Analysis of Failure of (Quasi-)brittle Structure: Comparison Between Experimental Prediction and Phase Field Damage Model

Predicting the maximum load that a (quasi-)brittle specimen can sustain, and the right crack path is an important scientific and practical issue. A natural approach is to search for a criterion. Strength and toughness criteria are well suited for simple specimens having either no defect or an existing crack. When defects are present, the criterion is more complex to set up. During these last decades, many models show their ability to predict both critical loads and crack paths. We can cite Thick Level Set models (TLS) [Moës et al. 2011, ZGHAL et al. 2018], Phase Field damage model [Miehe et al. 2010, Wu et al. 2020] and recently Lip Field damage model [Moes et Chevaugeon. 2021, Chevaugeon et Moes. 2022]. This work aims to show the capability of the unified formulation of phase field damage model [Wu 2017] to predict both critical loads and crack paths in the studied structure. First, we will present the implementation of the unified formulation on FeniCS, then we will detail the precautions to be taken at the level of the modeling, in particular at the level of the choice of the mesh and of the phase field characteristic length. In a second step, we will present test case simulations of structures with defects. The simulation results will be compared to experimental results. The obtained results show a good agreement between experiment and prediction obtained by the unified phase field formulation.