the ideXlab platform.

  • interaction between structural inheritance and extension direction during graben and depocentre formation an experimental approach
    Tectonophysics, 2005
    Co-Authors: Laurent Michon, Dimitrios Sokoutis
    Abstract:

    Abstract Analysis of structural rift architecture shows that the graben formation is commonly controlled by the contemporaneous activity of two fault trends with an angular obliquity of approximately 40°. Inspection of the crustal basement and geophysical data reveals that these faults are parallel to inherited oblique crustal and lithospheric discrete fabrics, which are reactivated during the extension event. We conducted experiments at crustal scale to determine the role of the coeval reactivation of such oblique inherited fabrics in the graben and depocentre development. Experimentally the oblique inherited lithospheric faults were simulated by a basal discrete velocity discontinuity (VD) characterised by two different angles (α) with respect to the extension direction at the intersection of the VDs. Our models show that besides the extension direction which induces the formation of Linear or independent en-echelon grabens, the intersection of the two oblique VD segments controls the location of the depocentre and concentrates subsidence. For different stretching direction values, the depocentre geometry varies from strongly asymmetric to symmetric when the stretching direction corresponds to the Bisecting Line of the two VD segments. Applied to the Upper Rhine graben (central segment of the West European rift), our models allow interpretation of the development of the Late Eocene–Oligocene depocentres at the intersection of two main oblique inherited structures, as the result of a constant NW–SE extension direction. Concerning the southern East African rift, the graben geometries and the evolution of the subsidence during the Mio-Pliocene period may be explained by the reactivation of two main Pan-African inherited shear zones with an E–W direction of extension.

  • Interaction between structural inheritance and extension direction during graben and depocentre formation: An experimental approach
    Tectonophysics, 2005
    Co-Authors: Laurent Michon, Dimitrios Sokoutis
    Abstract:

    Analysis of structural rift architecture shows that the graben formation is commonly controlled by the contemporaneous activity of two fault trends with an angular obliquity of approximately 408. Inspection of the crustal basement and geophysical data reveals that these faults are parallel to inherited oblique crustal and lithospheric discrete fabrics, which are reactivated during the extension event. We conducted experiments at crustal scale to determine the role of the coeval reactivation of such oblique inherited fabrics in the graben and depocentre development. Experimentally the oblique inherited lithospheric faults were simulated by a basal discrete velocity discontinuity (VD) characterised by two different angles (a) with respect to the extension direction at the intersection of the VDs. Our models show that besides the extension direction which induces the formation of Linear or independent en-echelon grabens, the intersection of the two oblique VD segments controls the location of the depocentre and concentrates subsidence. For different stretching direction values, the depocentre geometry varies from strongly asymmetric to symmetric when the stretching direction corresponds to the Bisecting Line of the two VD segments. Applied to the Upper Rhine graben (central segment of the West European rift), our models allow interpretation of the development of the Late Eocene–Oligocene depocentres at the intersection of two main oblique inherited structures, as the result of a constant NW–SE extension direction. Concerning the southern East African rift, the graben geometries and the evolution of the subsidence during the Mio-Pliocene period may be explained by the reactivation of two main Pan-African inherited shear zones with an E–W direction of extension. D 2005 Elsevier B.V. All rights reserved.

Pierre Mouro - One of the best experts on this subject based on the ideXlab platform.

  • crack propagation from a pre existing flaw at a notch root i introduction and general form of the stress intensity factors at the initial crack tip
    International Journal of Fracture, 2000
    Co-Authors: Jean-baptiste Leblond, Pierre Mouro
    Abstract:

    This paper and its companion are devoted to the study of crack kinking from some small pre-existing crack originating from a notch root (the notch root radius being zero). Both the notch boundaries and the initial crack are allowed to be curved; also, the geometry of the body and the loading are totally arbitrary. The ingredients required are knowledge of the stress intensity factors at the initial crack tip and use of a suitable mixed mode propagation criterion. This paper is devoted to the first point, and more specifically to establishing the general (that is, not yet fully explicit) form of the formulae giving these stress intensity factors. The method used is based on changes of scale (homogeneity properties of the equations of elasticity) on the one hand, and on continuity of the displacement and stresses at a given, fixed point with respect to the crack length on the other hand. The formulae derived for the stress intensity factors at the tip of the small crack are of universal value: they apply to any situation, whatever the geometry of the body, the notch and the crack and whatever the loading, the stress intensity factors depending always only upon the `stress intensity factor of the notch' (the multiplicative coefficient of the singular stress field near the notch root in the absence of the crack), the length of the crack, the aperture angle of the notch and the angle between its Bisecting Line and the direction of the crack.

