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Michael R Wisnom - One of the best experts on this subject based on the ideXlab platform.

  • parametric study of failure mechanisms and optimal configurations of pseudo ductile thin ply ud hybrid composites
    Composites Part A-applied Science and Manufacturing, 2015
    Co-Authors: Meisam Jalalvand, Gergely Czel, Michael R Wisnom
    Abstract:

    Abstract The effect of different parameters on the gradual failure and pseudo-ductility of thin UD hybrids is studied using an analytical method developed recently. Damage mode maps are proposed to show the effect of different geometric parameters for a specific Material Combination. This type of map is a novel and efficient method to find the optimum configuration of UD hybrids and also indicates the importance of thin layers to achieve the optimum geometric parameters in practice. The Material parametric study reveals that there is always a trade-off between the “yield stress” and the amount of pseudo-ductility; higher yield stresses leads to lower pseudo-ductility and vice versa. However, application of high-stiffness fibres with high strengths as the low strain Material can provide both better pseudo-ductility and yield stress.

  • parametric study of failure mechanisms and optimal configurations of pseudo ductile thin ply ud hybrid composites part a applied science and manufacturing
    Composites, 2015
    Co-Authors: Meisam Jalalvand, Gergely Czel, Michael R Wisnom
    Abstract:

    The effect of different parameters on the gradual failure and pseudo-ductility of thin UD hybrids is studied using an analytical method developed recently. Damage mode maps are proposed to show the effect of different geometric parameters for a specific Material Combination. This type of map is a novel and efficient method to find the optimum configuration of UD hybrids and also indicates the importance of thin layers to achieve the optimum geometric parameters in practice. The Material parametric study reveals that there is always a trade-off between the “yield stress” and the amount of pseudo-ductility; higher yield stresses leads to lower pseudo-ductility and vice versa. However, application of high-stiffness fibres with high strengths as the low strain Material can provide both better pseudo-ductility and yield stress.

Naoaki Noda - One of the best experts on this subject based on the ideXlab platform.

  • effect of arbitrary bi Material Combination and bending loading conditions on stress intensity factors of an edge interface crack
    International Journal of Structural Integrity, 2012
    Co-Authors: Kazuhiro Oda, Naoaki Noda, Xin Lan, Kengo Michinaka
    Abstract:

    Purpose – The purpose of this paper is to compute the stress intensity factors (SIFs) of single edge interface crack for arbitrary Material Combinations and various relative crack lengths, and compare with those for the bonded plates subjected to tensile loading conditions. It aims to discuss the results of the shallow edge interface crack on the basis of the singular stress near the free‐edge corner without the crack.Design/methodology/approach – In this study, the SIFs of interface crack in dissimilar bonded plates subjected to bending loading conditions are analyzed by the finite element method and a post‐processing technique. The use of post‐processing technique of extrapolation reduces the computational cost and improves the accuracy of the obtained result.Findings – The empirical expressions are proposed for evaluating the SIFs of arbitrary Material Combinations.Originality/value – Empirical functions can be used to obtain the SIFs for arbitrary Material Combinations for the bending loading conditio...

  • single and double edge interface crack solutions for arbitrary forms of Material Combination
    Acta Mechanica Solida Sinica, 2012
    Co-Authors: Xin Lan, Naoaki Noda, Yu Zhang, Kengo Michinaka
    Abstract:

    In this paper interfacial edge crack problems are considered by the application of the finite element method. The stress intensity factors are accurately determined from the ratio of crack-tip-stress value between the target given unknown and reference problems. The reference problem is chosen to produce the singular stress fields proportional to those of the given unknown problem. Here the original proportional method is improved through utilizing very refined meshes and post-processing technique of linear extrapolation. The results for a double-edge interface crack in a bonded strip are newly obtained and compared with those of a single-edge interface crack for different forms of Combination of Material. It is found that the stress intensity factors should be compared in the three different zones of relative crack lengths. Different from the case of a cracked homogeneous strip, the results for the double edge interface cracks are found to possibly be bigger than those for a single edge interface crack under the same relative crack length.

  • stress intensity factors for an edge interface crack in a bonded semi infinite plate for arbitrary Material Combination
    International Journal of Solids and Structures, 2012
    Co-Authors: Naoaki Noda
    Abstract:

    Abstract Although a lot of interface crack problems were previously treated, few solutions are available under arbitrary crack lengths and Material Combinations. In this paper the stress intensity factors of an edge interface crack in a bonded strip are considered under tension with varying the crack length and Material Combinations systematically. Then, the limiting solutions are provided for an edge interface crack in a bonded semi-infinite plate under arbitrary Material Combinations. In order to calculate the stress intensity factors accurately, exact solutions in an infinite bonded plate are also considered to produce proportional singular stress fields in the analysis of FEM by superposing specific tensile and shear stresses at infinity. The details of this new numerical solution are described with clarifying the effect of the element size on the stress intensity factor. It is found that for the edge interface crack the normalized stress intensity factors are not always finite depending upon Dunders’ parameters. This behavior can be explained from the condition of the singular stress at the end of bonded strip. Convenient formulas are also given by fitting the computed results.

