(A) Without wave (B) Regular wave
Ship in small ice floes + regular waves
*The test is repeated twice for the open water test and three mes for small ice floes in one test condi on to verify the accuracy of measurements.
Resistance
2.0
1.5
1.0
0.5
0.0
Resis
tanc
e Fx
[N]
0.0 0.1 0.2 0.3 0.4 0.5
Open water (Calm)Small ice floes (Calm)
Ice resistance
Carriage speed [m/s]
Open water (Wave)Small ice floes (Wave)
2.0
1.5
1.0
0.5
0.0
Resis
tanc
e Fx
[N]
0.0 0.1 0.2 0.3 0.4 0.5Carriage speed [m/s]
Ice resistance
Ship in small ice floes + regular wavesComparison of ice resistance
0.0 0.1 0.2 0.3 0.4 0.5
Carriage speed [m/s]
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Calm waterWave (H = 0.02 m)Linear line (Calm)Linear line (Wave)Kashiteljan,1968(ice = 78 %, channel width = 2.0 m)
Without wave
Regular wave
Ice
resis
tanc
e Rx
[N]
Kashiteljan,1968
Reason??-> Ice mo on?(a enuma on, eleva on)-> Wave a enua on
Ice floes = 500
Laser sensorWave gauge
2D tank: Osaka University
Ri = 5 cmHi = 1cm = 910 kg/m3
Regular waveHw = 1, 2, 3 and 4 cmLw = 0.3, 0.5, 1.0, 1.5 m
Small ice floes in regular waves
Regular wave
Top view
Wave gauge(Ice height)
Laser sensor (ice height)
Accelerometer (ice mo on)
Wav
e g
ener
ator
CH01 CH02CH03 CH04
1 m
Wave generator
Side view
Ice floes (PP) 60 cm
45 cm
30 cm
Regular wave
Wave gauge
Video camera 1
5cm Hi = 1cm = 910 kg/m3500 pieces
Polypropylene ice
Hw = 1, 2, 3 and 4 cmLw = 0.3, 0.5, 1.0, 1.5 m
(Ice concentra on)
CH05
8.5 m
1 m1 m 1.5 m
1.5 m 2.0 m
Rela onship between Wave H/ice H and Ice C
L = 2.0 m, H = 4.0 cm L = 1.5 m, H = 3.0 cm L = 1.0 m, H = 2.0 cm L = 0.5 m, H = 1.0 cm
(A) Wave Height / Wave Length = 1/50
Wave lenght, Height
50 60 70 80 90 100Ice concentra on (%)
0.0
0.5
1.0
1.5
Ice
H/W
ave
H
L = 1.0 m, H = 4.0 cm
L = 0.5 m, H = 2.0 cm L = 1.0 m, H = 3.0 cm
L = 0.4 m, H = 2.0 cm L = 0.3 m, H = 2.0 cm L = 0.3 m, H = 0.5 cm
Wave lenght, Height
50 60 70 80 90 100Ice concentra on (%)
0.0
0.5
1.0
1.5
Ice
H/W
ave
H
(Wave a enua on)
(B) Wave Height / Wave Length = 1/20 -1/33.3
Ice Rules
IACS Polar Class Rules (URI)Arctic Rule Systems Sub-Arctic Rule Systems
ASPPR RulesRussian Rules
Class Rules
Bal c RulesClass Rules
IACS Polar Rules
Comparing Ice Class Rules 1. Design scenarios 2. Ice mechanics concepts (Ice load model) 3. Strength formula ons (Elas c, Plas c, Ice Strengthened Hull Areas) 4. Opera onal 5. Parameters considered
Ice class refers to a nota on assigned by a classifica on society or a na onal authority to denote the addi onal level of strengthening as well as other arrangements that enable a ship to navigate through sea ice. Some ice classes also have requirements for the ice-going performance of the vessel (from Wikipedia).
