The Experts below are selected from a list of 93828 Experts worldwide ranked by ideXlab platform

David P. Kihl - One of the best experts on this subject based on the ideXlab platform.

  • Stochastic fatigue damage accumulation in a T-welded joint accounting for the residual stress fields
    International Journal of Fatigue, 2001
    Co-Authors: Shahram Sarkani, George Michaelov, David P. Kihl
    Abstract:

    Abstract The residual stresses that occur as a result of nonhomogeneous heating and cooling during welding may have a significant effect on the accumulation of fatigue damage in a welded joint. The problem is complicated not because of the complex spatial distribution of the residual stress fields, but because those fields typically change under an applied load. The present study considers the effect of residual stresses on fatigue damage accumulation in a welded joint subjected to stochastic loading. The influence of residual stresses on stochastic fatigue damage accumulation is accounted for by a simple approach based on an elastic–perfectly-plastic Material Model and the Gerber correction factor. The Model assumes that the residual stress remaining at the critical location depends on the largest nominal stress ever endured by a welded joint. The Model predicts that the residual stresses during stochastic loading randomly decay to zero. The effect of Material yielding is additionally investigated by considering an elastic–plastic Material Model with linear kinematic hardening. The residual stresses in this case are computed through Monte Carlo simulations. It is demonstrated that the effect of Material hardening is to reduce the rate of residual stress decay and thus to accelerate the rate of fatigue damage accumulation.

Shahram Sarkani - One of the best experts on this subject based on the ideXlab platform.

  • Nondestructive Evaluation of Residual Stresses in Welded Joints with Application to Stochastic Fatigue Damage Accumulation
    NDT Methods Applied to Fatigue Reliability Assessment of Structures, 2004
    Co-Authors: Shahram Sarkani, George Michaelov, Loren D. Lutes
    Abstract:

    Some of the most popular techniques for nondestructive evaluation of residual stresses in welded joints are described. Particular attention is paid to the X-ray diffraction and neutron diffraction method. The neutron diffraction method is the only nondestructive technique that is able to provide a complete, through-thickness distribution of the residual stresses in welded joints. The information on residual stresses is particularly important for fatigue damage calculation under stochastic loadings. It is demonstrated that the influence of residual stresses on stochastic fatigue damage accumulation may be incorporated by a simple approach based on elastic-perfectly-plastic Material Model and the Gerber correction factor. The Model assumes that the remaining residual stress at the critical location depends on the largest nominal stress ever seen by a welded joint. The Model predicts that the residual stresses during stochastic loading randomly decay to zero. The effect of Material yielding is additionally investigated by considering an Elastic-Plastic Material Model with linear kinematic hardening. The residual stresses in this case are computed through Monte-Carlo simulations. It is demonstrated that the effect of Material hardening is to reduce the rate of residual stress decay and thus to accelerate the rate of fatigue damage accumulation.

  • Stochastic fatigue damage accumulation in a T-welded joint accounting for the residual stress fields
    International Journal of Fatigue, 2001
    Co-Authors: Shahram Sarkani, George Michaelov, David P. Kihl
    Abstract:

    Abstract The residual stresses that occur as a result of nonhomogeneous heating and cooling during welding may have a significant effect on the accumulation of fatigue damage in a welded joint. The problem is complicated not because of the complex spatial distribution of the residual stress fields, but because those fields typically change under an applied load. The present study considers the effect of residual stresses on fatigue damage accumulation in a welded joint subjected to stochastic loading. The influence of residual stresses on stochastic fatigue damage accumulation is accounted for by a simple approach based on an elastic–perfectly-plastic Material Model and the Gerber correction factor. The Model assumes that the residual stress remaining at the critical location depends on the largest nominal stress ever endured by a welded joint. The Model predicts that the residual stresses during stochastic loading randomly decay to zero. The effect of Material yielding is additionally investigated by considering an elastic–plastic Material Model with linear kinematic hardening. The residual stresses in this case are computed through Monte Carlo simulations. It is demonstrated that the effect of Material hardening is to reduce the rate of residual stress decay and thus to accelerate the rate of fatigue damage accumulation.

Soren Ostlund - One of the best experts on this subject based on the ideXlab platform.

  • orthotropic elastic plastic Material Model for paper Materials
    International Journal of Solids and Structures, 2003
    Co-Authors: Petri Makela, Soren Ostlund
    Abstract:

    Paper and paperboard generally exhibit anisotropic and non-linear mechanical Material behaviour. In this work, the development of an orthotropic elastic plastic constitutive Model, suitable for Modelling of the Material behaviour of paper is presented. The anisotropic Material behaviour is introduced into the Model by orthotropic elasticity and an isotropic plasticity equivalent transformation tensor. A parabolic stress-strain relation is adopted to describe the hardening of the Material. The experimental and numerical procedures for evaluation of the required Material parameters for the Model are described. Uniaxial tensile testing in three different inplane Material directions provides the calibration of the Material parameters under plane stress conditions. The numerical implementation of the Material Model is presented and the Model is shown to perform well in agreement with experimentally observed mechanical behaviour of paper.

