<p>Traditional continuum mechanics struggles with dealing with discontinuities such as fatigue cracks, whereas peridynamics, with its non-local traits, is of advantage at simulating fracture process. In this study, an ordinary state based peridynamics framework is developed, for the first time, to model cyclic plasticity, cyclic viscoplasticity, and fatigue crack growth of a nickel-based superalloy at both room and high temperatures. In particular, nonlinear isotropic and kinematic hardening effects are incorporated into the framework to capture key cyclic stress–strain responses for both time-independent and time-dependent loading conditions. Based on cumulative energy release rate, a bond-breaking criterion is proposed to naturally simulate the process of crack propagation under fatigue within the peridynamics framework, including the effects of stress ratio, loading frequency and dwell times. The developed framework is thoroughly evaluated using experimental data available in literature, proving its reliability in predicting failure behaviors of metallic alloys under fatigue loading. The framework has a great potential in aiding structural integrity assessment of load-bearing components and structures made of high-performance superalloys.</p>

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Ordinary state based peridynamics for modelling cyclic plasticity, cyclic viscoplasticity and fatigue crack growth

  • Shengbao Lu,
  • Liguo Zhao

摘要

Traditional continuum mechanics struggles with dealing with discontinuities such as fatigue cracks, whereas peridynamics, with its non-local traits, is of advantage at simulating fracture process. In this study, an ordinary state based peridynamics framework is developed, for the first time, to model cyclic plasticity, cyclic viscoplasticity, and fatigue crack growth of a nickel-based superalloy at both room and high temperatures. In particular, nonlinear isotropic and kinematic hardening effects are incorporated into the framework to capture key cyclic stress–strain responses for both time-independent and time-dependent loading conditions. Based on cumulative energy release rate, a bond-breaking criterion is proposed to naturally simulate the process of crack propagation under fatigue within the peridynamics framework, including the effects of stress ratio, loading frequency and dwell times. The developed framework is thoroughly evaluated using experimental data available in literature, proving its reliability in predicting failure behaviors of metallic alloys under fatigue loading. The framework has a great potential in aiding structural integrity assessment of load-bearing components and structures made of high-performance superalloys.