1. Power requirement 2. Hull strength 3. Propulsion machinery
Ref: Daley Claude, 2014 ,Ice Class Rules (From Wikipedia)
Ice ClassRS (Rules 2008) Arc9 Arc8 Arc7 Arc6 Arc5 Arc4RS (Rules 1995) - ULA - UL L1IACS POLAR PC1 PC2 PC3 PC4 PC5 PC6 PC7CASPPR, 1995 CAC2 CAC3 CAC4 A BABS A4 A3 A2 А1 А0DNV POLAR-20 POLAR-15 POLAR-10 ICE-10 ICE-05 ICE-15 ICE-1А ICE-1АLR AC2 AC1.5 AC1 1AS 1AGL (Old Rules) Arc3 Arc 2 Arc1 Е4 Е3FSICR - - - 1А Super 1АBV - - - 1A Super 1АNKK - - - 1A Super 1AKR - - - ISS IS1CCS - - - B1 B1RINA - - - 1AS 1A
Comparison of Ice class rules
Data from1) Daley Claude, 2014 ,Ice Class Rules (From Wikipedia)2) Northern Sea Route Handbook B_E, 2006, The Japan Associa on of Marine Safety 3) lecture note of DESIGN OF ICE-GOING SHIPS, 2007, Prof. Kaj Riska, NTNU
0.0e+00 6.0e+00 1.2e+01 1.8e+01 2.4e+01 3.0e+01 3.6e+01 4.2e+01 4.8e+01 5.4e+01 6.0e+01
Equivalent Von Mises Stress
X
Y
ZZ
X
Y
Structural response of s ffened panel under ice force
Fig.2 Equivalence Von Mises of s ffened panel (ice thickness = 1.0m).
Contact area = 0.529m2 (Triangle)Max. Stress = 73.77 MPa
50 6052 54 56 58
12345
0Time [s]
Forc
e [E
+06
N]
Area 01 - Area 08
S ffner S ffnerS ffner S ffnerS ffner S ffner
50.00 [m]
1.0×
0.3m
48.00 48.50 49.00 49.50
Ice pressure area for FEM Contact area
Waterline
Fig.1 Ice pressured area and me history ac ng on the s ffened panel (Ice thickness = 0.5m, ship speed = 5.0 m/s).
Junji Sawamura, Numerical study on the local ice force distribu on in the ice breaking and ice submerging for the ship maneuvering in level ice, The proceeding of the 27th Asian-Pacific Technical Exchange and Advisory Mee ng on Marine Structures, 2013, pp.280-287
Ship local/global responseIce force and ice puressure of 2D ship model
0 1 2 3 4 5
30
20
10
0
-10
Progress distance [m]
Stre
ss [u
]
-20
10 20 40 60Time [s]30 50
press area (1st )press area (2nd )press area (3rd)
Pres
sure
d ar
ea [i
n2]
0
1.0
2.0
3.0
1.5
0.5
2.5
- Ship speed = 0.04 m/s - Ice thickness = 0.02 m- Ice length = 0.10 m
Model ship0.04m/s
10 20 40 60Time [s]
30 50-1
0
1
2
3
5
4
Surg
e fo
rce
[N]
x force (1st )x force (2nd )x force (3rd)
Junji Sawamura, Shinji Kioka and Akihisa Konno, Experimental and numerical inves ga on on ice submerging for icebreaker with 2D model test using synthe c ice, Proceedings of the 23nd Interna onal Conference on Port and Ocean Engineering under Arc c Condi ons, 2015, No.34.
Ice floeWater line
Comparison of Fa gue Damage in Sea ice (Ship side hull)
Published bySuyuthi. A, et al. (2013)Han and Sawamura (2016)Han and Sawamura (2017)
Han and Sawamura (2018)
Sea areaBal c SeaBal c SeaAntarc c Sea (Worby et al.,2008)Bal c Sea
Ice condi onPack ice + Level ice + Ridge iceLevel icePack ice
Level ice + Ridge ice
Fa gue damege5.836 × 10-45.617 × 10-31.788 × 10-4
4.270× 10-2
Yue Han and Junji Sawamura, Calcula on of Ship Hull Fa gue Damage caused by Local Ice Loads in Ridged Ice Fields, The proceeding of 28th Interna onal Offshore and Polar Engineering Conference, 2018, pp. 1755-1762
Ship local hull response
Fig. Model of ice load acting on the transverse frames and structures.
L
L
L
h
shell plate
s
Load patch
w = s
h
shell plate
s
Frame spacing
p: ice pressure as given in 4.2.2 [Mpa]s: fram spacing [m]h: height of load area as given in 4.2.1 [m]
Z = p · s · h · lmt · y
10 6
l : span of the frames [m]mt: 7m0/(7-5h/l)y: yield stress as in 4.3.2 [N/mm2]
(Ref: THE STRUCTURAL DESIGN AND ENGINE OUTPUT REQUIRED OF HIPS FOR NAVIGATION IN ICE “FINNISH-SWEDISH ICE CLASS RULES (FSICR)”)