  • Crack propagation from a pre-existing flaw at a notch root. II: Detailed form of the stress intensity factors at the initial crack tip and conclusion
    International Journal of Fracture, 2000
    Co-Authors: Jean-baptiste Leblond, Pierre Mouro
    Abstract:

    This paper pursues the study of crack kinking from a pre-existing crack emanating from some notch root. It was shown in Part I that the stress intensity factors at the tip of the small initial crack are given by universal (that is, applicable in all situations, whatever the geometry of the body and the loading) formulae; they depend only on the `stress intensity factor of the notch' (the multiplicative coefficient of the singular stress field near the apex of the notch in the absence of the crack), the length of the crack, the aperture angle of the notch and the angle between its Bisecting Line and the direction of the crack. Here we identify the universal functions of the two angles just mentioned which appear in these formulae, by considering the model problem of an infinite body endowed with a notch with straight boundaries and a straight crack of unit length. The treatment uses Muskhelishvili's complex potentials formalism combined with some conformal mapping. The solution is expressed in the form of an infinite series involving an integral operator, which is evaluated numerically. Application of Goldstein and Salganik's principle of local symmetry then leads to prediction of the kink angle of the crack extension. It is found that although the direction of the crack is closer to that of the Bisecting Line of the notch after kinking than before it, the kink angle is not large enough for the crack tip to get closer to this Line after kinking, except perhaps in some special situations.

  • crack propagation from a preexisting flaw at a notch root
    Comptes Rendus De L Academie Des Sciences Serie Ii Fascicule B-mecanique Physique Astronomie, 1999
    Co-Authors: Jean-baptiste Leblond, Pierre Mouro
    Abstract:

    Abstract We study crack kinking from a preexisting crack initiated at a notch root. This makes it necessary to evaluate the stress intensity factors at the tip of the initial crack, as a function of the “stress intensity factor of the notch” (the multiplicative coefficient of the singular stress field at the notch root in the absence of the crack), the length of the crack, the aperture angle of the notch and the angle between its Bisecting Line and the direction of the crack. Applying Goldstein and Salganik's well-known principle of local symmetry yields then the prediction of the kink angle of the crack extension. It is found that although the notch is always predominantly loaded in “mode I”, this angle is generally not large enough for the crack tip to get closer to the Bisecting Line of the notch.

Jean-baptiste Leblond - One of the best experts on this subject based on the ideXlab platform.

  • crack propagation from a pre existing flaw at a notch root i introduction and general form of the stress intensity factors at the initial crack tip
    International Journal of Fracture, 2000
    Co-Authors: Jean-baptiste Leblond, Pierre Mouro
    Abstract:

    This paper and its companion are devoted to the study of crack kinking from some small pre-existing crack originating from a notch root (the notch root radius being zero). Both the notch boundaries and the initial crack are allowed to be curved; also, the geometry of the body and the loading are totally arbitrary. The ingredients required are knowledge of the stress intensity factors at the initial crack tip and use of a suitable mixed mode propagation criterion. This paper is devoted to the first point, and more specifically to establishing the general (that is, not yet fully explicit) form of the formulae giving these stress intensity factors. The method used is based on changes of scale (homogeneity properties of the equations of elasticity) on the one hand, and on continuity of the displacement and stresses at a given, fixed point with respect to the crack length on the other hand. The formulae derived for the stress intensity factors at the tip of the small crack are of universal value: they apply to any situation, whatever the geometry of the body, the notch and the crack and whatever the loading, the stress intensity factors depending always only upon the `stress intensity factor of the notch' (the multiplicative coefficient of the singular stress field near the notch root in the absence of the crack), the length of the crack, the aperture angle of the notch and the angle between its Bisecting Line and the direction of the crack.

