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Controlling damage evolution in the context of fatigue plays a key role in extending the number of operational cycles. A major challenge lies in accurately capturing the material response and loading conditions. This work particularly aims at the numerical prediction of fatigue in quasi-brittle materials. Such simulations are relevant to complement experiments by completing and extending the range of cycle numbers and load paths. For this reason, the proposed study introduces a modeling framework inspired by the concept of endurance surfaces [1, 2]. This concept will be integrated into an established damage model [3], within a thermodynamically consistent and gradient-enhanced framework [4, 5].
Benchmark problems under monotonic loading conditions are first analyzed for different geometries to demonstrate the potential of this approach. Special emphasis is placed on damage mitigation by varying the loading parameters. In addition, preliminary investigations of cyclic load paths are performed in order to transition to operational loading scenarios. This study lays the foundation for future extensions to more complex load paths and a coupling with ductile damage, ultimately leading to a unified model capable of capturing fatigue behavior over a wide range of materials and cycle numbers.
[1] Ottosen, N. et al. (2008). Continuum approach to high-cycle fatigue modeling. International Journal of Fatigue 30. 996-1006.
[2] Lindström, S. et al. (2020). Continuous-time, high-cycle fatigue model: Validity range and computational acceleration for cyclic stress. International Journal of Fatigue 136. 105582.
[3] Menzel, A. et al. (2002). Anisotropic damage coupled to plasticity: Modelling based on the effective configuration concept. International Journal for Numerical Methods in Engineering 54. 1409-1430.
[4] Forest, S. (2009). Micromorphic Approach for Gradient Elasticity, Viscoplasticity, and Damage. Journal of Engineering Mechanics 135.
[5] Langenfeld, K. et al. (2020). A micromorphic approach for gradient-enhanced anisotropic ductile damage. Computer Methods in Applied Mechanics and Engineering 360. 112717.
