“…This model accounted for the individual ice floes broken of the ice sheet and, as such, bears resemblance to some earlier models [10][11][12]. The model yielded the maximum peak ice load value (here and in the further text, superscript p refers to peak ice load) [6]…”
Section: Introductionmentioning
confidence: 58%
“…This paper introduces a novel, but rather simple, approach for the analysis of maximum peak ice load events on a wide, inclined, offshore structure. The model development is based on hundreds of FEM-DEM-simulations [4,5] and the introduced model extends our buckling model for peak ice loads [6].…”
Section: Introductionmentioning
confidence: 99%
“…The first figure shows the initial vertical velocity perturbation v 0 , which was used to vary initial conditions as decribed in Ranta [13]. Here the ice sheet thickness h was 1.25 m. The figure is reproduced from Ranta et al [6].…”
This paper focuses on mechanisms that limit the sea ice loads on offshore structures. It introduces a probabilistic limit load model, which can be used to analyze peak ice load events and to estimate the maximum peak ice load values on a wide, inclined, offshore structure. The model is based on simple mechanical principles, and it accounts for a mixed-mode ice failure process that includes buckling and local crushing of ice. The model development is based on observations on two-dimensional combined finite-discrete element method simulations on the ice-structure interaction process. The paper also presents a numerical limit load algorithm, which is an extension of the probabilistic limit load model and capable of yielding a large number of stochastic peak ice load values. The algorithm is compared to simulation-based and full-scale observations. Analyzing peak ice load events is challenging as sea ice goes through a complex mixed-mode failure process during such events. The algorithm is an effective tool for this analysis, and it shows that distinguishing between the buckling and local crushing failure is virtually impossible if the only data available from a peak load event is the value of the peak ice load. The algorithm shows potential in improving estimates of maximum peak ice load values on offshore structures.
“…This model accounted for the individual ice floes broken of the ice sheet and, as such, bears resemblance to some earlier models [10][11][12]. The model yielded the maximum peak ice load value (here and in the further text, superscript p refers to peak ice load) [6]…”
Section: Introductionmentioning
confidence: 58%
“…This paper introduces a novel, but rather simple, approach for the analysis of maximum peak ice load events on a wide, inclined, offshore structure. The model development is based on hundreds of FEM-DEM-simulations [4,5] and the introduced model extends our buckling model for peak ice loads [6].…”
Section: Introductionmentioning
confidence: 99%
“…The first figure shows the initial vertical velocity perturbation v 0 , which was used to vary initial conditions as decribed in Ranta [13]. Here the ice sheet thickness h was 1.25 m. The figure is reproduced from Ranta et al [6].…”
This paper focuses on mechanisms that limit the sea ice loads on offshore structures. It introduces a probabilistic limit load model, which can be used to analyze peak ice load events and to estimate the maximum peak ice load values on a wide, inclined, offshore structure. The model is based on simple mechanical principles, and it accounts for a mixed-mode ice failure process that includes buckling and local crushing of ice. The model development is based on observations on two-dimensional combined finite-discrete element method simulations on the ice-structure interaction process. The paper also presents a numerical limit load algorithm, which is an extension of the probabilistic limit load model and capable of yielding a large number of stochastic peak ice load values. The algorithm is compared to simulation-based and full-scale observations. Analyzing peak ice load events is challenging as sea ice goes through a complex mixed-mode failure process during such events. The algorithm is an effective tool for this analysis, and it shows that distinguishing between the buckling and local crushing failure is virtually impossible if the only data available from a peak load event is the value of the peak ice load. The algorithm shows potential in improving estimates of maximum peak ice load values on offshore structures.
“…The failure of an ice sheet against an inclined structure has also been studied with a combined 2D FEM-DEM, where the ice sheet and its fracture are modelled with FEM, while the contact forces between the colliding ice blocks are calculated with DEM [ 40 ]. Simulations with this model have provided a number of observations: (i) the failure process includes pile-up, ride-up, shear and pile collapse events [ 93 ]; (ii) the most important parameters are the ice thickness and compressive strength, and the inclination angle [ 8 , 94 , 95 ]; (iii) the importance of parameters change during the failure process [ 95 ]; and (iv) the load is transmitted though the rubble by force chains and is limited by buckling of the load chains [ 2 , 96 ]. The model used in these rubbling studies is deterministic, but very sensitive to initial conditions.…”
Section: Discrete Element Methods Simulation Of Sea Ice and Ice–structmentioning
confidence: 99%
“… Figure 1. Two snapshots from different stages of a DEM simulation where an intact ice sheet moved from the left against an inclined structure on the right and failed into discrete blocks, which then formed a rubble pile [ 2 ]. L refers to the amount of ice pushed against the structure.…”
Sea ice loads on marine structures are caused by the failure process of ice against the structure. The failure process is affected by both the structure and the ice, thus is called ice–structure interaction. Many ice failure processes, including ice failure against inclined or vertical offshore structures, are composed of large numbers of discrete failure events which lead to the formation of piles of ice blocks. Such failure processes have been successfully studied by using the discrete element method (DEM). In addition, ice appears in nature often as discrete floes; either as single floes, ice floe fields or as parts of ridges. DEM has also been successfully applied to study the formation and deformation of these ice features, and the interactions of ships and structures with them. This paper gives a review of the use of DEM in studying ice–structure interaction, with emphasis on the lessons learned about the behaviour of sea ice as a discontinuous medium.This article is part of the theme issue ‘Modelling of sea-ice phenomena’.
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