Fracture of an ice floe: Local out-of-plane flexural failures versus global in-plane splitting failure

- Analytical solutions of four different failure scenarios are presented.
- Evaluating an existing closed-form mathematical solution to our specific application
- An ice floe's failure pattern under the floe size influence was illustrated.
- A failure map is constructed.
- Failure scenarios' competition is quantified.

Sloping structures have gained increasing interests in recent years due to their capability of breaking the incoming level ice in a dominant bending failure mode. However, 'level ice' is a theoretical simplification. A typical ice field in the Arctic consists of discontinuous ice features, such as ice floes of varying sizes. This forms a naturally broken ice field. As Arctic exploration and exploitation advance into deeper waters, floating structures are usually employed with support from ice management operations to manually create a broken ice field. Therefore, a general approach towards ice-sloping structure interactions, in which the floe size is a major variable, is proposed in this paper. In this context, two failure modes have been frequently observed, i.e., the local out-of-plane flexural failure and the global in-plane splitting failure mode. Depending on the size of the floe ice, the out-of-plane flexural failure mode can further be categorised into: 1) direct rotation of a small ice floe, 2) radial/circumferential cracking of a finite size ice floe, and 3) circumferential crack formation within a semi-infinite ice floe. These categories together with the in-plane failure mode make a total of four possible failure scenarios for floe ice. One contribution of this paper is the search for analytical closed-form solutions to evaluate the aforementioned four failure scenarios. Substantial efforts have been directed towards transferring an existing closed-form solution based on the Symplectic Mechanics to estimate the critical force that causes the radial/circumferential cracking failure scenario. In addition, previously published analytical solutions were compiled to examine the critical force that causes the remaining three failure scenarios. With the available analytical solutions, we quantify different failure scenarios' competitions. Particularly, failure maps can be constructed according to the floe size, ice thickness and associated ice material properties. The compiled analytical solutions can be easily implemented within a multi-body dynamic simulator to examine the performance of sloping structures in an ice field covering a large temporal and spatial scale.