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Jamie J. Kruzic - One of the best experts on this subject based on the ideXlab platform.

  • Crack Tip toughness from vickers Crack Tip Opening displacements for materials with strongly rising r curves
    Journal of the American Ceramic Society, 2011
    Co-Authors: Stefan Fünfschilling, Theo Fett, Rainer Oberacker, Michael J. Hoffmann, Gerold A. Schneider, Paul F. Becher, Jamie J. Kruzic
    Abstract:

    Accurate measurements of the intrinsic Crack-Tip toughness, KI0, are essential to understanding the strength and toughness of bridging ceramics. Furthermore, even the most carefully made R-curve measurements cannot accurately assess this initial toughness point. In this manuscript, both rigorous and approximate methods are proposed for determining KI0 from Crack-Tip Opening displacement (COD) measurements on Vickers indent Cracks for materials with steeply rising R-curves. Such approaches are attractive because of the relative ease of producing indentation Cracks and analyzing the CODs; further, the latter method is of particular interest because it saves considerable computational effort. Both the advantages and limitations of the proposed methods are discussed. Finally, based on applying the above methods to three Si3N4 ceramics, it was concluded that there is a common Crack-Tip toughness of KI0≈2.2±0.3 MPa·√m.

  • Crack‐Tip Toughness from Vickers Crack‐Tip Opening Displacements for Materials with Strongly Rising R‐Curves
    Journal of the American Ceramic Society, 2011
    Co-Authors: Stefan Fünfschilling, Theo Fett, Rainer Oberacker, Michael J. Hoffmann, Gerold A. Schneider, Paul F. Becher, Jamie J. Kruzic
    Abstract:

    Accurate measurements of the intrinsic Crack-Tip toughness, KI0, are essential to understanding the strength and toughness of bridging ceramics. Furthermore, even the most carefully made R-curve measurements cannot accurately assess this initial toughness point. In this manuscript, both rigorous and approximate methods are proposed for determining KI0 from Crack-Tip Opening displacement (COD) measurements on Vickers indent Cracks for materials with steeply rising R-curves. Such approaches are attractive because of the relative ease of producing indentation Cracks and analyzing the CODs; further, the latter method is of particular interest because it saves considerable computational effort. Both the advantages and limitations of the proposed methods are discussed. Finally, based on applying the above methods to three Si3N4 ceramics, it was concluded that there is a common Crack-Tip toughness of KI0≈2.2±0.3 MPa·√m.

Stefan Fünfschilling - One of the best experts on this subject based on the ideXlab platform.

  • Crack Tip toughness from vickers Crack Tip Opening displacements for materials with strongly rising r curves
    Journal of the American Ceramic Society, 2011
    Co-Authors: Stefan Fünfschilling, Theo Fett, Rainer Oberacker, Michael J. Hoffmann, Gerold A. Schneider, Paul F. Becher, Jamie J. Kruzic
    Abstract:

    Accurate measurements of the intrinsic Crack-Tip toughness, KI0, are essential to understanding the strength and toughness of bridging ceramics. Furthermore, even the most carefully made R-curve measurements cannot accurately assess this initial toughness point. In this manuscript, both rigorous and approximate methods are proposed for determining KI0 from Crack-Tip Opening displacement (COD) measurements on Vickers indent Cracks for materials with steeply rising R-curves. Such approaches are attractive because of the relative ease of producing indentation Cracks and analyzing the CODs; further, the latter method is of particular interest because it saves considerable computational effort. Both the advantages and limitations of the proposed methods are discussed. Finally, based on applying the above methods to three Si3N4 ceramics, it was concluded that there is a common Crack-Tip toughness of KI0≈2.2±0.3 MPa·√m.

