The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Sankaran Mahadevan - One of the best experts on this subject based on the ideXlab platform.

  • a unified multiaxial fatigue damage Model for isotropic and anisotropic materials
    International Journal of Fatigue, 2007
    Co-Authors: Sankaran Mahadevan
    Abstract:

    A unified multiaxial fatigue damage Model based on a characteristic plane approach is proposed in this paper, integrating both isotropic and anisotropic materials into one framework. Compared with most available critical plane-based Models for multiaxial fatigue problem, the physical basis of the characteristic plane does not rely on the observations of the fatigue crack in the proposed Model. The cracking information is not required for multiaxial fatigue analysis and the proposed Model can automatically adapt for very different materials experiencing different failure modes. The effect of the mean normal stress is also included in the proposed Model. The results of the proposed fatigue Life Prediction Model are validated using experimental results of metals as well as unidirectional and multidirectional composite laminates.

  • fatigue crack initiation Life Prediction of railroad wheels
    International Journal of Fatigue, 2006
    Co-Authors: Brant Stratman, Sankaran Mahadevan
    Abstract:

    A new multiaxial high-cycle fatigue initiation Life Prediction Model for railroad wheels is proposed in this paper. A general fatigue damage analysis methodology for complex mechanical components is developed and applied to the wheel/rail rolling contact fatigue problem. A 3-D elasto-plastic finite element Model is used for stress analysis. A subModeling technique is used to achieve both computational efficiency and accuracy. Then the fatigue damage in the wheel is evaluated numerically using the stress history during one revolution of the wheel rotation. The effects of wheel diameter, vertical loading, material hardness, and material fatigue properties on fatigue crack initiation Life are investigated using the proposed Model.

  • multiaxial high cycle fatigue criterion and Life Prediction for metals
    International Journal of Fatigue, 2005
    Co-Authors: Yongming Liu, Sankaran Mahadevan
    Abstract:

    A new high-cycle fatigue criterion based on the critical plane approach is proposed in this paper. Unlike most of the other multiaxial fatigue criteria based on the critical plane approach, the critical plane is directly correlated with the fatigue fracture plane. The proposed criterion has a wide range of applicability from very ductile metals to extremely brittle metals. Mean stress effect is also included in this criterion. The new fatigue criterion is then extended to a fatigue Life Prediction Model. The results of the proposed fatigue criterion and fatigue Life Prediction Model are validated with experimental results from the literature.

  • corrosion fatigue and multiple site damage reliability analysis
    International Journal of Fatigue, 2003
    Co-Authors: P Shi, Sankaran Mahadevan
    Abstract:

    Abstract This paper proposes a comprehensive seven-stage Life Prediction Model for the reliability analysis of aging aircraft structures under multiple site damage (MSD) due to corrosion fatigue. The damage process is divided into an interaction stage and a non-interaction stage in order to consider the interactions of the MSD cracks. The structural initial state at the interaction stage is determined by bridging the pitting corrosion and MSD. Once interaction sets in, progressive failure analysis is implemented through an iterative finite element analysis procedure. The onset of crack coalescence is assumed to correspond to the onset of structural failure. The probability of crack coalescence under MSD is evaluated by using system reliability concepts. An adaptive multi-modal importance sampling technique is developed for efficiency and accuracy in probabilistic Life estimation under MSD due to corrosion fatigue.

Deguang Shang - One of the best experts on this subject based on the ideXlab platform.

  • multiaxial fatigue damage parameter and Life Prediction for medium carbon steel based on the critical plane approach
    International Journal of Fatigue, 2007
    Co-Authors: Deguang Shang, Jing Deng
    Abstract:

    Abstract The tension–torsion fatigue characteristics were investigated under proportional and non-proportional loading in this paper. The fatigue cracks on the surface of multiaxial fatigue specimens were observed and analyzed by a scan electron microscope. On the basis of the investigation on the Kindil–Brown–Miller and Fatemi–Socie’s critical plane approaches, a shear strain based multiaxial fatigue damage parameter was proposed by von Mises criterion based on combining the maximum shear strain and the normal strain excursion between adjacent turning points of the maximum shear strain on the critical plane. The proposed multiaxial fatigue damage parameter does not include the weight constants. According to the proposed multiaxial fatigue damage parameter, the multiaxial fatigue Life Prediction Model was established with the Coffin–Manson equation, which is used to predict the multiaxial fatigue Life of medium-carbon steel. The results showed that the proposed multiaxial fatigue damage parameter could be used under either multiaxial proportional or non-proportional loading.

