무한 빙판에서 쇄빙선박에 의한 쇄빙능력 산정에 관한 연구

Abstract

Natural resources development in Sakhalin area and the Sea of Okhotsk requires proper means of sea transportation from Russian Far East region and China. Sea routes in the Sea of Okhotsk are normally covered with sea ice of less than 1 m thickness from December to April and sea-going vessels should be equipped with sufficient icebreaking capability or at least ice-worthy hull structures.

Ice rubble pieces broken by the bow impact load and side hull of an icebreaking vessel usually pass along the ship's bottom hull and may hit the propeller/rudder or other stern structures causing serious damage to ship's hull. It is important to estimate the size of broken ice pieces during the icebreaking process. The dynamic interaction process of icebreaker with infinite ice sheet is simplified as a wedge type beam of finite length supported by elastic foundation. The wedge type ice beam is loaded with vertical impact forces due to the inclined bow stem of icebreaking vessels. The numerical model provides locations of maximum dynamic bending moment where extreme tensile stress arises and also possible fracture occurs. The model can predict a failure length of broken ice sheet given design parameters. The results are compared to analytical solution for static load and observed pattern of ice sheet failure onboard an icebreaker. The meaning of sizes of ice rubble is discussed by comparing computed failure length with the characteristic length.