The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform

Sadao Hibi - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of orientation mechanism of crystallites in polyethylene cylindrical rod under tension-torsion Combined Stress
    Polymer, 2003
    Co-Authors: Takeshi Katagiri, Masanobu Sugimoto, Eiji Nakanishi, Sadao Hibi
    Abstract:

    Abstract A polyethylene cylindrical rod with lamellar structure is loaded with tension-torsion Combined Stress. The orientation behaviour of the crystallites is evaluated by an improved orientation distribution function. The function assumes affine deformation and that the orthogonal relation of the three crystallographic axes is maintained during deformation. The improved function is achieved by assuming that slippage deformation occurs in a crystallite block. For cases in which twist is strong and samples are highly deformed, the orientation behaviour is interpreted by taking into account the slippage deformation of the (110) plane. This, with the assumption of spiral orientation of the chain axis and rotation of the a- and b-axes around the c-axis, results in good agreement between calculation and experimental results.

  • Orientation behaviour of crystallites in cylindrical polyethylene rods under tension-torsion Combined Stress
    Polymer, 1993
    Co-Authors: Takeshi Katagiri, Masanobu Sugimoto, Eiji Nakanishi, Sadao Hibi
    Abstract:

    Abstract A tension-torsion Combined Stress was loaded onto cylindrical rods of polyethylene to investigate the deformation mechanism of the crystalline phase under non-uniform Stress. On applying the Combined Stress, a neck occurred at the centre of the sample and extended in the axial direction. After necking occurred, the twist deformation generated compressive Stress in the radial direction, which suppressed the formation of micro-voids. Wide-angle X-ray diffraction revealed the following facts. The c axis, i.e. the crystal molecular chain axis, deviates from the axial direction owing to the Combined loading of the tensile force and the shear force. The b axis, which is the long axis of the initial lamellae, orients selectively in the radial direction in the non-uniform Stress state in which the shear Stress increases in proportion to the distance from the centre of the cylindrical rod.

  • Yield Behavior Analysis of Polyetheretherketone (PEEK) under the Tension-torsion Combined Stress
    Seikei-Kakou, 1992
    Co-Authors: Takeshi Katagiri, Eiji Nakanishi, Sadao Hibi
    Abstract:

    The yield behavior of Polyetheretherketone (PEEK) under non-uniform Stress state was investigated using cylindrical rods loaded with tension-torsion Combined Stress. Along with the recording of tensile force and torsional torque, the change of sample shape was photographed at different stages of loading. The starting point of plastic deformation was discussed by according to the Nadai's equation. The load-unload cyclic tests under the Combined Stress were conducted in order to examine the generation of permanent strain. As a result, permanent strain in sample axis direction was generated after the maximum point in the torque-time curve, and this point is considered as the limit for use.

Takeshi Katagiri - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of orientation mechanism of crystallites in polyethylene cylindrical rod under tension-torsion Combined Stress
    Polymer, 2003
    Co-Authors: Takeshi Katagiri, Masanobu Sugimoto, Eiji Nakanishi, Sadao Hibi
    Abstract:

    Abstract A polyethylene cylindrical rod with lamellar structure is loaded with tension-torsion Combined Stress. The orientation behaviour of the crystallites is evaluated by an improved orientation distribution function. The function assumes affine deformation and that the orthogonal relation of the three crystallographic axes is maintained during deformation. The improved function is achieved by assuming that slippage deformation occurs in a crystallite block. For cases in which twist is strong and samples are highly deformed, the orientation behaviour is interpreted by taking into account the slippage deformation of the (110) plane. This, with the assumption of spiral orientation of the chain axis and rotation of the a- and b-axes around the c-axis, results in good agreement between calculation and experimental results.

  • Orientation behaviour of crystallites in cylindrical polyethylene rods under tension-torsion Combined Stress
    Polymer, 1993
    Co-Authors: Takeshi Katagiri, Masanobu Sugimoto, Eiji Nakanishi, Sadao Hibi
    Abstract:

    Abstract A tension-torsion Combined Stress was loaded onto cylindrical rods of polyethylene to investigate the deformation mechanism of the crystalline phase under non-uniform Stress. On applying the Combined Stress, a neck occurred at the centre of the sample and extended in the axial direction. After necking occurred, the twist deformation generated compressive Stress in the radial direction, which suppressed the formation of micro-voids. Wide-angle X-ray diffraction revealed the following facts. The c axis, i.e. the crystal molecular chain axis, deviates from the axial direction owing to the Combined loading of the tensile force and the shear force. The b axis, which is the long axis of the initial lamellae, orients selectively in the radial direction in the non-uniform Stress state in which the shear Stress increases in proportion to the distance from the centre of the cylindrical rod.