  • stress intensity factor of an interface crack in a bonded plate under uni axial tension
    Journal of Solid Mechanics and Materials Engineering, 2010
    Co-Authors: Naoaki Noda, Yu Zhang, Yasushi Takase
    Abstract:

    Although a lot of interface crack problems were previously treated, few solutions are available under arbitrary Material Combination. This paper deals with a central interface crack in a bonded infinite plate and finite plate. Then, the effects of Material Combination on the stress intensity factors are discussed. A useful method to calculate the stress intensity factor of interface crack is presented with focusing on the stress at the crack tip calculated by the finite element method. For the central interface crack, it is found that the results of bonded infinite plate under remote uni-axial tension are always depending on the Dunders’ parameters α, β and different from the well-known solution of the central interface crack under internal pressure that is only depending on β . Besides, it is shown that the stress intensity factor of bonded infinite plate can be estimated from the stress of crack tip in the bonded plate when there is no crack. It is also found that dimensionless stress intensity factor FI 0, FI >1 when (α+2β)(α-2β) <0, and FI =1 when (α+2β)(α-2β) =0.

Meisam Jalalvand - One of the best experts on this subject based on the ideXlab platform.

  • parametric study of failure mechanisms and optimal configurations of pseudo ductile thin ply ud hybrid composites
    Composites Part A-applied Science and Manufacturing, 2015
    Co-Authors: Meisam Jalalvand, Gergely Czel, Michael R Wisnom
    Abstract:

    Abstract The effect of different parameters on the gradual failure and pseudo-ductility of thin UD hybrids is studied using an analytical method developed recently. Damage mode maps are proposed to show the effect of different geometric parameters for a specific Material Combination. This type of map is a novel and efficient method to find the optimum configuration of UD hybrids and also indicates the importance of thin layers to achieve the optimum geometric parameters in practice. The Material parametric study reveals that there is always a trade-off between the “yield stress” and the amount of pseudo-ductility; higher yield stresses leads to lower pseudo-ductility and vice versa. However, application of high-stiffness fibres with high strengths as the low strain Material can provide both better pseudo-ductility and yield stress.

  • parametric study of failure mechanisms and optimal configurations of pseudo ductile thin ply ud hybrid composites part a applied science and manufacturing
    Composites, 2015
    Co-Authors: Meisam Jalalvand, Gergely Czel, Michael R Wisnom
    Abstract:

    The effect of different parameters on the gradual failure and pseudo-ductility of thin UD hybrids is studied using an analytical method developed recently. Damage mode maps are proposed to show the effect of different geometric parameters for a specific Material Combination. This type of map is a novel and efficient method to find the optimum configuration of UD hybrids and also indicates the importance of thin layers to achieve the optimum geometric parameters in practice. The Material parametric study reveals that there is always a trade-off between the “yield stress” and the amount of pseudo-ductility; higher yield stresses leads to lower pseudo-ductility and vice versa. However, application of high-stiffness fibres with high strengths as the low strain Material can provide both better pseudo-ductility and yield stress.

Gergely Czel - One of the best experts on this subject based on the ideXlab platform.

  • parametric study of failure mechanisms and optimal configurations of pseudo ductile thin ply ud hybrid composites
    Composites Part A-applied Science and Manufacturing, 2015
    Co-Authors: Meisam Jalalvand, Gergely Czel, Michael R Wisnom
    Abstract:

    Abstract The effect of different parameters on the gradual failure and pseudo-ductility of thin UD hybrids is studied using an analytical method developed recently. Damage mode maps are proposed to show the effect of different geometric parameters for a specific Material Combination. This type of map is a novel and efficient method to find the optimum configuration of UD hybrids and also indicates the importance of thin layers to achieve the optimum geometric parameters in practice. The Material parametric study reveals that there is always a trade-off between the “yield stress” and the amount of pseudo-ductility; higher yield stresses leads to lower pseudo-ductility and vice versa. However, application of high-stiffness fibres with high strengths as the low strain Material can provide both better pseudo-ductility and yield stress.

  • parametric study of failure mechanisms and optimal configurations of pseudo ductile thin ply ud hybrid composites part a applied science and manufacturing
    Composites, 2015
    Co-Authors: Meisam Jalalvand, Gergely Czel, Michael R Wisnom
    Abstract:

    The effect of different parameters on the gradual failure and pseudo-ductility of thin UD hybrids is studied using an analytical method developed recently. Damage mode maps are proposed to show the effect of different geometric parameters for a specific Material Combination. This type of map is a novel and efficient method to find the optimum configuration of UD hybrids and also indicates the importance of thin layers to achieve the optimum geometric parameters in practice. The Material parametric study reveals that there is always a trade-off between the “yield stress” and the amount of pseudo-ductility; higher yield stresses leads to lower pseudo-ductility and vice versa. However, application of high-stiffness fibres with high strengths as the low strain Material can provide both better pseudo-ductility and yield stress.

