The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform

Ewald Werner - One of the best experts on this subject based on the ideXlab platform.

  • an unexpected feature of the Stress Strain Diagram of dual phase steel
    Computational Materials Science, 2002
    Co-Authors: U Liedl, S Traint, Ewald Werner
    Abstract:

    Abstract The microstructure of low alloyed ferritic–martensitic dual-phase steels as used for deep drawn parts in automotive applications consists of coarse grained hard martensitic inclusions embedded in a soft ferritic matrix. In tensile tests commercially produced dual-phase steels show an unexpected dependence of their initial yield behaviour on the content of martensite. The impact of the thermomechanical history on the mechanical properties of the material is demonstrated by means of a fully three-dimensional finite element analysis. A work-hardened ferritic skeleton formed during rapid cooling connects the martensitic inclusions and governs the initial stages of plastic deformation. The model correctly predicts both the experimentally observed dependence of the proof Stress on the amount of martensite and a lower initial slope of the Stress–Strain Diagram.

  • An unexpected feature of the Stress–Strain Diagram of dual-phase steel
    Computational Materials Science, 2002
    Co-Authors: U Liedl, S Traint, Ewald Werner
    Abstract:

    Abstract The microstructure of low alloyed ferritic–martensitic dual-phase steels as used for deep drawn parts in automotive applications consists of coarse grained hard martensitic inclusions embedded in a soft ferritic matrix. In tensile tests commercially produced dual-phase steels show an unexpected dependence of their initial yield behaviour on the content of martensite. The impact of the thermomechanical history on the mechanical properties of the material is demonstrated by means of a fully three-dimensional finite element analysis. A work-hardened ferritic skeleton formed during rapid cooling connects the martensitic inclusions and governs the initial stages of plastic deformation. The model correctly predicts both the experimentally observed dependence of the proof Stress on the amount of martensite and a lower initial slope of the Stress–Strain Diagram.

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

  • prediction of Stress Strain Diagram from forming load in stretch forming
    International Journal of Mechanical Sciences, 2012
    Co-Authors: Takashi Kuboki, Yingjun Jin, Makoto Murata
    Abstract:

    Abstract The objective of this research is to propose a prediction method of a Stress–Strain Diagram based on a stroke-load Diagram in stretch forming. In the proposed method, a set of characteristics in a Stress–Strain Diagram and the same number of characteristics in a stroke-load Diagram are chosen. A square matrix of influence coefficient is calculated on a master material using finite element analysis so that each element of the matrix is a partial differential of a stroke-load characteristic by a Stress–Strain characteristic. In the actual process of stretch forming, the differences of characteristics in a stroke-load Diagram are measured between the target and master materials. Based on the differences of characteristics of stroke-load, the characteristics of a Stress–Strain Diagram for the target material are calculated using the inverse matrix of the influence coefficient. In the present paper, the essential concept is introduced, and the error of prediction is estimated numerically, followed by experimental verification.

  • Prediction of Stress–Strain Diagram from forming load in stretch forming
    International Journal of Mechanical Sciences, 2012
    Co-Authors: Takashi Kuboki, Yingjun Jin, Makoto Murata
    Abstract:

    Abstract The objective of this research is to propose a prediction method of a Stress–Strain Diagram based on a stroke-load Diagram in stretch forming. In the proposed method, a set of characteristics in a Stress–Strain Diagram and the same number of characteristics in a stroke-load Diagram are chosen. A square matrix of influence coefficient is calculated on a master material using finite element analysis so that each element of the matrix is a partial differential of a stroke-load characteristic by a Stress–Strain characteristic. In the actual process of stretch forming, the differences of characteristics in a stroke-load Diagram are measured between the target and master materials. Based on the differences of characteristics of stroke-load, the characteristics of a Stress–Strain Diagram for the target material are calculated using the inverse matrix of the influence coefficient. In the present paper, the essential concept is introduced, and the error of prediction is estimated numerically, followed by experimental verification.

U Liedl - One of the best experts on this subject based on the ideXlab platform.

  • an unexpected feature of the Stress Strain Diagram of dual phase steel
    Computational Materials Science, 2002
    Co-Authors: U Liedl, S Traint, Ewald Werner
    Abstract:

    Abstract The microstructure of low alloyed ferritic–martensitic dual-phase steels as used for deep drawn parts in automotive applications consists of coarse grained hard martensitic inclusions embedded in a soft ferritic matrix. In tensile tests commercially produced dual-phase steels show an unexpected dependence of their initial yield behaviour on the content of martensite. The impact of the thermomechanical history on the mechanical properties of the material is demonstrated by means of a fully three-dimensional finite element analysis. A work-hardened ferritic skeleton formed during rapid cooling connects the martensitic inclusions and governs the initial stages of plastic deformation. The model correctly predicts both the experimentally observed dependence of the proof Stress on the amount of martensite and a lower initial slope of the Stress–Strain Diagram.

