Physical modelling of ship/ice interaction: Report 2. Parametric model study of ships ramming multi-year ice floes

Claude Daley, Seppo Kivimaa

Research output: Book/ReportReport

Abstract

The report describes the second and final phase of a joint research project between Canada and Finland. The objective of the work was to experimentally investigate the mechanics of a ship ramming a massive ice floe. In the first phase, models of the vessel M.V. Arctic were tested and compared with full scale data. While the model/full scale agreement was encouraging, concern was raised about the influence of ship size, bow form, ice strength scaling and other parameters on the ramming forces and ship hull response. In the second phase, described herein, these questions were addressed by testing a model of a very large vessel (150 000 tonne) and a model of the M.V. Canmar Kigoriak (6 700 tonne). Both models consisted of multiple segments connected to a flexible backbone. Ramming forces and vessel dynamic response were measured. Altogether 107 tests were conducted with these models. The results of the tests are summarised in this report. The main result of the project is the understanding of the ramming process and the ways in which the ship and ice parameters influence the vessel response. The main engineering concern is the maximum bending moment that may occur in the hull girder. It is shown that two separate processes take place during ramming. These can be called initial impact phase and beaching phase. There are cases in which only quasi-static beaching is important, especially for a large ship striking a square ice edge. Dynamically amplified interaction forces of the initial impact phase in some cases may be nearly 50 % larger, and the resulting bending moments may be nearly 100 % larger than those of the quasi-static case. The main factors contributing to dynamics of interaction forces are vessel size, bow form, size of previous imprint and ice strength. Velocity linearly influences force and bending moment, but does not affect the degree of dynamic amplification. The results have implications to both design and operation of Arctic vessels.
Original languageEnglish
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Number of pages66
ISBN (Print)951-38-3992-3
Publication statusPublished - 1991
MoE publication typeD4 Published development or research report or study

Publication series

SeriesValtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports
Number744
ISSN0358-5077

Fingerprint

vessel
ice
modeling
hull
dynamic response
mechanics
ship
amplification
engineering
beaching
test
parameter

Keywords

  • ice
  • sea ice
  • icebreakers
  • ice disintegration
  • ice loads
  • ships
  • interactions
  • ship hulls
  • dynamic loads
  • loads (forces)
  • ship models

Cite this

Daley, C., & Kivimaa, S. (1991). Physical modelling of ship/ice interaction: Report 2. Parametric model study of ships ramming multi-year ice floes. Espoo: VTT Technical Research Centre of Finland. Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports, No. 744
Daley, Claude ; Kivimaa, Seppo. / Physical modelling of ship/ice interaction : Report 2. Parametric model study of ships ramming multi-year ice floes. Espoo : VTT Technical Research Centre of Finland, 1991. 66 p. (Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports; No. 744).
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Daley, C & Kivimaa, S 1991, Physical modelling of ship/ice interaction: Report 2. Parametric model study of ships ramming multi-year ice floes. Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports, no. 744, VTT Technical Research Centre of Finland, Espoo.

Physical modelling of ship/ice interaction : Report 2. Parametric model study of ships ramming multi-year ice floes. / Daley, Claude; Kivimaa, Seppo.

Espoo : VTT Technical Research Centre of Finland, 1991. 66 p. (Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports; No. 744).

Research output: Book/ReportReport

TY - BOOK

T1 - Physical modelling of ship/ice interaction

T2 - Report 2. Parametric model study of ships ramming multi-year ice floes

AU - Daley, Claude

AU - Kivimaa, Seppo

PY - 1991

Y1 - 1991

N2 - The report describes the second and final phase of a joint research project between Canada and Finland. The objective of the work was to experimentally investigate the mechanics of a ship ramming a massive ice floe. In the first phase, models of the vessel M.V. Arctic were tested and compared with full scale data. While the model/full scale agreement was encouraging, concern was raised about the influence of ship size, bow form, ice strength scaling and other parameters on the ramming forces and ship hull response. In the second phase, described herein, these questions were addressed by testing a model of a very large vessel (150 000 tonne) and a model of the M.V. Canmar Kigoriak (6 700 tonne). Both models consisted of multiple segments connected to a flexible backbone. Ramming forces and vessel dynamic response were measured. Altogether 107 tests were conducted with these models. The results of the tests are summarised in this report. The main result of the project is the understanding of the ramming process and the ways in which the ship and ice parameters influence the vessel response. The main engineering concern is the maximum bending moment that may occur in the hull girder. It is shown that two separate processes take place during ramming. These can be called initial impact phase and beaching phase. There are cases in which only quasi-static beaching is important, especially for a large ship striking a square ice edge. Dynamically amplified interaction forces of the initial impact phase in some cases may be nearly 50 % larger, and the resulting bending moments may be nearly 100 % larger than those of the quasi-static case. The main factors contributing to dynamics of interaction forces are vessel size, bow form, size of previous imprint and ice strength. Velocity linearly influences force and bending moment, but does not affect the degree of dynamic amplification. The results have implications to both design and operation of Arctic vessels.

AB - The report describes the second and final phase of a joint research project between Canada and Finland. The objective of the work was to experimentally investigate the mechanics of a ship ramming a massive ice floe. In the first phase, models of the vessel M.V. Arctic were tested and compared with full scale data. While the model/full scale agreement was encouraging, concern was raised about the influence of ship size, bow form, ice strength scaling and other parameters on the ramming forces and ship hull response. In the second phase, described herein, these questions were addressed by testing a model of a very large vessel (150 000 tonne) and a model of the M.V. Canmar Kigoriak (6 700 tonne). Both models consisted of multiple segments connected to a flexible backbone. Ramming forces and vessel dynamic response were measured. Altogether 107 tests were conducted with these models. The results of the tests are summarised in this report. The main result of the project is the understanding of the ramming process and the ways in which the ship and ice parameters influence the vessel response. The main engineering concern is the maximum bending moment that may occur in the hull girder. It is shown that two separate processes take place during ramming. These can be called initial impact phase and beaching phase. There are cases in which only quasi-static beaching is important, especially for a large ship striking a square ice edge. Dynamically amplified interaction forces of the initial impact phase in some cases may be nearly 50 % larger, and the resulting bending moments may be nearly 100 % larger than those of the quasi-static case. The main factors contributing to dynamics of interaction forces are vessel size, bow form, size of previous imprint and ice strength. Velocity linearly influences force and bending moment, but does not affect the degree of dynamic amplification. The results have implications to both design and operation of Arctic vessels.

KW - ice

KW - sea ice

KW - icebreakers

KW - ice disintegration

KW - ice loads

KW - ships

KW - interactions

KW - ship hulls

KW - dynamic loads

KW - loads (forces)

KW - ship models

M3 - Report

SN - 951-38-3992-3

T3 - Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports

BT - Physical modelling of ship/ice interaction

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Daley C, Kivimaa S. Physical modelling of ship/ice interaction: Report 2. Parametric model study of ships ramming multi-year ice floes. Espoo: VTT Technical Research Centre of Finland, 1991. 66 p. (Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports; No. 744).