  • Yield Behavior Analysis of Polyetheretherketone (PEEK) under the Tension-torsion Combined Stress
    Seikei-Kakou, 1992
    Co-Authors: Takeshi Katagiri, Eiji Nakanishi, Sadao Hibi
    Abstract:

    The yield behavior of Polyetheretherketone (PEEK) under non-uniform Stress state was investigated using cylindrical rods loaded with tension-torsion Combined Stress. Along with the recording of tensile force and torsional torque, the change of sample shape was photographed at different stages of loading. The starting point of plastic deformation was discussed by according to the Nadai's equation. The load-unload cyclic tests under the Combined Stress were conducted in order to examine the generation of permanent strain. As a result, permanent strain in sample axis direction was generated after the maximum point in the torque-time curve, and this point is considered as the limit for use.

Shinji Ogihara - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of glass–epoxy interface strengths examined by cruciform specimen and single-fiber pull-out tests under Combined Stress state
    Composites Part A-applied Science and Manufacturing, 2012
    Co-Authors: Jun Koyanagi, Hayato Nakatani, Shinji Ogihara
    Abstract:

    Abstract A cruciform specimen test and a single-fiber pull-out test are used to examine two glass–epoxy interface-failure envelopes under a Combined Stress state. A single fiber embedded in various off-axis directions for the cruciform specimen test creates various Combined Stress states. Finite-element analysis considering an inelastic constitutive equation of matrix resin and thermal residual Stress is implemented for both tests. For the single-fiber pull-out test, a resin cone serving as the fiber entrance part, called the resin meniscus in this study, is modeled in finite-element analysis. This enables more precise calculation of interface Stress around the interface failure point than calculations not considering the resin meniscus. The interface failure strengths obtained using the cruciform specimen and single-fiber pull-out tests show good agreement for both interfaces.

  • comparison of glass epoxy interface strengths examined by cruciform specimen and single fiber pull out tests under Combined Stress state
    Composites Part A-applied Science and Manufacturing, 2012
    Co-Authors: Jun Koyanagi, Hayato Nakatani, Shinji Ogihara
    Abstract:

    Abstract A cruciform specimen test and a single-fiber pull-out test are used to examine two glass–epoxy interface-failure envelopes under a Combined Stress state. A single fiber embedded in various off-axis directions for the cruciform specimen test creates various Combined Stress states. Finite-element analysis considering an inelastic constitutive equation of matrix resin and thermal residual Stress is implemented for both tests. For the single-fiber pull-out test, a resin cone serving as the fiber entrance part, called the resin meniscus in this study, is modeled in finite-element analysis. This enables more precise calculation of interface Stress around the interface failure point than calculations not considering the resin meniscus. The interface failure strengths obtained using the cruciform specimen and single-fiber pull-out tests show good agreement for both interfaces.

  • investigation of Combined Stress state failure criterion for glass fiber epoxy interface by the cruciform specimen method
    Composites Science and Technology, 2010
    Co-Authors: Shinji Ogihara, Jun Koyanagi
    Abstract:

    The interfacial failure criterion under Combined Stress state in a glass fiber/epoxy composite is investigated by the cruciform specimen method. Experiments were conducted by using specimens with a fiber whose angle from the loading direction is varied in order to make various Stress state of normal and shear at the interface. Finite element analysis is performed to calculate the interfacial Stress distribution. By combining the experimental measurement of the specimen Stress at the interfacial debonding initiation and the finite element Stress analysis, it is possible to obtain the interfacial Stress state at interfacial failure. A method to determine the interfacial failure criterion and the interfacial failure initiation location simultaneously is proposed in the present study. We conclude the value of the interfacial shear strength is higher than that of the interfacial normal strength for the material system used in the present study.

Eiji Nakanishi - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of orientation mechanism of crystallites in polyethylene cylindrical rod under tension-torsion Combined Stress
    Polymer, 2003
    Co-Authors: Takeshi Katagiri, Masanobu Sugimoto, Eiji Nakanishi, Sadao Hibi
    Abstract:

    Abstract A polyethylene cylindrical rod with lamellar structure is loaded with tension-torsion Combined Stress. The orientation behaviour of the crystallites is evaluated by an improved orientation distribution function. The function assumes affine deformation and that the orthogonal relation of the three crystallographic axes is maintained during deformation. The improved function is achieved by assuming that slippage deformation occurs in a crystallite block. For cases in which twist is strong and samples are highly deformed, the orientation behaviour is interpreted by taking into account the slippage deformation of the (110) plane. This, with the assumption of spiral orientation of the chain axis and rotation of the a- and b-axes around the c-axis, results in good agreement between calculation and experimental results.

