Numerical Simulation of Ice Milling Loads on Propeller Blade With Cohesive Element Method

Abstract

In ice-infested waters, propellers of a polar ship are likely to be exposed to ice loads in different scenarios. Propeller milling with ice is one of the most dangerous cases for icepropeller interaction. In this study, we try to simulate dynamic milling process of icepropeller and reproduce resulting physical phenomena. Cohesive element method is used to model ice in the simulation. To simulate material properties of ice, an elastoplastic softening constitutive law is developed. Both crushing and fracture failures are included in the icepropeller milling process. The ice loads in 6 Dofs acting on blades of a propeller are calculated in time domain. The average and standard deviations of simulated dominant ice loads are compared with those from model test. A good agreement is achieved. By varying propeller rotation speed, advance velocity and cutting depth on ice block, the sensitivity study has been carried out. The results show that dominant ice loads are affected much by the three parameters. It is shown that decreasing rotation speed, or increasing advance velocity and cutting depth may lead to higher ice loads. Care should be taken to avoid overloading on propeller when operating in ice for polar ship.

Study of Continuous Icebreaking Process With Cohesive Element Method

“…CZM was applied to analyzing the behavior of ice by Mulmule and Dempsey [17,18]. Afterwards, some other researchers [19][20][21][22][23] applied CEM to simulate the interactions between level ice and marine structures.…”

“…According to the research by Cornec et al [26] and Wang et al [22], the shape of TSL curve brings limit effects on simulation results as long as the value of fracture energy is correct. The most commonly used traction-separation law in CEM is bilinear law, whose detailed expressions could refer to Wang et al [23].…”

Simulation of Ice-Propeller Collision with Cohesive Element Method

“…The propeller will rotate at a constant speed ω p = 2 rps anticlockwise, while the ice block will move towards the back of the blade along the negative direction of the x-axial. The blades were designed with reference to Stone Marine Meridian series [23][24][25]. There were ice-strengthened by increasing the thickness for navigation in ice.…”

“…In numerical simulation, the propeller model and ice block are set to be as the same as those used in the test as shown in Figure 9b. The other input parameters could refer to Wang et al [25]. Figure 8 gives the comparison between the numerical results of the presented method and the experimental results at different impact velocities.…”

“…In numerical simulation, the propeller model and ice block are set to be as the same as those used in the test as shown in Figure 9b. The other input parameters could refer to Wang et al [25].…”