(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)”)