Experimental and numerical analyses of elastic-plastic responses of ship plates under ice floe impacts

Due to ice floe impacts or iceberg collisions, the side structures of ships and offshore platforms operating in Arctic region may experience permanent deformations, which may have significant influences on their structural safety and working performance. To provide insight into the plastic deformations of plates, this paper investigates the nonlinear elastic-plastic responses of plates impacted by an ice wedge striker and an idealized rigid striker by both experimental and numerical methods. The ice material model based on a soil and concrete material model is used in ANSYS/LS-DYNA program to simulate the ice mechanical behaviour in an ice-plate impact scenario. Good correlation is obtained between the experimental, numerical and analytical results for plastic deformations of plate and collision forces. The comparisons of elastic-plastic responses of plate under these two strikers are conducted by both model tests and numerical simulations. Besides, a series of numerical calculations are carried out to study the differences of ice-plate impact and rigid striker-plate impact. The plastic deformations and energy absorption of plate, energy dissipation of ice damage are investigated. Moreover, for these specific cases studied, an energy absorption reduction factor (EARF) of plate under ice impact compared to rigid striker impact is proposed to estimate the structural damage, which provide some useful information for the design of ship plate against ice impact.