Failure Analysis of Impacting Ice Floes

Bhat, Sunil; Choi, Sung-Uk; Wierzbicki, Tomasz; Karr, Dale G.

doi:10.1115/1.2919914

Cited by 19 publications

(9 citation statements)

References 0 publications

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“…Not plotted in the figure is the out-of-plane vertical force component Z F , which is primarily responsible for creating radial cracks (e.g., 0 A ) and potential circumferential cracks. For the current paper, the formation of long cracks is essentially a splitting problem due to in-plane force components X F and Y F (Bhat et al, 1991, Bhat, 1988, Dempsey et al, 1993 as plotted in Fig. 6a.…”

Section: Theoretical Model and Assumptionsmentioning

confidence: 87%

Parallel channels' fracturing mechanism during ice management operations. Part I: Theory

Lü

Lubbad

Shestov

et al. 2018

Cold Regions Science and Technology

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It is frequently observed that long cracks in sea-ice tend to form between parallel channels during ice management operations. The long cracks that develop play an important role in reducing the size of the managed ice floes, which is one of the main goals in an ice management operation. However, the fracture mechanism behind these long cracks remains unclear. To address this issue, a comprehensive study is reported here in two associated papers.In the current paper (i.e., Paper I), an edge-crack theoretical model is proposed to elucidate the parallel channels' fracture mechanism. The proposed theoretical model is partially based on theories regarding ship -level ice interactions and partially based on previous studies on the general ice fracturing mechanism. The edge-crack theoretical model is extensively examined using a separately developed numerical scheme based on the eXtended Finite Element Method (XFEM), which allows for the existence of a singularity field and displacement jump within conventional Finite Elements (i.e.., FEM). The numerical scheme is benchmarked against known asymptotic analytical solutions and field experiments. Afterwards, with the developed numerical scheme, through fitting numerical simulation results in terms of the edge crack's Stress Intensity Factors (SIFs) and a relevant asymptotical analysis, we managed to derive a group of closed-form formulae with wide application ranges. For the current engineering problem, this set of formulae quantifies the maximum parallel channel spacing max h , beyond which the observed parallel channels' fracturing events cease to occur. Moreover, the same numerical scheme is utilised to study parallel channels' fracturing paths. Based on the XFEM-based crack path simulations, a second group of formulae and a numerical recipe were obtained to characterise a simplified crack path. This set of equations enables us to quantify the maximum floe size MCD L that can be generated between two parallel channels and its corresponding floe size ratio. In the sequel paper (i.e., Paper II), these equations are validated by a series of well-controlled field experiments undertaken during the Oden Arctic Technology Research Cruise of 2015 (OATRC2015).

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Section: Theoretical Model and Assumptionsmentioning

confidence: 87%

Parallel channels' fracturing mechanism during ice management operations. Part I: Theory

Lü

Lubbad

Shestov

et al. 2018

Cold Regions Science and Technology

View full text Add to dashboard Cite

show abstract

“…There are generally two ice fracturing modes during ice structure interactions, namely, the in-plane (Dempsey et al, 1993, Bhat, 1988, Bhat et al, 1991 and out-of-plane failure modes (Lu, 2014). The out-of-plane fracture's crack extension, in the form of radial cracking, is usually rather limited in length.…”

Section: Parallel Channels' Fracture Mechanismsmentioning

confidence: 99%

Parallel channels' fracturing mechanism during ice management operations. Part II: Experiment

Lü

Lubbad

Løset

2018

Cold Regions Science and Technology

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During ice management operations, cutting parallel channels with narrow spacing in the ice using icebreakers can effectively reduce the size of ice floes reaching the protected vessel/structure. A narrow channel spacing width generates smaller ice floes. However, a spacing that is too narrow can lead to excessive or even impractical ice management operations. Therefore, it is beneficial to establish a theoretical model that correlates the channel spacing width with the frequency of ice fracturing events and the reduction of managed ice floe sizes. This is achieved in the current study with two sequential papers, i.e. Papers I and II. In Paper I, a theoretical model involving an 'edge crack model' was formulated to predict the following conditions for an ice management operation: 1) the maximum ice floe with size MCD L that can be produced; 2) the maximum channel spacing width max h beyond which long cracks will not develop between the channels; and 3) the required force to initiate long cracks between parallel channels. In this paper (Paper II), we describe two dedicated 'parallel channel tests' conducted separately on September 26 th and 29 th in 2015 during an expedition to the Arctic Ocean (around 82 o N and 16 o E) with the icebreakers Oden and Frej. The tests had 'well-controlled' channel spacing in each test run. Several different channel spacing values were tested with the Oden and the consequent fracturing information was documented by camera images. Image processing enabled us to extract information, such as maximum floe sizes and floe size distributions, given different channel spacing widths. In addition, the ship's data, such as ship velocity and propulsion history, enabled us to validate the theoretical model's capability to predict the onset of long cracks between two parallel channels. Despite uncertainties (e.g., non-uniform ice thickness, fracture properties of sea ice, etc.) involved in the tests, favourable comparisons between the experimental results and the theoretical predictions were achieved. Both the theoretical model and experimental results help clarify the parallel channel fracturing mechanism.

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“… Bhat [1988, 1989], studied the propagation of cracks in an ice floe leading to a splitting failure. The load required to achieve global splitting failure under relatively high impact velocities can be reached early in the radial crack propagation process (when the crack length is a small fraction of the floe size).…”

Section: Research In Ice Mechanicsmentioning

confidence: 99%

Recent Progress in Snow and Ice Research

Richter-Menge

Colbeck

Jezek

1991

Reviews of Geophysics

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Snow and ice research during the past quadrennial covers a wide range of topics varying from the climatic effects of large ice sheets and sea ice covers to applied problems such as the icing of power lines and communication facilities. This review focuses in more detail on three topics of the many subjects investigated to provide a more coherent look at the advances achieved and prospects for the future. These are: the influences of layers in seasonal snow covers; research in ice mechanics on freshwater and sea ice; and remote sensing of polar ice sheets. These topics provide useful examples of the general needs in snow and ice research applicable to most areas, e.g. better representation in models of detailed processes, careful controlled laboratory experiments to quantify processes, and field studies to provide the appropriate context for interpretation of processes from remote sensing.

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Failure Analysis of Impacting Ice Floes

Cited by 19 publications

References 0 publications

Parallel channels' fracturing mechanism during ice management operations. Part I: Theory

Parallel channels' fracturing mechanism during ice management operations. Part I: Theory

Parallel channels' fracturing mechanism during ice management operations. Part II: Experiment

Recent Progress in Snow and Ice Research

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