Substantion of the energy approach to parameter determination of the cyclic ice force against offshore structures

Abstract

The determination of the magnitude of the ice force effect on the marine ice-resistant base structures (MIRB) is carried out according to the calculation formula accounting for adopted failure model. The ice in the contact zone can damaged with different failure mechanisms depending on ice temperature, rate etc. The model of ice elastic–brittle fracture is presented taking into account the damage of the ice cover edge by all possible types of cracks dividing the active contact zone onto wedge-shaped or trapezoidal fragments. All the processes of ice failure of different nature is proposed to consider as a complex process. The mathematical description of process in time is based on an universal energy criterion of failure. The substantiations include the phenomenological analysis of the phenomenon of cyclic ice failure in the contact zone, the results of numerical modeling of the ice cover edge in interface zone, data of physical modelling. The criterion is the limit value of the potential energy of elastic compression accumulated in unit ice volume before the structure. It is the specific elastic energy of mechanical failure of sea ice. Also the test results with ice big samples under dynamic compression are presented.