EXPERIMENTAL STUDY ON SEA ICE TENSILE STRENGTH BASED ON BRAZILIAN TESTS1)

Abstract

The tensile strength of sea ice is one of the fundamental mechanical properties as well as a key parameter for the design of ships and offshore structures in ice-infected waters. For the determination of the tensile strength of brittle materials, the Brazilian test has advantages on sample preparation and loading procedure compared with the traditional method of uniaxial tension tests. To study the tensile strength of sea ice, the Brazilian tests were carried out on the sea ice with granular structure, which was collected in the Liaodong Bay of Bohai Sea. The load and loading plate displacement were recorded while the final failure pattern was photographed. Besides, the ice texture, salinity, temperature and density were also measured. The tests were performed on the ice samples with various thicknesses, temperatures and loading speeds. To calculate the tensile strength with high precision, the ice deformation is considered to improve the conventional formula. In all the experiments the ice samples failed in splitting manner. It means that the ice sample failed by reaching its tensile strength and the method works as initial expectation. The results show that the tensile strength has weak dependency on the loading speed and sample thickness but strong dependency on the total porosity. The tensile strength increased from 1.0 MPa to 2.8 MPa when total porosity decreased from 75‰ to 10‰. The results were compared with the tensile strength from uniaxial tension tests. It shows that both results have a similar trend where the total porosity and the tensile strength are in a negative relationship. However, the values of tensile strength from granular ice samples were higher than expectation. This study has identified that all the samples failed in expected pattern and the experiments provided reasonable results. It is a potential alternative for the investigation of tensile strength of sea ice.