  • Crack‐Tip Toughness from Vickers Crack‐Tip Opening Displacements for Materials with Strongly Rising R‐Curves
    Journal of the American Ceramic Society, 2011
    Co-Authors: Stefan Fünfschilling, Theo Fett, Rainer Oberacker, Michael J. Hoffmann, Gerold A. Schneider, Paul F. Becher, Jamie J. Kruzic
    Abstract:

    Accurate measurements of the intrinsic Crack-Tip toughness, KI0, are essential to understanding the strength and toughness of bridging ceramics. Furthermore, even the most carefully made R-curve measurements cannot accurately assess this initial toughness point. In this manuscript, both rigorous and approximate methods are proposed for determining KI0 from Crack-Tip Opening displacement (COD) measurements on Vickers indent Cracks for materials with steeply rising R-curves. Such approaches are attractive because of the relative ease of producing indentation Cracks and analyzing the CODs; further, the latter method is of particular interest because it saves considerable computational effort. Both the advantages and limitations of the proposed methods are discussed. Finally, based on applying the above methods to three Si3N4 ceramics, it was concluded that there is a common Crack-Tip toughness of KI0≈2.2±0.3 MPa·√m.

Mark A. James - One of the best experts on this subject based on the ideXlab platform.

  • A Relationship Between Constraint and the Critical Crack Tip Opening Angle
    2009
    Co-Authors: William M. Johnston, Mark A. James
    Abstract:

    Of the various approaches used to model and predict fracture, the Crack Tip Opening Angle (CTOA) fracture criterion has been successfully used for a wide range of two-dimensional thin-sheet and thin plate applications. As thicker structure is considered, modeling the full three-dimensional fracture process will become essential. This paper investigates relationships between the local CTOA evaluated along a three-dimensional Crack front and the corresponding local constraint. Previously reported tunneling Crack front shapes were measured during fracture by pausing each test and fatigue cycling the specimens to mark the Crack surface. Finite element analyses were run to model the tunneling shape during fracture, with the analysis loading conditions duplicating those tests. The results show an inverse relationship between the critical fracture value and constraint which is valid both before maximum load and after maximum load.

  • Development and application of a Crack Tip Opening displacement-based mixed mode fracture criterion
    International Journal of Solids and Structures, 2000
    Co-Authors: Michael A. Sutton, Xiaomin Deng, James C. Newman, Mark A. James
    Abstract:

    Abstract Consistent with experimental observations, a Crack Tip Opening displacement (CTOD)-based, mixed mode fracture criterion is developed for predicting the onset and direction of Crack growth. The criterion postulates that Crack growth occurs in either Mode I or Mode II direction, depending upon whether the maximum in either the Opening or the shear component of CTOD, measured at a specified distance behind the Crack Tip, attains a critical value. The proposed CTOD-based fracture criterion is implemented in two finite element codes to predict the stable tearing behavior of (a) a modified Arcan test specimen made of AL 2024-T3 and (b) a double cantilever beam (DCB) specimen made of AL 7050. Using the measured load-Crack extension data as input, results from simulations of stable Crack growth along experimentally measured Crack paths for the Arcan specimen demonstrate that the CTOD values obtained in the simulations are in excellent agreement with the proposed criterion. Then, using the CTOD criterion as input, simulations of the Arcan and DCB specimens demonstrate that the CTOD fracture criterion successfully predicts (a) load-Crack path data for both specimens, (b) load-Crack extension behavior for the Arcan specimen and (c) load-load point displacement data for the DCB specimen.

Paul F. Becher - One of the best experts on this subject based on the ideXlab platform.

  • Crack Tip toughness from vickers Crack Tip Opening displacements for materials with strongly rising r curves
    Journal of the American Ceramic Society, 2011
    Co-Authors: Stefan Fünfschilling, Theo Fett, Rainer Oberacker, Michael J. Hoffmann, Gerold A. Schneider, Paul F. Becher, Jamie J. Kruzic
    Abstract:

    Accurate measurements of the intrinsic Crack-Tip toughness, KI0, are essential to understanding the strength and toughness of bridging ceramics. Furthermore, even the most carefully made R-curve measurements cannot accurately assess this initial toughness point. In this manuscript, both rigorous and approximate methods are proposed for determining KI0 from Crack-Tip Opening displacement (COD) measurements on Vickers indent Cracks for materials with steeply rising R-curves. Such approaches are attractive because of the relative ease of producing indentation Cracks and analyzing the CODs; further, the latter method is of particular interest because it saves considerable computational effort. Both the advantages and limitations of the proposed methods are discussed. Finally, based on applying the above methods to three Si3N4 ceramics, it was concluded that there is a common Crack-Tip toughness of KI0≈2.2±0.3 MPa·√m.

