Numerical simulation and modeling of ice shedding: Process initiation

• We investigate a state of the art fracture mechanics model and obtain excellent agreement with experiment.
• We study and propose laws for the mechanical properties of atmospheric ice.
• We propose a physical mechanism for the ice shedding phenomenon.
• The mechanism relies on pressure redistribution due to hydrostatic equilibrium.
• Numerical simulations are performed and confirm the mechanism.

In aeronautics, the issue of ice shedding prediction is of prime importance in the assessment of electro-thermal ice protection systems. In this paper, an ice shedding mechanism based on pressure redistribution in the water film formed at the ice/airfoil interface is proposed. This pressure distribution induces a stress concentration that leads to crack propagation in the ice. To determine whether this mechanism is relevant or not, two numerical experiments are performed. The results of these numerical experiments and the influence of a few material parameters are discussed, as well as their limitations and possible consequences arising from some of the hypotheses.The numerical modeling is based on recent works on damage/fracture mechanics which provide a general framework for fracture mechanics computation. The effects of numerical parameters and mesh size are discussed. A mixed mode test case based on experimental data is also performed. This test case had not been attempted before on this particular numerical method, which therefore serves as further validation.