The Experts below are selected from a list of 156 Experts worldwide ranked by ideXlab platform

T Murata - One of the best experts on this subject based on the ideXlab platform.

  • a three segment anisomorphic Constant Life Diagram for the fatigue of symmetric angle ply carbon epoxy laminates at room temperature
    Composites Part A-applied Science and Manufacturing, 2010
    Co-Authors: Masamichi Kawai, T Murata
    Abstract:

    The anisomorphic Constant fatigue Life (CFL) Diagram approach that was developed in an earlier study is further tested for applicability to the matrix-dominated fatigue failure in symmetric angle-ply carbon/epoxy laminates. An extension of the CFL Diagram approach is also attempted to improve the accuracy of fatigue Life prediction. The original anisomorphic CFL Diagram approach can be used for approximately predicting the CFL Diagrams for the [±30]3S and [±45]3S laminates, while it fails to accurately predict the CFL Diagram for the [±60]3S laminate due to its significant local distortion. For accommodating the anisomorphic CFL Diagram approach to the local distortion in CFL curves due to a significant change in mean stress sensitivity in fatigue, a transitional segment is inserted between the tension–tension and compression–compression dominated segments. It is demonstrated that the three-segment anisomorphic CFL Diagram approach allows improved predictions of the CFL Diagrams and S–N relationships for the angle-ply laminates.

  • A three-segment anisomorphic Constant Life Diagram for the fatigue of symmetric angle-ply carbon/epoxy laminates at room temperature
    Composites Part A-applied Science and Manufacturing, 2010
    Co-Authors: Masamichi Kawai, T Murata
    Abstract:

    The anisomorphic Constant fatigue Life (CFL) Diagram approach that was developed in an earlier study is further tested for applicability to the matrix-dominated fatigue failure in symmetric angle-ply carbon/epoxy laminates. An extension of the CFL Diagram approach is also attempted to improve the accuracy of fatigue Life prediction. The original anisomorphic CFL Diagram approach can be used for approximately predicting the CFL Diagrams for the [±30]3S and [±45]3S laminates, while it fails to accurately predict the CFL Diagram for the [±60]3S laminate due to its significant local distortion. For accommodating the anisomorphic CFL Diagram approach to the local distortion in CFL curves due to a significant change in mean stress sensitivity in fatigue, a transitional segment is inserted between the tension–tension and compression–compression dominated segments. It is demonstrated that the three-segment anisomorphic CFL Diagram approach allows improved predictions of the CFL Diagrams and S–N relationships for the angle-ply laminates.

Masamichi Kawai - One of the best experts on this subject based on the ideXlab platform.

  • a failure mode based anisomorphic Constant Life Diagram for a unidirectional carbon epoxy laminate under off axis fatigue loading at room temperature
    Journal of Composite Materials, 2014
    Co-Authors: Masamichi Kawai, N Itoh
    Abstract:

    The off-axis Constant fatigue Life Diagrams for a unidirectional carbon/epoxy laminate in different fiber orientations are identified over the whole range of stress ratio. The experimental results show that the off-axis Constant fatigue Life Diagram plotted in the plane of alternating and mean stresses tends to shrink and incline to the left of the alternating stress axis more significantly as the off-axis angle of a specimen increases. The overall shapes of the off-axis Constant fatigue Life envelopes for different Constant values of Life are highly non-linear and asymmetric about the alternating stress axis, regardless of fiber orientation. These observations suggest that the sensitivity to mean stress in off-axis fatigue differs depending on the mode of fatigue loading, i.e. tension–tension, tension–compression, and compression–compression loading, and the difference is associated with the different modes of failure under different modes of fatigue loading. To deal with the off-axis fatigue strength of...

  • A failure-mode based anisomorphic Constant Life Diagram for a unidirectional carbon/epoxy laminate under off-axis fatigue loading at room temperature
    Journal of Composite Materials, 2013
    Co-Authors: Masamichi Kawai, N Itoh
    Abstract:

    The off-axis Constant fatigue Life Diagrams for a unidirectional carbon/epoxy laminate in different fiber orientations are identified over the whole range of stress ratio. The experimental results show that the off-axis Constant fatigue Life Diagram plotted in the plane of alternating and mean stresses tends to shrink and incline to the left of the alternating stress axis more significantly as the off-axis angle of a specimen increases. The overall shapes of the off-axis Constant fatigue Life envelopes for different Constant values of Life are highly non-linear and asymmetric about the alternating stress axis, regardless of fiber orientation. These observations suggest that the sensitivity to mean stress in off-axis fatigue differs depending on the mode of fatigue loading, i.e. tension–tension, tension–compression, and compression–compression loading, and the difference is associated with the different modes of failure under different modes of fatigue loading. To deal with the off-axis fatigue strength of...

