A two-scale continuum constitutive modelling approach for predictions of fatigue-induced damage in cemented granular materials

  • Le, Vinh T (Monash University)
  • Bui, Ha H (Monash University)
  • Nguyen, Giang D (The University of Adelaide)

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Fatigue-induced damage is a common issue in cemented materials that involves the progressive formation and propagation of fatigue cracks, which tend to localize on weak or fracture planes, leading to inhomogeneous deformation within material domains. Predicting this type of damage accurately is challenging, as it requires accounting for the strain discontinuity across fracture planes and the complex evolution of cracks from initiation to propagation and eventual failure. This talk will address this challenge by presenting a new constitutive model that enriches the kinematic structure to facilitate interaction between the material responses of cracks and the outer bulk, contributing to the overall macro behaviour of materials. Moreover, the proposed model includes a new cohesive-frictional fatigue model that couples damage mechanics and bounding surface plasticity to describe the fatigue behaviour of fracture planes/cracks. As the proposed model features a characteristic length scale, it is capable of capturing size-dependent behaviour and overcoming the mesh-dependence issue. The model's validity is demonstrated through its ability to capture nonlinear fatigue damage under constant cyclic loading and simulate the propagation of fatigue fracture process zones. Furthermore, the model effectively captures the significant impact of stress amplitudes on the fatigue lives of materials, making it an essential tool for predicting and mitigating fatigue-induced damage in cemented materials.