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L. Dietrich - One of the best experts on this subject based on the ideXlab platform.

  • Accumulation of Damage in A336 GR5 Structural Steel Subject to Complex Stress Loading
    Strain, 2011
    Co-Authors: L. Dietrich, Grzegorz Socha
    Abstract:

    :  Changes in the mechanical characteristics of the structural steel because of fatigue damage accumulation are investigated in this article. Cyclic loading was performed in a Complex Stress state. Tubular specimens were loaded by axial force and torque, with loading performed along proportional and non-proportional paths in the strain space. Material characteristics in the form of the Stress–strain curve and yield surface were determined in the ‘as received’ state and after cyclic loading. It was found that accumulation of the fatigue damage because of cyclic loading in a Complex Stress state along proportional and non-proportional paths in the strain space is manifested by the increase in inelastic response. The rate of damage was found to be higher for non-proportional (circular) loading paths than that for proportional loading with the same strain amplitude.

  • Analysis of a thermally induced phase transformation strain state for the TiNi shape memory alloy under a Complex Stress state
    The Journal of Strain Analysis for Engineering Design, 2002
    Co-Authors: G. Socha, L. Dietrich
    Abstract:

    In the paper an analysis of isostatic testing results for the Ti-51.0 at. % Ni shape memory alloy are presented. Tests were performed in a Complex Stress state, the tubular specimen being loaded by a combination of axial load and torque. After achieving a specified level of the load under Complex and various Stress states, a thermal cycle was started. During the test, the temperature-induced phase transformations were observed as variations in the transformation strain tensor components. These strain components were measured with the use of resistive strain gauges, digitally recorded and processed to extract pure phase transformation strains. For selected Complex Stress states, the transformation strain tensor components, principal transformation strains and characteristic temperatures of the phase transformations were found. On the basis of the experimental data, basic relations between characteristic parameters of an imposed Stress state and the temperature-induced phase transformation strain state were determined.

  • Experimental methodology for TiNi shape memory alloy testing under Complex Stress state
    Archives of Mechanics, 1999
    Co-Authors: B. Raniecki, L. Dietrich, Zbigniew L. Kowalewski, G. Socha, Shuichi Miyazaki, K. Tanaka, Andrzej Ziolkowski
    Abstract:

    THE EXPERIMENTAL METHOD and preliminary results of multiaxial proportional loadings at a range of different temperatures are discussed for the TiNi shape memory alloy. The results are limited to the R-phase reorientation and transformation pseudoelasticity of the material tested at the selected constant temperatures. The main objective of the paper is to develop experimental knowledge of the shape memory alloy properties under Complex Stress states which would allow better understanding of the material behaviour and create a basis for theoretical modelling.

Shen Kai-zhi - One of the best experts on this subject based on the ideXlab platform.

  • Properties and Morphology of Biaxial Self-Reinforced HDPE Pipes Under Complex Stress Field
    The Plastics, 2009
    Co-Authors: Shen Kai-zhi
    Abstract:

    Using self-made shearing-drawing biaxial Complex Stress field die,three types of biaxially self-reinforced high density polyethylene(HDPE) pipe were extruded under traditional process conditions.Compared to regularly extruded pipes,the circumferential tensile strength of three types of HDPE(2480,HD4801EX and 5421B) was increased by 24.8 %,41.7 % and 21.5 %,respectively when the rotational speed of shear casing was 20 r/min,while the axial tensile strength increased by 12.7 %,16.8 % and 10.4 % respectively.The samples of HDPE(2480) were characterized by SEM,WAXD and DSC.It was found that the microstructure of self-reinforced pipes was still spherocrystal,but crystallite sizes decreased,melting points drifted to high temperature and the degree of crystallinity increased under Complex Stress field.Meanwhile,the diffraction intensity of biaxial self-reinforced pipe increased and the molecular chain orientation increased too.

  • Study of Biaxially Self-reinforced Polypropylene Pipes under Complex Stress Field
    China Plastics, 2009
    Co-Authors: Shen Kai-zhi
    Abstract:

    Polypropylene pipes were extruded using a home-made shearing/drawing biaxial Complex Stress field die.Compared to regularly extruded pipes,the circumferential and axial tensile strengths of the pipes were 21.4 % and 21.1 % higher,respectively,when the shear casing rotational speed was 10 r/min and the shear casing temperature was 190 ℃.The pipe samples were characterized by SEM,WAXD and DSC.It was found that the spherulites of the pipe was not obvious and arranged more regularly.The melting points drift to higher temperature and the degree of crystallinity increased.XRD showed the orientation in both directions of the pipes was higher than regular ones.

