For icebreakers to navigate polar routes, the ability to break through ice sheet is extremely important. To quantify this, technology that can estimate the mechanical behaviors of ice and ships is essential. The purpose of this study is to analyze the response of the icebreaker Araon breaking through ice sheet. Drucker-Prager yield function and fracture energy based on continuum damage mechanics were applied to the single prism ice compression simulation. The damage in the single ice initiated and evolved as the yield function and fracture energy were assigned. The icebreaking pattern was analyzed from the cone-ice sheet interaction simulations. Patterns similar to those of previous studies were observed qualitatively. The free decay of Araon was numerically analyzed using the Hydrodynamic plug-in HydroQus that was recently developed by present authors, and very accurate ship motion responses were confirmed. The effect of hydrodynamic forces on ice resistance was analyzed through ice sheet breaking simulations. It was found that radiation forces significantly affect the heave and pitch motions of the icebreaker and increase ice resistance. HydroQus has proven to be able to efficiently and accurately simulate the ship-ice interactions compared to other approaches such as computational fluid dynamics.