  • a three segment anisomorphic Constant Life Diagram for the fatigue of symmetric angle ply carbon epoxy laminates at room temperature
    Composites Part A-applied Science and Manufacturing, 2010
    Co-Authors: Masamichi Kawai, T Murata
    Abstract:

    The anisomorphic Constant fatigue Life (CFL) Diagram approach that was developed in an earlier study is further tested for applicability to the matrix-dominated fatigue failure in symmetric angle-ply carbon/epoxy laminates. An extension of the CFL Diagram approach is also attempted to improve the accuracy of fatigue Life prediction. The original anisomorphic CFL Diagram approach can be used for approximately predicting the CFL Diagrams for the [±30]3S and [±45]3S laminates, while it fails to accurately predict the CFL Diagram for the [±60]3S laminate due to its significant local distortion. For accommodating the anisomorphic CFL Diagram approach to the local distortion in CFL curves due to a significant change in mean stress sensitivity in fatigue, a transitional segment is inserted between the tension–tension and compression–compression dominated segments. It is demonstrated that the three-segment anisomorphic CFL Diagram approach allows improved predictions of the CFL Diagrams and S–N relationships for the angle-ply laminates.

  • A three-segment anisomorphic Constant Life Diagram for the fatigue of symmetric angle-ply carbon/epoxy laminates at room temperature
    Composites Part A-applied Science and Manufacturing, 2010
    Co-Authors: Masamichi Kawai, T Murata
    Abstract:

    The anisomorphic Constant fatigue Life (CFL) Diagram approach that was developed in an earlier study is further tested for applicability to the matrix-dominated fatigue failure in symmetric angle-ply carbon/epoxy laminates. An extension of the CFL Diagram approach is also attempted to improve the accuracy of fatigue Life prediction. The original anisomorphic CFL Diagram approach can be used for approximately predicting the CFL Diagrams for the [±30]3S and [±45]3S laminates, while it fails to accurately predict the CFL Diagram for the [±60]3S laminate due to its significant local distortion. For accommodating the anisomorphic CFL Diagram approach to the local distortion in CFL curves due to a significant change in mean stress sensitivity in fatigue, a transitional segment is inserted between the tension–tension and compression–compression dominated segments. It is demonstrated that the three-segment anisomorphic CFL Diagram approach allows improved predictions of the CFL Diagrams and S–N relationships for the angle-ply laminates.

Thomas Keller - One of the best experts on this subject based on the ideXlab platform.

  • Experimental investigation and modeling of mean load effect on fatigue behavior of adhesively-bonded pultruded GFRP joints
    International Journal of Fatigue, 2012
    Co-Authors: Roohollah Sarfaraz, Anastasios P Vassilopoulos, Thomas Keller
    Abstract:

    The effect of mean load on the fatigue behavior of adhesively-bonded pultruded GFRP double-lap joints under Constant amplitude loading was experimentally investigated. The joints were examined under nine different stress ratios (R) representing pure tension, compression, and combined tension-compression fatigue loading. A transition of the failure mode, from tensile to compressive, was observed as the mean load decreased from positive to negative values. The slope of the S-N curves derived for R-ratios with positive or negative mean load consistently decreased with increasing mean load. The highest load amplitude corresponded to the R-ratio where the transition of the fatigue failure mode occurred (R = -2). The characteristics of the Constant Life Diagram developed for the examined bonded joints are thoroughly discussed. A phenomenological formulation was proposed and its accuracy evaluated by comparisons with the derived experimental data. The comparison of the new formulation with models commonly used for composite materials proved its higher accuracy that is achieved with less implementation effort. © 2012 Elsevier Ltd. All rights reserved.

