Characterization of Mode-II Interfacial Fracture Toughness of Ice/Metal Interfaces

Airborne, marine and ground structures are vulnerable to atmospheric icing in cold weather operation conditions. Most of the ice adhesion-related work have focused on the mechanical ice removal strategies because of practical considerations, while limited literature is available for fundamental understanding of the ice adhesion process. Here, we present a fracture mechanics-based approach to characterize interfacial fracture parameters for the shear behavior of a typical ice/aluminum interface. An experimental framework employing two complementary tests (1) lap shear and (2) shear push-out tests was introduced to assess the mode-II fracture parameters for the selected aluminum/ice interface. Both analytical (shear-lag analysis) and numerical (finite element analysis incorporating cohesive zone method) models were used to evaluate shear fracture parameters. The combined experimental and numerical results, as well as surveying published results for lap shear and 0° cone tests showed that mode-II interfacial strength and toughness can be significantly affected by the method of testing geometry due to geometrically induced interfacial residual stress. As a result, the apparent toughness (or strength) obtained by 0° cone test could reach an order of magnitude higher than those derived from lap shear test.