Influence of the loading direction on the uniaxial compressive strength of sea ice based on field measurements

• Published in: Annals of Glaciology
• Main Authors: Shunying Ji, Xiaodong Chen, Anliang Wang
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2020
• Subjects: Anisotropic mechanical property; ductile-to-brittle transition; loading direction; sea ice; uniaxial compressive strength; Meteorology. Climatology; QC851-999; Annals of Glaciology; Sea ice
• Online Access: https://doi.org/10.1017/aog.2020.14; https://doaj.org/article/9a29ca58f76b455abd48c2f002a60923

Sea ice is composed of columnar-shaped grains. To investigate the influence of the loading direction on the uniaxial compressive strength and failure processes of sea ice, field experiments were performed with first-year level ice. Loads were applied both horizontally (parallel to the grain columns) and vertically (across the grain columns) with various nominal strain rates. Two failure modes have been observed: a ductile failure mode at low nominal strain rates, and a brittle failure mode at high nominal strain rates. However, the failure pattern of sea ice was clearly dependent on the loading direction. At low nominal strain rates (ductile failure mode), the sea-ice samples yielded due to the development of wing cracks under horizontal loading and due to splaying out at one end under vertical loading. When sea ice fails in the ductile mode, the deformation is driven by grain boundary sliding under horizontal loading and by grain decohesion and crystal deflection under vertical loading. At high nominal strain rates (brittle failure mode), the sea-ice samples failed in shear faulting under horizontal loading and in cross-column buckling under vertical loading. The nominal strain rate at the brittle–ductile transition zone is about ten times higher under vertical loading.