  • piecewise non linear Constant Life Diagram formulation for frp composite materials
    International Journal of Fatigue, 2010
    Co-Authors: Anastasios P Vassilopoulos, Behzad D Manshadi, Thomas Keller
    Abstract:

    A new formulation for predicting an asymmetric, piecewise non-linear Constant Life Diagram (CLD) is introduced in this paper. The development of the new model is based on the representation of the fatigue data on the stress ratio (R)-stress amplitude (σa) plane instead of the conventional representation on the mean stress (σm)-stress amplitude (σa) plane. The advantage of this new CLD formulation is the accuracy of the derived CLD for a wide range of composite materials, even when only a limited amount of data is available. In addition it is not based on any assumptions and no complicated optimization processes have to be followed for the estimation of the model parameters. Although the idea of plotting Constant amplitude fatigue data in CLDs in order to account for the mean stress effect is not new, it is the first time that a CLD formulation is derived based on the interpretation of the available fatigue data on the R-σa plane. The validity of the proposed CLD formulation is evaluated by comparing predicted and experimental results for a wide range of composite materials. As proved herein, the proposed CLD formulation offers a better performance than most conventional CLD models found in the literature. © 2010 Elsevier Ltd. All rights reserved.

  • influence of the Constant Life Diagram formulation on the fatigue Life prediction of composite materials
    International Journal of Fatigue, 2010
    Co-Authors: Anastasios P Vassilopoulos, Behzad D Manshadi, Thomas Keller
    Abstract:

    The influence of the Constant Life Diagram (CLD) formulation on the fatigue Life prediction of composite materials was examined. Most commonly used and recently proposed CLDs applied on composite materials fatigue data are presented and their applicability on a number of data sets is demonstrated. Composite material fatigue data from a number of well documented databases were used. The influence of the selected CLD formulation on the fatigue Life prediction of composite material under spectrum loading is assessed by its ability to accurately predict unknown S–N curves for arbitrary loading. The results revealed that the simple piecewise linear formulation compares favorably to other more sophisticated and complicated schemes. For most of the cases studied, the S–N predictions based on the piecewise linear CLD are the most accurate ones.

  • pnl Constant Life Diagram formulation for frp composites materials
    Proceedings of the 14th European Conference on Composite Materials, 2010
    Co-Authors: Anastasios P Vassilopoulos, Behzad D Manshadi, Thomas Keller
    Abstract:

    Note: CD-ROM Reference EPFL-CONF-162214 Record created on 2011-01-11, modified on 2016-08-09

Anastasios P Vassilopoulos - One of the best experts on this subject based on the ideXlab platform.

  • Experimental investigation and modeling of mean load effect on fatigue behavior of adhesively-bonded pultruded GFRP joints
    International Journal of Fatigue, 2012
    Co-Authors: Roohollah Sarfaraz, Anastasios P Vassilopoulos, Thomas Keller
    Abstract:

    The effect of mean load on the fatigue behavior of adhesively-bonded pultruded GFRP double-lap joints under Constant amplitude loading was experimentally investigated. The joints were examined under nine different stress ratios (R) representing pure tension, compression, and combined tension-compression fatigue loading. A transition of the failure mode, from tensile to compressive, was observed as the mean load decreased from positive to negative values. The slope of the S-N curves derived for R-ratios with positive or negative mean load consistently decreased with increasing mean load. The highest load amplitude corresponded to the R-ratio where the transition of the fatigue failure mode occurred (R = -2). The characteristics of the Constant Life Diagram developed for the examined bonded joints are thoroughly discussed. A phenomenological formulation was proposed and its accuracy evaluated by comparisons with the derived experimental data. The comparison of the new formulation with models commonly used for composite materials proved its higher accuracy that is achieved with less implementation effort. © 2012 Elsevier Ltd. All rights reserved.