  • Research on Solid State Extrusion of HDPE in Complex Stress Field
    China Plastics, 2003
    Co-Authors: Shen Kai-zhi
    Abstract:

    Biaxially self-reinforced HDPE sheet was prepared by the die with Complex Stress field on the solid state.The results showed that the longitudinal tensile strength and transverse tensile strength were increased sharply.Highly tropism,orderly arranged micro-fiber structure was produced and these micro-fiber stucture endowed the material with extremely high strength.

  • Research on Critical State Extrusion of PE in Complex Stress Field
    China Plastics, 2003
    Co-Authors: Shen Kai-zhi
    Abstract:

    Biaxially self-reinforced PE sheet was prepared by the die with Complex Stress field in critical state.The results showed that the longitudinal tensile strength and transverse tensile strength were increased sharply.Vica soft points of PE self-reinforced sheets had been improved to 21℃.Shish kebab structure were produced and these structure endowed the material with extreme strength.

  • Study on Preparation of Biaxial Stretching Self-reinforced HDPE Sheets at Complex Stress Field
    China Plastics Industry, 2003
    Co-Authors: Shen Kai-zhi
    Abstract:

    Biaxial Stretching self-reinforced HDPE sheets were prepared by using the die with Complex Stress field. The results showed that the longitudinal and transverse direction tensile strength of the prepared sheets had all been improved obviously and the morphology of the self-reinforced sheets were shish-kebab structure. Owing to the formation of this shish-kebab structure, the strength of the sheets were improved. The relationships between the microstructures and properties of the sheets were revealed.

Andrzej Ziolkowski - One of the best experts on this subject based on the ideXlab platform.

  • Experimental methodology for TiNi shape memory alloy testing under Complex Stress state
    Archives of Mechanics, 1999
    Co-Authors: B. Raniecki, L. Dietrich, Zbigniew L. Kowalewski, G. Socha, Shuichi Miyazaki, K. Tanaka, Andrzej Ziolkowski
    Abstract:

    THE EXPERIMENTAL METHOD and preliminary results of multiaxial proportional loadings at a range of different temperatures are discussed for the TiNi shape memory alloy. The results are limited to the R-phase reorientation and transformation pseudoelasticity of the material tested at the selected constant temperatures. The main objective of the paper is to develop experimental knowledge of the shape memory alloy properties under Complex Stress states which would allow better understanding of the material behaviour and create a basis for theoretical modelling.

G. Socha - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of a thermally induced phase transformation strain state for the TiNi shape memory alloy under a Complex Stress state
    The Journal of Strain Analysis for Engineering Design, 2002
    Co-Authors: G. Socha, L. Dietrich
    Abstract:

    In the paper an analysis of isostatic testing results for the Ti-51.0 at. % Ni shape memory alloy are presented. Tests were performed in a Complex Stress state, the tubular specimen being loaded by a combination of axial load and torque. After achieving a specified level of the load under Complex and various Stress states, a thermal cycle was started. During the test, the temperature-induced phase transformations were observed as variations in the transformation strain tensor components. These strain components were measured with the use of resistive strain gauges, digitally recorded and processed to extract pure phase transformation strains. For selected Complex Stress states, the transformation strain tensor components, principal transformation strains and characteristic temperatures of the phase transformations were found. On the basis of the experimental data, basic relations between characteristic parameters of an imposed Stress state and the temperature-induced phase transformation strain state were determined.

  • Experimental methodology for TiNi shape memory alloy testing under Complex Stress state
    Archives of Mechanics, 1999
    Co-Authors: B. Raniecki, L. Dietrich, Zbigniew L. Kowalewski, G. Socha, Shuichi Miyazaki, K. Tanaka, Andrzej Ziolkowski
    Abstract:

    THE EXPERIMENTAL METHOD and preliminary results of multiaxial proportional loadings at a range of different temperatures are discussed for the TiNi shape memory alloy. The results are limited to the R-phase reorientation and transformation pseudoelasticity of the material tested at the selected constant temperatures. The main objective of the paper is to develop experimental knowledge of the shape memory alloy properties under Complex Stress states which would allow better understanding of the material behaviour and create a basis for theoretical modelling.

B. Raniecki - One of the best experts on this subject based on the ideXlab platform.

  • Experimental methodology for TiNi shape memory alloy testing under Complex Stress state
    Archives of Mechanics, 1999
    Co-Authors: B. Raniecki, L. Dietrich, Zbigniew L. Kowalewski, G. Socha, Shuichi Miyazaki, K. Tanaka, Andrzej Ziolkowski
    Abstract:

    THE EXPERIMENTAL METHOD and preliminary results of multiaxial proportional loadings at a range of different temperatures are discussed for the TiNi shape memory alloy. The results are limited to the R-phase reorientation and transformation pseudoelasticity of the material tested at the selected constant temperatures. The main objective of the paper is to develop experimental knowledge of the shape memory alloy properties under Complex Stress states which would allow better understanding of the material behaviour and create a basis for theoretical modelling.