Author(s): Aleksey Marchenko
Linked Author(s):
Keywords: Sea Ice; Lake Ice; Ice Mechanics and Properties
Abstract: Model of transversally isotropic material is used to describe properties of layered and fiber materials both. The axis of symmetry is orthogonal to layers in layered materials, and parallel to fibers in fiber materials. Transversally isotropic model is used to describe elastic properties of single ice crystal Ih, where basal planes are considered as layers and the optical axis is the axis of symmetry. In the present paper columnar ice S2 is considered as transversally isotropic material where the axis of symmetry is parallel to the columns, i.e. it is vertical. Transversally isotropic model includes five rheological constants. The rheological constants are elastic moduli and Poisson’s ratios in vertical and horizontal directions, and shear modulus in vertical direction. For the calculation of five rheological constants a set of 5 tests was performed with saline and fresh ice samples taken from the same depth of sea ice and lake ice. The samples were rectangular ice blocks with size of about 3-5 cm, and ice beams with sizes of about 20x3x3 cm. Tests included measurements of speeds of p-waves in vertical, horizontal, and inclined to vertical directions in the ice blocks, and measurements of natural frequencies of bending oscillations of vertical and horizontal ice beams. Vertical and horizontal elastic moduli were reconstructed from natural frequencies of the beams, Poisson’s ratios and the shear coefficient were then calculated using the speeds of p-waves measured in ice blocks. It was discovered that vertical elastic moduli are greater the horizontal elastic moduli, and speeds of p-waves are greater in vertical direction than in horizontal directions. Further data processing showed that in few tests Poisson’s ratios in vertical direction were greater Poisson’s ratios in horizontal directions.
Year: 2022