Numerical Simulation of Helicopter Blade Ice Shedding using a Bilinear Cohesive Zone Model

In helicopter, the icing rotor blades will decrease the effectiveness of the helicopter and endanger the lives of the pilots. The asymmetrical ice break-up and shedding could also lead to severe vibrations of the rotor blade. Ice break-up from the main rotor may strike the fuselage and tail rotor, even worse, find its way into the engine, which may cause serious aircraft accidents. An understanding of the mechanisms responsible for ice shedding process is necessary in order to optimize the helicopter rotor blade design and de-icing system to avoid hazardous ice shedding. In this paper, the ice shedding model is improved by introducing a bilinear cohesive zone model (CZM) to simulate the initiation and propagation of ice/blade interface crack. A maximum stress criterion is used to describe the failure occurred in the ice. The coupling of these two types of failure is taken into accounted in the model and the whole simulation process is fully automatically executed and controlled by a program written by the ANSYS Parametric Design Language (APDL). By using this model, the effect of centrifugal loading and vibration loading on the ice shedding from a helicopter rotor blade is studied. This model could be used to further study on optimization of the electrothermal de-icing system and ice shedding trajectory and impact simulations.