Cohesive strength and fracture toughness of atmospheric ice

This paper aims at defining key mechanical properties of atmospheric ice in order to improve the design of mechanical de-icing systems. Based on ice fracture mechanisms, the parameters of interest are the cohesive strength of the ice and its fracture toughness. An hybrid experimental/numerical vibrating method is used to measure those critical values. Parameters such as temperature and precipitation rate influence the ice density and ice samples are thus defined with respect to this parameter. First the cohesive strength of ice is measured over the entire range of ice density and a polynomial expression of the cohesive strength of ice is given as a function of this density. Then the fracture toughness is measured for a smaller range of density and an average critical value is given. Finally, the influence of the properties computed are discussed to assess the conditions of atmospheric ice mechanical removal and the challenges for the design of mechanical ice protection systems. The study tends to show that as its density decreases, ice is more difficult to remove mechanically.