Bridging local parameters with global mechanical properties in bonded discrete elements for ice load prediction on conical structures

Abstract

Discrete Element Method (DEM) with inter-element bond has emerged as a promising numerical approach to simulate the ice-structure interaction. This approach simulates ice physically during pre- and post-failure, and thus offers reasonable ice load predictions when the ice mechanical properties are modeled accurately. However, achieving the desired mechanical properties in DEM often requires extensive trial-and-error process. This paper attempts to alleviate the iterative work by investigating the effect of various DEM parameters on the simulated mechanical properties, especially the Young's modulus, the flexural strength and the compressive strength. Furthermore, the study focuses on simulating ice with a low element count. This avoids impractically large simulations in ice-structure problems, which typically require the modeling of a relatively wide ice sheet.The investigation proposes a set of quantitative relationships which bridges the local DEM parameters with the global mechanical properties. This study then validates the proposed relationship across three different scales: 1) small-scale standardized material tests, 2) ice-tank model test of a conical structure in level ice, and 3) a full-scale event involving level ice and a conical jacket leg in the Bohai Sea. The simulations indicate close agreement with the experimental data, thus validating the proposed relationship as a means to determine suitable DEM parameters.