Icephobic coatings for aircraft and other surfaces subjected to ice accretion have generated great interest in the past two decades, due to the advancement of nanomaterials, coating fabrication methods, biomimetics, and a more in-depth understanding of ice nucleation and ice adhesion. Icephobic coatings have demonstrated the ability to repel water droplets, delay ice nucleation and significantly reduce ice adhesion. Despite these ongoing research activities and promising results, the findings reported hereafter suggest that coatings alone cannot be used for aircraft anti-icing and de-icing operations; rather, they should be considered as a complementary option to either thermal or mechanical ice protection methods, for reducing power consumption and the ecological footprint of these active systems and for expediting ground de-icing operations. This paper will first review the state-of-the-art of icephobic coatings for various applications, including their performance and existing deficiencies. The second part of this paper focuses on aerospace anti-icing and de-icing requirements and the need for hybrid systems to provide a complete ice protection solution. Lastly, several urgent issues facing further development in the field are discussed.

Recent research is showing growing interest in low-power electromechanical de-icing systems and, in particular, de-icing systems based on piezoelectric actuators. These systems use the vibrations generated by piezoelectric actuators at resonance frequencies to produce shear stress at the interface between the ice and the support or to produce tensile stress in the ice. This paper provides analytical and numerical models enabling a better understanding of the main de-icing mechanisms of resonant actuation systems. Different possible ice shedding mechanisms involving cohesive and adhesive fractures are analyzed with an approach combining modal, stress and crack propagation analyses. Simple analytical models are proposed to better understand the effects on ice shedding of the type of mode, ice thickness, or frequency with respect to cohesive and adhesive fractures.

a b s t r a c tThe understanding of ice shedding is of prime importance in the assessment of aeronautical ice protection systems. In this paper, the authors previously studied mechanism is extended to include adhesive debonding. It is based on pressure redistribution in the water film formed at the ice/airfoil interface. The numerical modelling of crack propagation is based on recent work on damage mechanics which provides a general framework. As for adhesive debonding an algebraic model is derived from general mechanical equilibrium relations. Numerical experiments are performed to study an adhesive-debonding/brittlefailure mode detachment, the results of which are discussed.

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