  • Orientation behaviour of crystallites in cylindrical polyethylene rods under tension-torsion Combined Stress
    Polymer, 1993
    Co-Authors: Takeshi Katagiri, Masanobu Sugimoto, Eiji Nakanishi, Sadao Hibi
    Abstract:

    Abstract A tension-torsion Combined Stress was loaded onto cylindrical rods of polyethylene to investigate the deformation mechanism of the crystalline phase under non-uniform Stress. On applying the Combined Stress, a neck occurred at the centre of the sample and extended in the axial direction. After necking occurred, the twist deformation generated compressive Stress in the radial direction, which suppressed the formation of micro-voids. Wide-angle X-ray diffraction revealed the following facts. The c axis, i.e. the crystal molecular chain axis, deviates from the axial direction owing to the Combined loading of the tensile force and the shear force. The b axis, which is the long axis of the initial lamellae, orients selectively in the radial direction in the non-uniform Stress state in which the shear Stress increases in proportion to the distance from the centre of the cylindrical rod.

  • Yield Behavior Analysis of Polyetheretherketone (PEEK) under the Tension-torsion Combined Stress
    Seikei-Kakou, 1992
    Co-Authors: Takeshi Katagiri, Eiji Nakanishi, Sadao Hibi
    Abstract:

    The yield behavior of Polyetheretherketone (PEEK) under non-uniform Stress state was investigated using cylindrical rods loaded with tension-torsion Combined Stress. Along with the recording of tensile force and torsional torque, the change of sample shape was photographed at different stages of loading. The starting point of plastic deformation was discussed by according to the Nadai's equation. The load-unload cyclic tests under the Combined Stress were conducted in order to examine the generation of permanent strain. As a result, permanent strain in sample axis direction was generated after the maximum point in the torque-time curve, and this point is considered as the limit for use.

Jun Koyanagi - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of glass–epoxy interface strengths examined by cruciform specimen and single-fiber pull-out tests under Combined Stress state
    Composites Part A-applied Science and Manufacturing, 2012
    Co-Authors: Jun Koyanagi, Hayato Nakatani, Shinji Ogihara
    Abstract:

    Abstract A cruciform specimen test and a single-fiber pull-out test are used to examine two glass–epoxy interface-failure envelopes under a Combined Stress state. A single fiber embedded in various off-axis directions for the cruciform specimen test creates various Combined Stress states. Finite-element analysis considering an inelastic constitutive equation of matrix resin and thermal residual Stress is implemented for both tests. For the single-fiber pull-out test, a resin cone serving as the fiber entrance part, called the resin meniscus in this study, is modeled in finite-element analysis. This enables more precise calculation of interface Stress around the interface failure point than calculations not considering the resin meniscus. The interface failure strengths obtained using the cruciform specimen and single-fiber pull-out tests show good agreement for both interfaces.

  • comparison of glass epoxy interface strengths examined by cruciform specimen and single fiber pull out tests under Combined Stress state
    Composites Part A-applied Science and Manufacturing, 2012
    Co-Authors: Jun Koyanagi, Hayato Nakatani, Shinji Ogihara
    Abstract:

    Abstract A cruciform specimen test and a single-fiber pull-out test are used to examine two glass–epoxy interface-failure envelopes under a Combined Stress state. A single fiber embedded in various off-axis directions for the cruciform specimen test creates various Combined Stress states. Finite-element analysis considering an inelastic constitutive equation of matrix resin and thermal residual Stress is implemented for both tests. For the single-fiber pull-out test, a resin cone serving as the fiber entrance part, called the resin meniscus in this study, is modeled in finite-element analysis. This enables more precise calculation of interface Stress around the interface failure point than calculations not considering the resin meniscus. The interface failure strengths obtained using the cruciform specimen and single-fiber pull-out tests show good agreement for both interfaces.

  • investigation of Combined Stress state failure criterion for glass fiber epoxy interface by the cruciform specimen method
    Composites Science and Technology, 2010
    Co-Authors: Shinji Ogihara, Jun Koyanagi
    Abstract:

    The interfacial failure criterion under Combined Stress state in a glass fiber/epoxy composite is investigated by the cruciform specimen method. Experiments were conducted by using specimens with a fiber whose angle from the loading direction is varied in order to make various Stress state of normal and shear at the interface. Finite element analysis is performed to calculate the interfacial Stress distribution. By combining the experimental measurement of the specimen Stress at the interfacial debonding initiation and the finite element Stress analysis, it is possible to obtain the interfacial Stress state at interfacial failure. A method to determine the interfacial failure criterion and the interfacial failure initiation location simultaneously is proposed in the present study. We conclude the value of the interfacial shear strength is higher than that of the interfacial normal strength for the material system used in the present study.