R. Scott - One of the best experts on this subject based on the ideXlab platform.

  • The Effects of Material Combination and Lubricant on the Friction of Total Hip Prostheses
    Wear, 2000
    Co-Authors: S C Scholes, Anthony Unsworth, R.m. Hall, R. Scott
    Abstract:

    Polymeric wear debris produced by articulation of the femoral head against the ultra-high-molecular-weight polyethylene (UHMWPE) socket of a total hip replacement has been implicated as the main cause of osteolysis and subsequent failure of these implants. Potential solutions to this problem are to employ hard-bearing surface Combinations such as metal-on-metal or ceramic-on-ceramic prostheses. The aim of this study was to investigate the difference in lubrication modes and friction of a range of Material Combinations using synthetic and biological fluids as the lubricants. The experimental results were compared with theoretical predictions of film thicknesses and lubrication modes. A strong correlation was observed between experiment and theory when employing carboxy methyl cellulose fluids as the lubricant. Under these conditions, the ceramic-on-ceramic joints showed full fluid film lubrication while the metal-on-metal and metal-on-plastic prostheses operated under a mixed lubrication regime. With bovine serum as the lubricant in the all ceramic joint however, the full fluid film lubrication was inhibited due to adsorbed proteins. In the metal-on-metal joints, this adsorbed protein layer acted to reduce the friction while in the ceramic coupling the friction was increased. The use of bovine serum as the lubricant also significantly increased the friction in the metal-on-plastic joint. Therefore, the simple calculations using non-biological lubricants should not be relied upon in the design of orthopaedic bearing surfaces.

  • The Effects of Material Combination and Lubricant on the Friction of Total Hip Prostheses
    Wear, 2000
    Co-Authors: S C Scholes, Anthony Unsworth, R.m. Hall, R. Scott
    Abstract:

    Polymeric wear debris produced by articulation of the femoral head against the ultra-high-molecular-weight polyethylene (UHMWPE) socket of a total hip replacement has been implicated as the main cause of osteolysis and subsequent failure of these implants. Potential solutions to this problem are to employ hard-bearing surface Combinations such as metal-on-metal or ceramic-on-ceramic prostheses. The aim of this study was to investigate the difference in lubrication modes and friction of a range of Material Combinations using synthetic and biological fluids as the lubricants. The experimental results were compared with theoretical predictions of film thicknesses and lubrication modes. A strong correlation was observed between experiment and theory when employing carboxy methyl cellulose fluids as the lubricant. Under these conditions, the ceramic-on-ceramic joints showed full fluid film lubrication while the metal-on-metal and metal-on-plastic prostheses operated under a mixed lubrication regime. With bovine serum as the lubricant in the all ceramic joint however, the full fluid film lubrication was inhibited due to adsorbed proteins. In the metal-on-metal joints, this adsorbed protein layer acted to reduce the friction while in the ceramic coupling the friction was increased. The use of bovine serum as the lubricant also significantly increased the friction in the metal-on-plastic joint. Therefore, the simple calculations using non-biological lubricants should not be relied upon in the design of orthopaedic bearing surfaces.

  • The Effects of Material Combination and Lubricant on the Friction of Total Hip Prostheses
    1998
    Co-Authors: S C Scholes, Anthony Unsworth, R.m. Hall, R. Scott
    Abstract:

    Polymeric wear debris produced by articulation of the femoral head against the ultra-high-molecular-weight polyethylene socket of a total hip replacement has been implicated as the main cause of osteolysis and subsequent failure of these implants. Potential solutions to this problem are to employ hard bearing surface Combinations such as metal-on-metal or ceramic-on-ceramic prostheses. The aim of this study was to investigate the difference in lubrication modes and friction of a range of Material Combinations using synthetic and biological fluids as the lubricants. The experimental results were compared with theoretical predictions of film thicknesses and lubrication modes. A strong correlation was observed between experiment and theory when employing CMC fluids as the lubricant. Under these conditions the ceramic-on-ceramic joints showed full fluid film lubrication while the metal-on-metal and metal-on-plastic prostheses operated under a mixed lubrication regime. With bovine serum as the lubricant in the all ceramic joint however, the full fluid film lubrication was inhibited due to adsorbed proteins. In the metal-on-metal joints this adsorbed protein layer acted to reduce the friction while in the ceramic coupling the friction was increased. The use of bovine serum as the lubricant also significantly increased the friction in the metal-on-plastic joint.