Study on Damage-coupled Cyclic Plastic Constitutive Model of U75V Rail Steel
In order to address the whole-life ratcheting behavior of U75V rail steel for heavy-haul railways and subways in China,the damage-coupled cyclic plastic constitutive model of U75V rail steel is investigated in this paper.Firstly,the whole-life ratcheting behavior of U75V rail steel at room temperature is studied through cyclic experiments with different average stresses and different stress amplitudes;subsequently,a damage-coupled cyclic plastic constitutive model is proposed in the framework of damage mechanics and cyclic plasticity.The proposed model incorporates the damaged-coupled Chaboche kinematic hardening model and exponential damage evolution law.Finally,based on the observed failure modes of the material in the experiments,the critical value of the damage variable is adopted as the fatigue failure criterion for predicting the failure life.Results demonstrate that when the cycle is stable,the simulated ratcheting strain rate error is below 22.0%,while it reaches 38.0%during cycle failures.The predicted fatigue life of U75V rail steel falls within the 1.5 times error band.Overall,the developed damage-coupled cyclic plastic constitutive model effectively describes the whole-life ratcheting behavior of U75V rail steel subjected to cyclic asymmetric uniaxial stress loadings.
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