ABSTRACT
The Marginal Ice Zone (MIZ) is the transition region between open waters and the sea ice, which has an important effect on ships and offshore structures. A numerical study on the hydroelastic response of ice floes under the action of regular waves in MIZ is presented in this paper. A boundary-element method based on three-dimensional linear potential flow theory is used to predict fluid field. The finite element method is used to numerically model a large ice floe within the framework of the Mindlin plate assumption. A hydroelastic model is formulated using modal superposition method to solve the fluidstructure coupling equations. The hydroelastic response of ice floes under regular waves is studied. The influences of the wavelength and the size of an ice floe on the response are studied and discussed. The results show that the wavelength has a great influence on the displacement of ice floes and the maximum stress in the ice depends on floe size. The ultimate wave height of ice fracture against the ratio of floe length to wavelength is given. The limit wave height of the ice fracture decreases sharply with the length ratio when the floe length is small, and then keeps unchanged for larger floes.
Studying on interactions between sea ice and waves could help understand global warming, which attracted the attention of the scientific research in recent decades. The research methods on the interactions between ice floes and waves mainly include: experimental method, simplified analytical method and numerical simulation method. Experimentally, Wang et al. (2000) used composite material consisting of polypropylene powder, plastic particles and white cement, to simulate physical characteristics of ice sheets and studied the fracture under the action of waves in a flume, and the relationships between fracture of ice sheets and the ratio of sea floe length to wavelength were obtained. Frankenstein et al. (2001) used 6-DOF instruments to measure the motion of ice floes and inverted the changes in amplitude by the heave amplitude of ice floes. Sakai and Hanai (2002) studied the influence of the sizes and elastic modulus of the ice plate on the incident wavelength. They used a polyethylene material to simulate the ice plate and the results showed that the ice plate had no effect on the speed of wave propagation, when the length of the ice plate was very small. Mcgovern and Bai (2014) studied the relationship between wave characteristics and ice floe motion response by substituting paraffin wax for ice floes. The results showed that wavelength has a great effect on ice floe movement. Dolatshah and Bennets (2018) studied the hydroelastic interaction between regular waves and ice floes under different incident wave periods and steepnesses, and the results showed that the ice sheet would break only if the period and steepness were high enough.