  • An unexpected feature of the Stress–Strain Diagram of dual-phase steel
    Computational Materials Science, 2002
    Co-Authors: U Liedl, S Traint, Ewald Werner
    Abstract:

    Abstract The microstructure of low alloyed ferritic–martensitic dual-phase steels as used for deep drawn parts in automotive applications consists of coarse grained hard martensitic inclusions embedded in a soft ferritic matrix. In tensile tests commercially produced dual-phase steels show an unexpected dependence of their initial yield behaviour on the content of martensite. The impact of the thermomechanical history on the mechanical properties of the material is demonstrated by means of a fully three-dimensional finite element analysis. A work-hardened ferritic skeleton formed during rapid cooling connects the martensitic inclusions and governs the initial stages of plastic deformation. The model correctly predicts both the experimentally observed dependence of the proof Stress on the amount of martensite and a lower initial slope of the Stress–Strain Diagram.

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

  • determination of biaxial Stress Strain Diagram for gas pressure superplastic forming
    Materials Science and Technology, 2006
    Co-Authors: A. Dutta, A. Kumar
    Abstract:

    AbstractThe success of a gas pressure superplastic forming operation depends on accurate formulation of a pressure–time Diagram which in turn needs an accurate Stress–Strain relationship evaluated preferably under multiaxial or biaxial conditions. The present analysis describes a technique of generating such curves from gas pressure cone forming tests and subsequent manipulation of the data. The method also includes an innovative technique of online monitoring of Strain during the forming process by measuring the volume of displaced air from the die during progress of forming.

  • Determination of biaxial Stress–Strain Diagram for gas pressure superplastic forming
    Materials Science and Technology, 2006
    Co-Authors: A. Dutta, A. Kumar
    Abstract:

    AbstractThe success of a gas pressure superplastic forming operation depends on accurate formulation of a pressure–time Diagram which in turn needs an accurate Stress–Strain relationship evaluated preferably under multiaxial or biaxial conditions. The present analysis describes a technique of generating such curves from gas pressure cone forming tests and subsequent manipulation of the data. The method also includes an innovative technique of online monitoring of Strain during the forming process by measuring the volume of displaced air from the die during progress of forming.

Tadashi Ohtani - One of the best experts on this subject based on the ideXlab platform.

  • the effects of mechanical parameters of the Stress Strain Diagram on wood abrasion
    Wear, 2008
    Co-Authors: Tadashi Ohtani
    Abstract:

    Abstract A wear test with abrasion was conducted for Hinoki cypress, Spruce and Agathis wood, and yield Stress parameters on Stress–Strain Diagrams were also extracted by mechanical tests. The relationship between the wear action and the mechanical parameters was investigated on the basis of the following extracted parameters of the yield Stress, σ ylim , σ y3% , σ y0.2% , and σ ymax : σ ylim is the proportional limit Stress, σ y3% is the Stress determined generally by the 3% reduced modulus method for wood, σ y0.2% is the 0.2% proof Stress adapted generally by other materials such as metal, and σ ymax is the maximum Stress. The correlation coefficient in the relationship between the wear rate in the rubbed axial section and the yield Stress parameter was higher in bending parallel to the sliding direction. The negative correlation was also higher in relation with the compression yield Stress perpendicular to the sliding surface at the increase stage of plastic Strain in the Stress–Strain Diagram. Considering that bending includes the compression element in wood deformation, it was concluded that the wood mechanical parameter σ ymax of compression yield Stress in maximum Stress point for evaluating abrasive wear is the most important information in the Stress–Strain Diagram.

  • The effects of mechanical parameters of the Stress–Strain Diagram on wood abrasion
    Wear, 2008
    Co-Authors: Tadashi Ohtani
    Abstract:

    Abstract A wear test with abrasion was conducted for Hinoki cypress, Spruce and Agathis wood, and yield Stress parameters on Stress–Strain Diagrams were also extracted by mechanical tests. The relationship between the wear action and the mechanical parameters was investigated on the basis of the following extracted parameters of the yield Stress, σ ylim , σ y3% , σ y0.2% , and σ ymax : σ ylim is the proportional limit Stress, σ y3% is the Stress determined generally by the 3% reduced modulus method for wood, σ y0.2% is the 0.2% proof Stress adapted generally by other materials such as metal, and σ ymax is the maximum Stress. The correlation coefficient in the relationship between the wear rate in the rubbed axial section and the yield Stress parameter was higher in bending parallel to the sliding direction. The negative correlation was also higher in relation with the compression yield Stress perpendicular to the sliding surface at the increase stage of plastic Strain in the Stress–Strain Diagram. Considering that bending includes the compression element in wood deformation, it was concluded that the wood mechanical parameter σ ymax of compression yield Stress in maximum Stress point for evaluating abrasive wear is the most important information in the Stress–Strain Diagram.