  • piecewise non linear Constant Life Diagram formulation for frp composite materials
    International Journal of Fatigue, 2010
    Co-Authors: Anastasios P Vassilopoulos, Behzad D Manshadi, Thomas Keller
    Abstract:

    A new formulation for predicting an asymmetric, piecewise non-linear Constant Life Diagram (CLD) is introduced in this paper. The development of the new model is based on the representation of the fatigue data on the stress ratio (R)-stress amplitude (σa) plane instead of the conventional representation on the mean stress (σm)-stress amplitude (σa) plane. The advantage of this new CLD formulation is the accuracy of the derived CLD for a wide range of composite materials, even when only a limited amount of data is available. In addition it is not based on any assumptions and no complicated optimization processes have to be followed for the estimation of the model parameters. Although the idea of plotting Constant amplitude fatigue data in CLDs in order to account for the mean stress effect is not new, it is the first time that a CLD formulation is derived based on the interpretation of the available fatigue data on the R-σa plane. The validity of the proposed CLD formulation is evaluated by comparing predicted and experimental results for a wide range of composite materials. As proved herein, the proposed CLD formulation offers a better performance than most conventional CLD models found in the literature. © 2010 Elsevier Ltd. All rights reserved.

  • influence of the Constant Life Diagram formulation on the fatigue Life prediction of composite materials
    International Journal of Fatigue, 2010
    Co-Authors: Anastasios P Vassilopoulos, Behzad D Manshadi, Thomas Keller
    Abstract:

    The influence of the Constant Life Diagram (CLD) formulation on the fatigue Life prediction of composite materials was examined. Most commonly used and recently proposed CLDs applied on composite materials fatigue data are presented and their applicability on a number of data sets is demonstrated. Composite material fatigue data from a number of well documented databases were used. The influence of the selected CLD formulation on the fatigue Life prediction of composite material under spectrum loading is assessed by its ability to accurately predict unknown S–N curves for arbitrary loading. The results revealed that the simple piecewise linear formulation compares favorably to other more sophisticated and complicated schemes. For most of the cases studied, the S–N predictions based on the piecewise linear CLD are the most accurate ones.

  • pnl Constant Life Diagram formulation for frp composites materials
    Proceedings of the 14th European Conference on Composite Materials, 2010
    Co-Authors: Anastasios P Vassilopoulos, Behzad D Manshadi, Thomas Keller
    Abstract:

    Note: CD-ROM Reference EPFL-CONF-162214 Record created on 2011-01-11, modified on 2016-08-09

N Itoh - One of the best experts on this subject based on the ideXlab platform.

  • a failure mode based anisomorphic Constant Life Diagram for a unidirectional carbon epoxy laminate under off axis fatigue loading at room temperature
    Journal of Composite Materials, 2014
    Co-Authors: Masamichi Kawai, N Itoh
    Abstract:

    The off-axis Constant fatigue Life Diagrams for a unidirectional carbon/epoxy laminate in different fiber orientations are identified over the whole range of stress ratio. The experimental results show that the off-axis Constant fatigue Life Diagram plotted in the plane of alternating and mean stresses tends to shrink and incline to the left of the alternating stress axis more significantly as the off-axis angle of a specimen increases. The overall shapes of the off-axis Constant fatigue Life envelopes for different Constant values of Life are highly non-linear and asymmetric about the alternating stress axis, regardless of fiber orientation. These observations suggest that the sensitivity to mean stress in off-axis fatigue differs depending on the mode of fatigue loading, i.e. tension–tension, tension–compression, and compression–compression loading, and the difference is associated with the different modes of failure under different modes of fatigue loading. To deal with the off-axis fatigue strength of...

  • A failure-mode based anisomorphic Constant Life Diagram for a unidirectional carbon/epoxy laminate under off-axis fatigue loading at room temperature
    Journal of Composite Materials, 2013
    Co-Authors: Masamichi Kawai, N Itoh
    Abstract:

    The off-axis Constant fatigue Life Diagrams for a unidirectional carbon/epoxy laminate in different fiber orientations are identified over the whole range of stress ratio. The experimental results show that the off-axis Constant fatigue Life Diagram plotted in the plane of alternating and mean stresses tends to shrink and incline to the left of the alternating stress axis more significantly as the off-axis angle of a specimen increases. The overall shapes of the off-axis Constant fatigue Life envelopes for different Constant values of Life are highly non-linear and asymmetric about the alternating stress axis, regardless of fiber orientation. These observations suggest that the sensitivity to mean stress in off-axis fatigue differs depending on the mode of fatigue loading, i.e. tension–tension, tension–compression, and compression–compression loading, and the difference is associated with the different modes of failure under different modes of fatigue loading. To deal with the off-axis fatigue strength of...