  • creep fatigue Life Prediction under fully reversed multiaxial loading at high temperatures
    International Journal of Fatigue, 2007
    Co-Authors: Deguang Shang, Guoqin Sun, Chuliang Yan, Jianhua Chen, Neng Cai
    Abstract:

    Abstract A multiaxial fatigue damage parameter based on the critical plane approach was proposed to calculate the pure fatigue damage under uniaxial/multiaxial loading at constant high temperatures. For the fully-reversed low-cycle fatigue loading under low frequency at high temperature, one-half of the maximum equivalent stress response value at cyclic stabilization is used as the creep stress to evaluate the multiaxial creep damage. The linear damage accumulation rule is used to predict the multiaxial creep-fatigue Life at high temperature. The creep-fatigue experimental data of thin tubular specimens with GH4169 superalloy and 2.25Cr–1Mo steel were used to verify the proposed creep-fatigue Life Prediction Model. The results showed that the proposed creep-fatigue damage calculation Model can be used under either uniaxial or multiaxial nonproportional loading at high temperature. The proposed Model is used to predict multiaxial creep-fatigue Life, and a good agreement is demonstrated with experimental data.

Xiaoping Huang - One of the best experts on this subject based on the ideXlab platform.

  • an engineering Model of fatigue crack growth under variable amplitude loading
    International Journal of Fatigue, 2008
    Co-Authors: Xiaoping Huang, Moan Torgeir
    Abstract:

    Fatigue crack growth in structure components subjected to variable amplitude loading is a very complex subject. Many Models have been proposed, but as yet no universal Model exists. In this paper, the concept of an equivalent stress intensity factor (SIF) range corresponding to R = 0 and a modified Wheeler Model are introduced. These innovations lead to a fatigue Life Prediction Model that depends mainly on the stress ratio and the plastic zone size ahead of the crack tip. This Model also describes the phenomena of retardation and arrest due to overload, and the acceleration due to a state of underload following an overload. The plastic zone size ahead of the crack tip is Modeled as a continuous function of the maximum applied SIF, yield strength, and plate thickness, making its calculation precise and easy. The proposed Model is validated using experimental fatigue crack growth data in 7075-T6 and 2024-T3 aluminum alloys and 350WT steel under various overload, underload, and spectrum loadings published in the literature. The predicted results are in good agreement with these test data.

Weiyue Wang - One of the best experts on this subject based on the ideXlab platform.

  • an asset residual Life Prediction Model based on expert judgments
    European Journal of Operational Research, 2008
    Co-Authors: Weiyue Wang, Wenjuan Zhang
    Abstract:

    Abstract An appropriate and accurate residual Life Prediction for an asset is essential for cost effective and timely maintenance planning and scheduling. The paper reports the use of expert judgments as the additional information to predict a regularly monitored asset’s residual Life. The expert judgment is made on the basis of measured condition monitoring parameters, and is treated as a random variable, which may be described by a probability distribution due to the uncertainty involved. Since most expert judgments are in the form of a set of integer numbers, we can either directly use a discrete distribution or use a continuous distribution after some transformation. A key concept used in this paper is condition residual Life where the residual Life at the point of checking is conditional on, among others, the past expert judgments made on the same asset to date. Stochastic filtering theory is used to predict the residual Life given available expert judgments. Artificial, simulated and real data are used for validating and testing the Model developed.

Neng Cai - One of the best experts on this subject based on the ideXlab platform.

  • creep fatigue Life Prediction under fully reversed multiaxial loading at high temperatures
    International Journal of Fatigue, 2007
    Co-Authors: Deguang Shang, Guoqin Sun, Chuliang Yan, Jianhua Chen, Neng Cai
    Abstract:

    Abstract A multiaxial fatigue damage parameter based on the critical plane approach was proposed to calculate the pure fatigue damage under uniaxial/multiaxial loading at constant high temperatures. For the fully-reversed low-cycle fatigue loading under low frequency at high temperature, one-half of the maximum equivalent stress response value at cyclic stabilization is used as the creep stress to evaluate the multiaxial creep damage. The linear damage accumulation rule is used to predict the multiaxial creep-fatigue Life at high temperature. The creep-fatigue experimental data of thin tubular specimens with GH4169 superalloy and 2.25Cr–1Mo steel were used to verify the proposed creep-fatigue Life Prediction Model. The results showed that the proposed creep-fatigue damage calculation Model can be used under either uniaxial or multiaxial nonproportional loading at high temperature. The proposed Model is used to predict multiaxial creep-fatigue Life, and a good agreement is demonstrated with experimental data.