  • Crack‐Tip Toughness from Vickers Crack‐Tip Opening Displacements for Materials with Strongly Rising R‐Curves
    Journal of the American Ceramic Society, 2011
    Co-Authors: Stefan Fünfschilling, Theo Fett, Rainer Oberacker, Michael J. Hoffmann, Gerold A. Schneider, Paul F. Becher, Jamie J. Kruzic
    Abstract:

    Accurate measurements of the intrinsic Crack-Tip toughness, KI0, are essential to understanding the strength and toughness of bridging ceramics. Furthermore, even the most carefully made R-curve measurements cannot accurately assess this initial toughness point. In this manuscript, both rigorous and approximate methods are proposed for determining KI0 from Crack-Tip Opening displacement (COD) measurements on Vickers indent Cracks for materials with steeply rising R-curves. Such approaches are attractive because of the relative ease of producing indentation Cracks and analyzing the CODs; further, the latter method is of particular interest because it saves considerable computational effort. Both the advantages and limitations of the proposed methods are discussed. Finally, based on applying the above methods to three Si3N4 ceramics, it was concluded that there is a common Crack-Tip toughness of KI0≈2.2±0.3 MPa·√m.

Gerold A. Schneider - One of the best experts on this subject based on the ideXlab platform.

  • Crack Tip toughness from vickers Crack Tip Opening displacements for materials with strongly rising r curves
    Journal of the American Ceramic Society, 2011
    Co-Authors: Stefan Fünfschilling, Theo Fett, Rainer Oberacker, Michael J. Hoffmann, Gerold A. Schneider, Paul F. Becher, Jamie J. Kruzic
    Abstract:

    Accurate measurements of the intrinsic Crack-Tip toughness, KI0, are essential to understanding the strength and toughness of bridging ceramics. Furthermore, even the most carefully made R-curve measurements cannot accurately assess this initial toughness point. In this manuscript, both rigorous and approximate methods are proposed for determining KI0 from Crack-Tip Opening displacement (COD) measurements on Vickers indent Cracks for materials with steeply rising R-curves. Such approaches are attractive because of the relative ease of producing indentation Cracks and analyzing the CODs; further, the latter method is of particular interest because it saves considerable computational effort. Both the advantages and limitations of the proposed methods are discussed. Finally, based on applying the above methods to three Si3N4 ceramics, it was concluded that there is a common Crack-Tip toughness of KI0≈2.2±0.3 MPa·√m.

  • Crack‐Tip Toughness from Vickers Crack‐Tip Opening Displacements for Materials with Strongly Rising R‐Curves
    Journal of the American Ceramic Society, 2011
    Co-Authors: Stefan Fünfschilling, Theo Fett, Rainer Oberacker, Michael J. Hoffmann, Gerold A. Schneider, Paul F. Becher, Jamie J. Kruzic
    Abstract:

    Accurate measurements of the intrinsic Crack-Tip toughness, KI0, are essential to understanding the strength and toughness of bridging ceramics. Furthermore, even the most carefully made R-curve measurements cannot accurately assess this initial toughness point. In this manuscript, both rigorous and approximate methods are proposed for determining KI0 from Crack-Tip Opening displacement (COD) measurements on Vickers indent Cracks for materials with steeply rising R-curves. Such approaches are attractive because of the relative ease of producing indentation Cracks and analyzing the CODs; further, the latter method is of particular interest because it saves considerable computational effort. Both the advantages and limitations of the proposed methods are discussed. Finally, based on applying the above methods to three Si3N4 ceramics, it was concluded that there is a common Crack-Tip toughness of KI0≈2.2±0.3 MPa·√m.