1 Slamming Impact Loads on Large High-Speed Naval Craft ASNE 2008 Sungeun Kim, Derek Novak (ABS)...

1

Slamming Impact Loads on

Large High-Speed Naval Craft

ASNE 2008

Sungeun Kim, Derek Novak (ABS)Hamn-Ching Chen (TAMU)

2

Navy Vessels

Planing Hull High speed vs. length ratio Small high-speed naval craft: PT boats Hydrodynamic lift

Displacement Hull Low speed vs. length ratio Large navy vessels: destroyers, cruisers, battleships Hydrostatic buoyancy

Semi-Planing/Semi-Displacement Hull Intermediate speed vs. length ratio Large high-speed naval craft Partially dynamic & partially static support

9.00.3/ FnorLV

0.3/4.1 LV

4.04.1/ FnorLV

3

Large High-Speed Naval Craft

MONO-1

CAT-2

CAT-1MONO-2

MONO-3

4

Design of High-Speed Naval Craft

Consider all intended operating conditions of the craft specified by Naval Administration

Significant wave height: H1/3

Operating speed: V

Two design conditions in ABS HSNC Guides

Operational Condition: maximum design speed

Survival Condition: 10 knots

Note: not to be less than L/12

Note: to be verified by Naval Administration

HSNC 3-2-2/Table 1

5

Design of High-Speed Naval Craft (cont’d)

Typical Operational Profile of Naval Craft

0

10

20

30

40

50

2 3 4 5 6 7 8

Sea States

V(k

no

ts)

Sea State Hs (m) V(knots)2 0.5 V3 1.25 V4 2.5 V5 4 V6 6 107 9 108 14 10

Design Wave Heights and Speeds

Design Conditions

Operational

Survival

6

Objectives

Current slamming design pressure in HSNC are originally developed for small planing hulls Speed vs. length ratio: Slamming pressure from Heller & Jasper (1960) Vertical acceleration from Savitsky & Brown (1976)

Refine and expand current rules to cover the bottom slamming design pressure for large semi-planing monohulls Speed vs. length ratio Vertical acceleration using LAMP and model test

Update wet-deck slamming design pressure for large high-speed multi-hulls

Validate numerical simulation program LAMP

9.00.3/ FnorLV

0.3/4.1 LV

7

Large Amplitude Motion Program (LAMP)

DARPA 1988 Project • Advanced nonlinear ship motion

simulation to complement linear methods

• Extreme wave loads

Research sponsors• U.S. Navy (ONR, NSWCCD)• U.S. Coast Guard• American Bureau of Shipping• SAIC/MIT

LAMP Development

8

Bottom Slamming Design Pressure for Semi-Planing Monohulls

9

Current: 3-2-2/3.1.1 (Heller & Jasper)

Proposed: Pressure distribution factor FL

Bottom Slamming Design Pressure

)(]70

70][1[

1kPan

BL

Np

cg

bxcg

wwbxx

)(]70

70][1[

1kPaFn

BL

Np L

cg

bxcg

wwbxx

Background: pressure reduction on bow and stern area considering 3D flow effect

Longitudinal Pressure Distribution Factor F_L

0

0.2

0.4

0.6

0.8

1

1.2

0 0.2 0.4 0.6 0.8 1X/L from AP

Fv

10

Vertical Acceleration

One of the most critical driving design factor for high-speed naval craft

Current: 3-2-2/1.1 (Savitsky & Brown)

where

ncg 1/100 highest vertical acceleration

h1/3 1/3 significant wave height

Bw maximum waterline beam

cg deadrise angle at LCG

V design speed (3-2-2/Table 1)

displacement

running trim angle

Note: overestimating for smaller vessels and underestimating for larger vessels

223/1

2 500.112 w

cgw

cg

BV

B

hNn

11

Vertical Acceleration (cont’d)

vcgxx Knn

Proposed ncg:

Proposed Kv

Vertical Acceleration Distribution Factor Kv

0

2

4

6

8

0 0.2 0.4 0.6 0.8 1X/L from AP

Kv

Current

Operation Condition

Survival Condition

23/1

2 500.112 w

cgw

Lcg

VB

B

hCNn

)5.2657.0(*35 LCL

12

Test Vessel: MONO-1

Design Conditions

Large semi-planing monohull with ship length over 100 m

ABS Class based on HSNC Guides

Loading Conditions

13

LAMP Geometry Modeling for MONO-1

Nonlinear Geometry Model for Nonlinear Restoring and Froude-Krylov Forces

Hydro Panel Model for Linear Radiation-Diffraction Forces

14

Vertical Acceleration in Operational Condition

Vertical Acc. at x=90m from AP

-15

-10

-5

0

5

10

15

0 200 400 600 800 1000 1200

t(s)

