A compliant cylindrical structure has been built and tested in a series of model tests in ice in the Large Ice Model Basin at HSVA. The structure's stiffness in ice plane is higher in ice drift direction than crosswise, enabling the model to vibrate in different geometrical oscillation patterns. In total, four ice sheets have been used to perform tests in different ice thickness, covering a wide range of ice drift velocities between 0.005 and 0.15 m/s in model scale. Several events of ice-induced vibrations were observed throughout the test campaign. Oscillations are found to reach different types of beginning steady states, depending on ice drift velocity and ice thickness. Dynamic amplification of structural response in ice plane as well as ratio of static and dynamic forces is highly dependent on the type of vibration. While the dynamic amplification is highest when the ice load's frequency equals the first natural frequency of the structure, the highest dynamic forces occur when the crushing frequency is an integer fraction of the natural frequency. The paper describes the design of the test setup, instrumentation and calibration, performance and analysis of conducted tests, and general findings.

References

References
1.
Määttänen
,
M.
,
1975
, “
On Conditions for the Rise of Self-Excited Ice-Induced Autonomous Oscillations in Slender Marine Pile Structures
,” Research Report 25, Finnish-Swedish Winter Navigation Board, Finland, Research Report 25.
2.
Kärnä
,
T.
, and
Turunen
,
R.
,
1990
, “
A Straightforward Technique for Analysing Structural Response to Dynamic Ice Action
,”
9th OMAE Conference
, Houston, TX, pp.
135
142
.
3.
Eranti
,
E.
,
1992
, “
Dynamic Ice-Structure Interaction: Theory and Applications
,”
Ph.D. thesis
, VTT Technical Research Centre of Finland, Helsinki, Finland.
4.
Peyton
,
H. R.
,
1966
, “
Sea Ice Strength
,” Final Report for the Navy Office of Naval Research, Geophysical Institute, University of Alaska, Fairbanks, AK,
Contract Nr 2601(01)
.
5.
Määttänen
,
M.
,
2014
, “
Dynamic Ice Structure Interaction—Evolution in 50 Years
,”
22nd IAHR International Symposium on Ice
, Singapore, Paper No. 1134.
6.
Kärnä
,
T.
,
Andersen
,
H.
,
Gürtner
,
A.
,
Metrikine
,
A.
,
Sodhi
,
D.
,
Loo
,
M.
,
Kuiper
,
G.
,
Gibson
,
R.
,
Fenz
,
D.
,
Muggeridge
,
K.
,
Wallenburg
,
C.
,
Wu
,
J.-F.
, and
Jefferies
,
M.
,
2013
, “
Ice-Induced Vibrations of Offshore Structures—Looking Beyond ISO 19906
,”
22nd International Conference on Port and Ocean Engineering Under Arctic Conditions
, Espoo, Finland, Paper No. 226.
7.
Schwarz
,
J.
, and
Jochmann
,
P.
,
2001
, “
Ice Force Measurements Within the LOLEIF Project
,” 16th Int. Conf. Port and Ocean Eng. Under Arctic Cond.
(POAC'01)
, Ottawa, Canada, Vol. 2., pp. 669–680.
8.
Barker
,
A.
,
Timco
,
G.
,
Gravesen
,
H.
, and
Vølund
,
P.
,
2005
, “
Ice Loading on Danish Wind Turbines. Part 1: Dynamic Model Tests
,”
Cold Reg. Sci. Technol.
,
41
(
1
), pp.
1
23
.
9.
Cornett
,
A. M.
, and
Timco
,
G.
,
1998
, “
Ice Loads on Elastic Model of the Molikpaq
,”
Appl. Ocean Res.
,
20
(
2
), pp.
105
118
.
10.
Määttänen
,
M.
,
1979
, “
Laboratory Tests for Dynamic Ice-Structure Interaction
,”
Conference on Port and Ocean Engineering Under Arctic Conditions
, Trondheim, Norway, Vol. 2, pp. 1139–1154.
11.
Onken
,
G.
,
Evers
,
K.-U.
,
Haase
,
A.
, and
Jochmann
,
P.
,
2013
, “
Ice Model Tests With a Cylindrical Structure to Investigate Dynamic Ice-Structure Interactions
,”
22nd International POAC Conference
, Espoo, Finland, Paper No. 55.
12.
Fransson
,
L.
, and
Stenman
,
U.
,
2003
, “
Mechanical Properties of Ice at Norströmsgrund, Tests 2003
,”
STRICE
Consortium, Hamburg, Germany, STRICE Deliverable D-4.3.3.
13.
Hendrikse
,
H.
,
Metrikine
,
A.
, and
Evers
,
K.-U.
,
2012
, “
A Method to Measure the Added Mass and Added Damping in Dynamic Ice-Structure Interaction: Deciphering Ice-Induced Vibrations, Part 3
,”
21st IAHR International Symposium on Ice
, Dalian, China, pp. 972–984.
14.
ISO
,
2010
, “
Petroleum and Natural Gas Industries—Arctic Offshore Structures
,” International Organization for Standardization, Geneva, Standard No. ISO 19906:2010.
15.
Kärnä
,
T.
, and
Järvinen
,
E.
,
1999
, “
Symmetric and Asymmetric Flaking Processes
,”
15th International Conference on Port and Ocean Engineering Under Arctic Conditions
, Helsinki, Finland, Aug. 23–27, pp.
988
1000
.
16.
Yap
,
K. T.
, and
Palmer
,
A. C.
,
2013
, “
A Model Test on Ice-Induced Vibrations: Structure Response Characteristics and Scaling of the Lock-In Phenomenon
,”
22nd International Conference on Port and Ocean Engineering Under Arctic Conditions
, Espoo, Finland, Paper No. 106.
17.
Bjerkas
,
M.
,
Meese
,
A.
, and
Alsos
,
H. S.
,
2013
, “
Ice Induced Vibrations—Observations of a Full Scale Lock-In Event
,”
23rd International Offshore and Polar Engineering Conference
, Anchorage, AK, Paper No. ISOPE-I-13-194.
18.
Bjerkas
,
M.
, and
Skiple
,
A.
,
2005
, “
Occurrence of Continuous and Intermittent Crushing During Ice-Structure Interaction
,”
18th International Conference on Port and Ocean Engineering Under Arctic Conditions
, Potsdam, NY, Vol. 3, pp. 1131–1140.
19.
Kry
,
P. R.
,
1978
, “
A Statistical Prediction of Effective Ice Crushing Stresses on Wide Structures
,”
IAHR Ice Symposium
, Lulea, Sweden, pp. 7–9.
20.
Kärnä
,
T.
,
1994
, “
Steady-State Vibrations of Offshore Structures
,”
Hydrotechnical Construction
,
28
(
8
), pp.
446
453
.
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