Title Dynamic response of a flat plate subjected to compression force during vertical and oblique impacts with calm water Type Article Keywords Hydroelastic response, Vertical and oblique impacts, Compression force, Wet frequency, Yielding Abstract An existing hydroelastic model is extended for a flat plate subjected to a compression force with spiral spring boundary conditions during water entry. Both vertical and oblique impacts of the plate into calm water are investigated. A longitudinal strip of the plate is analyzed by fully coupling hydrodynamic pressure with elastic responses. Hydrodynamic pressure is determined by potential flow theory and plate deflections are expressed in terms of dry normal modes. The plate deflections are validated through comparison with available asymptotic models, semi-analytical and experimental results. The effect of compression force on the plate deflection is investigated at the midpoint considering different horizontal velocities and inclination angles. Dry and wet frequencies and the minimum threshold values of the compression forces are obtained for plates with different boundary conditions during vertical and oblique impacts. The results show that the plate responses may reach the plastic region at low compression force and high horizontal velocity. It is also found that for all the cases studied yielding occurs before buckling during water impact of the plate. Researchers Hashem Moradi (First researcher) , Hassan Haddadpour (Third researcher)