  • Crack propagation from a pre-existing flaw at a notch root. II: Detailed form of the stress intensity factors at the initial crack tip and conclusion
    International Journal of Fracture, 2000
    Co-Authors: Jean-baptiste Leblond, Pierre Mouro
    Abstract:

    This paper pursues the study of crack kinking from a pre-existing crack emanating from some notch root. It was shown in Part I that the stress intensity factors at the tip of the small initial crack are given by universal (that is, applicable in all situations, whatever the geometry of the body and the loading) formulae; they depend only on the `stress intensity factor of the notch' (the multiplicative coefficient of the singular stress field near the apex of the notch in the absence of the crack), the length of the crack, the aperture angle of the notch and the angle between its Bisecting Line and the direction of the crack. Here we identify the universal functions of the two angles just mentioned which appear in these formulae, by considering the model problem of an infinite body endowed with a notch with straight boundaries and a straight crack of unit length. The treatment uses Muskhelishvili's complex potentials formalism combined with some conformal mapping. The solution is expressed in the form of an infinite series involving an integral operator, which is evaluated numerically. Application of Goldstein and Salganik's principle of local symmetry then leads to prediction of the kink angle of the crack extension. It is found that although the direction of the crack is closer to that of the Bisecting Line of the notch after kinking than before it, the kink angle is not large enough for the crack tip to get closer to this Line after kinking, except perhaps in some special situations.

  • crack propagation from a preexisting flaw at a notch root
    Comptes Rendus De L Academie Des Sciences Serie Ii Fascicule B-mecanique Physique Astronomie, 1999
    Co-Authors: Jean-baptiste Leblond, Pierre Mouro
    Abstract:

    Abstract We study crack kinking from a preexisting crack initiated at a notch root. This makes it necessary to evaluate the stress intensity factors at the tip of the initial crack, as a function of the “stress intensity factor of the notch” (the multiplicative coefficient of the singular stress field at the notch root in the absence of the crack), the length of the crack, the aperture angle of the notch and the angle between its Bisecting Line and the direction of the crack. Applying Goldstein and Salganik's well-known principle of local symmetry yields then the prediction of the kink angle of the crack extension. It is found that although the notch is always predominantly loaded in “mode I”, this angle is generally not large enough for the crack tip to get closer to the Bisecting Line of the notch.

Sandrine Gonin-giraud - One of the best experts on this subject based on the ideXlab platform.

  • Large-scale analysis by SAGE reveals new mechanisms of oncogene action-7
    2011
    Co-Authors: Corinne Bresson, Céline Keime, Claudine Faure, Yann Letrillard, Maud Barbado, Sandra Sanfilippo, Najate Benhra, Olivier Gandrillon, Sandrine Gonin-giraud
    Abstract:

    Copyright information:Taken from "Large-scale analysis by SAGE reveals new mechanisms of oncogene action"http://www.biomedcentral.com/1471-2164/8/390BMC Genomics 2007;8():390-390.Published onLine 26 Oct 2007PMCID:PMC2194726. (X axis) and NTVA (Y axis) libraries is represented on a logarithmic scale. Each point can represent one or more tags. Colour-coding is based on a statistical analysis (Z test [47]), adjusted for multiple testing according to the method proposed by Benjamini and Hochberg [48]. Black dots represent the 110 tags having an adjusted p-value < 0.1. These tags correspond to genes that are significantly differentially expressed between these 2 conditions. Among these genes, 44 are up-regulated (the corresponding points are located below the first Bisecting Line) and 66 are down-regulated (the corresponding points are located above the first Bisecting Line) in T2ECs expressing the transforming form of v-ErbA as compared to T2ECs expressing the non-transforming form of v-ErbA. The gray dots represent all the other tags

  • Large-scale analysis by SAGE reveals new mechanisms of oncogene action-0
    2011
    Co-Authors: Corinne Bresson, Céline Keime, Claudine Faure, Yann Letrillard, Maud Barbado, Sandra Sanfilippo, Najate Benhra, Olivier Gandrillon, Sandrine Gonin-giraud
    Abstract:

    Copyright information:Taken from "Large-scale analysis by SAGE reveals new mechanisms of oncogene action"http://www.biomedcentral.com/1471-2164/8/390BMC Genomics 2007;8():390-390.Published onLine 26 Oct 2007PMCID:PMC2194726. (X axis) and NTVA (Y axis) libraries is represented on a logarithmic scale. Each point can represent one or more tags. Colour-coding is based on a statistical analysis (Z test [47]), adjusted for multiple testing according to the method proposed by Benjamini and Hochberg [48]. Black dots represent the 110 tags having an adjusted p-value < 0.1. These tags correspond to genes that are significantly differentially expressed between these 2 conditions. Among these genes, 44 are up-regulated (the corresponding points are located below the first Bisecting Line) and 66 are down-regulated (the corresponding points are located above the first Bisecting Line) in T2ECs expressing the transforming form of v-ErbA as compared to T2ECs expressing the non-transforming form of v-ErbA. The gray dots represent all the other tags