  • Orthotropic elastic–plastic Material Model for paper Materials
    International Journal of Solids and Structures, 2003
    Co-Authors: Petri Makela, Soren Ostlund
    Abstract:

    Paper and paperboard generally exhibit anisotropic and non-linear mechanical Material behaviour. In this work, the development of an orthotropic elastic plastic constitutive Model, suitable for Modelling of the Material behaviour of paper is presented. The anisotropic Material behaviour is introduced into the Model by orthotropic elasticity and an isotropic plasticity equivalent transformation tensor. A parabolic stress-strain relation is adopted to describe the hardening of the Material. The experimental and numerical procedures for evaluation of the required Material parameters for the Model are described. Uniaxial tensile testing in three different inplane Material directions provides the calibration of the Material parameters under plane stress conditions. The numerical implementation of the Material Model is presented and the Model is shown to perform well in agreement with experimentally observed mechanical behaviour of paper.

George Michaelov - One of the best experts on this subject based on the ideXlab platform.

  • Nondestructive Evaluation of Residual Stresses in Welded Joints with Application to Stochastic Fatigue Damage Accumulation
    NDT Methods Applied to Fatigue Reliability Assessment of Structures, 2004
    Co-Authors: Shahram Sarkani, George Michaelov, Loren D. Lutes
    Abstract:

    Some of the most popular techniques for nondestructive evaluation of residual stresses in welded joints are described. Particular attention is paid to the X-ray diffraction and neutron diffraction method. The neutron diffraction method is the only nondestructive technique that is able to provide a complete, through-thickness distribution of the residual stresses in welded joints. The information on residual stresses is particularly important for fatigue damage calculation under stochastic loadings. It is demonstrated that the influence of residual stresses on stochastic fatigue damage accumulation may be incorporated by a simple approach based on elastic-perfectly-plastic Material Model and the Gerber correction factor. The Model assumes that the remaining residual stress at the critical location depends on the largest nominal stress ever seen by a welded joint. The Model predicts that the residual stresses during stochastic loading randomly decay to zero. The effect of Material yielding is additionally investigated by considering an Elastic-Plastic Material Model with linear kinematic hardening. The residual stresses in this case are computed through Monte-Carlo simulations. It is demonstrated that the effect of Material hardening is to reduce the rate of residual stress decay and thus to accelerate the rate of fatigue damage accumulation.

  • Stochastic fatigue damage accumulation in a T-welded joint accounting for the residual stress fields
    International Journal of Fatigue, 2001
    Co-Authors: Shahram Sarkani, George Michaelov, David P. Kihl
    Abstract:

    Abstract The residual stresses that occur as a result of nonhomogeneous heating and cooling during welding may have a significant effect on the accumulation of fatigue damage in a welded joint. The problem is complicated not because of the complex spatial distribution of the residual stress fields, but because those fields typically change under an applied load. The present study considers the effect of residual stresses on fatigue damage accumulation in a welded joint subjected to stochastic loading. The influence of residual stresses on stochastic fatigue damage accumulation is accounted for by a simple approach based on an elastic–perfectly-plastic Material Model and the Gerber correction factor. The Model assumes that the residual stress remaining at the critical location depends on the largest nominal stress ever endured by a welded joint. The Model predicts that the residual stresses during stochastic loading randomly decay to zero. The effect of Material yielding is additionally investigated by considering an elastic–plastic Material Model with linear kinematic hardening. The residual stresses in this case are computed through Monte Carlo simulations. It is demonstrated that the effect of Material hardening is to reduce the rate of residual stress decay and thus to accelerate the rate of fatigue damage accumulation.

Petri Makela - One of the best experts on this subject based on the ideXlab platform.

  • orthotropic elastic plastic Material Model for paper Materials
    International Journal of Solids and Structures, 2003
    Co-Authors: Petri Makela, Soren Ostlund
    Abstract:

    Paper and paperboard generally exhibit anisotropic and non-linear mechanical Material behaviour. In this work, the development of an orthotropic elastic plastic constitutive Model, suitable for Modelling of the Material behaviour of paper is presented. The anisotropic Material behaviour is introduced into the Model by orthotropic elasticity and an isotropic plasticity equivalent transformation tensor. A parabolic stress-strain relation is adopted to describe the hardening of the Material. The experimental and numerical procedures for evaluation of the required Material parameters for the Model are described. Uniaxial tensile testing in three different inplane Material directions provides the calibration of the Material parameters under plane stress conditions. The numerical implementation of the Material Model is presented and the Model is shown to perform well in agreement with experimentally observed mechanical behaviour of paper.

  • Orthotropic elastic–plastic Material Model for paper Materials
    International Journal of Solids and Structures, 2003
    Co-Authors: Petri Makela, Soren Ostlund
    Abstract:

    Paper and paperboard generally exhibit anisotropic and non-linear mechanical Material behaviour. In this work, the development of an orthotropic elastic plastic constitutive Model, suitable for Modelling of the Material behaviour of paper is presented. The anisotropic Material behaviour is introduced into the Model by orthotropic elasticity and an isotropic plasticity equivalent transformation tensor. A parabolic stress-strain relation is adopted to describe the hardening of the Material. The experimental and numerical procedures for evaluation of the required Material parameters for the Model are described. Uniaxial tensile testing in three different inplane Material directions provides the calibration of the Material parameters under plane stress conditions. The numerical implementation of the Material Model is presented and the Model is shown to perform well in agreement with experimentally observed mechanical behaviour of paper.