VC

AA

(m/s

^2)


-10

-5

0

5

10

15

0 200 400 600 800 1000 1200

t(s)

VC

AA

(m/s

^2)


-10

-5

0

5

10

15

0 200 400 600 800 1000 1200

t(s)

VC

AA

(m/s

^2)

Loading Condition: Full Load Departure

• Displacement: 3000 tons

• Speed: 38 knots

• Sea state: SS5 with Hs=4m

Bow

Mid

Stern

15

Vertical Acceleration in Survival Condition


-10

-5

0

5

10

15

0 200 400 600 800 1000 1200

t(s)

VC

AA

(m/s

^2)


-10

-5

0

5

10

15

0 200 400 600 800 1000 1200

t(s)

VC

AA

(m/s

^2)


-10

-5

0

5

10

15

0 200 400 600 800 1000 1200

t(s)

VC

AA

(m/s

^2)

Loading Condition:Full Load Departure

• Displacement: 3000 tons

• Speed: 10 knots


Bow

Mid

Stern

16

Statistical Analysis

Peak Counting

Pick a highest peak between zero-crossings

Threshold: 10% of 1/100 highest peak average

Transient: ignore the first 1/5 of time series

1/100th Highest Peak Average for Vertical Acceleration

Weibull Fitting for Slamming Impact Force

Impact Force Time Series

0.E+00

1.E+05

2.E+05

3.E+05

4.E+05

5.E+05

350 360 370 380 390 400t(s)

w(N

/m)

LAMP

Threshold

Peak

17

1/100th Vertical Acceleration

Operational Condition

• Full Load Departure: 3000 tons

• Speed: 38knots



• Full Load Arrival: 2900 tons

• Ship Speed: 40 knots

• Sea State: SS5 with Hs=4m

1/100th Vertical Accel at Full Load Departure

0

0.5

1

1.5

2

0 0.2 0.4 0.6 0.8 1

X from AP

VA

CC

(g

)

LAMP

Model Test

Proposed

1/100th Vertical Accel at Full Load Arrival

0

0.5

1

1.5

2

0 0.2 0.4 0.6 0.8 1

X from AP

VA

CC

(g

)

LAMP

Proposed

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1/100th Vertical Acceleration


• Full Load Minimum: 2800 tons

• Ship Speed: 42 knots

• Sea State: SS5 with Hs=4m

Survival Condition

• Full load departure: 3000 tons

• Speed: 10 knots


1/100th Vertical Accel at Full Load Minimum

0

0.5

1

1.5

2

0 0.2 0.4 0.6 0.8 1

X from AP

VA

CC

(g

)

LAMP

Proposed

1/100th Vertical Acc. at Full Load Survival

0

0.5

1

1.5

2

0 0.2 0.4 0.6 0.8 1

X from AP

VA

CC

(g

)

LAMP

Proposed

19

Impact Force in Operational Condition

Sectional Cut at x=20m from AP

-4

-2

0

2

4

6

8

10

-10 -8 -6 -4 -2 0 2 4 6 8 10

Sectional Cut at x=90m from AP

-4

-2

0

2

4

6

8

10

-10 -8 -6 -4 -2 0 2 4 6 8 10

x=20 from AP

0

500

1000

1500

0 200 400 600 800 1000 1200t(s)

w(k

N/m

)LAMPCurrentProposed

x=90 from AP

0

500

1000

1500

0 200 400 600 800 1000 1200t(s)

w(k

N/m

)

LAMPCurrentProposed

20

Impact Force in Survival Condition

Cut at x=10m from AP

-4

-2

0

2

4

6

8

10

-10 -8 -6 -4 -2 0 2 4 6 8 10

Cut at x=90m from AP

-4

-2

0

2

4

6

8

10

-10 -8 -6 -4 -2 0 2 4 6 8 10

x=90 from AP

0

500

1000

1500

0 200 400 600 800 1000 1200

t(s)

w(k

N/m

)

LAMPCurrentProposed

x=20 from AP

0

500

1000

1500

0 200 400 600 800 1000 1200

t(s)

w(k

N/m

)

LAMPCurrentProposed

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Impact Force in Operational Condition

x=90m from AP

0.0001

0.001

0.01

0.1

1

0 500 1000 1500

w(kN/m)

Q

LAMPWeibullCurrentProposed

x=20m from AP

0.0001

0.001

0.01

0.1

1

0 500 1000 1500

w(kN/m)

Q

LAMPWeibullCurrentProposed

22

Design Pressure: Operational at Full Load Depart.

Bottom Slamming Pressure:

Full Load Departure at Hs=4m and V=38 knots

Sectional Impact Force: (Heller & Jasper)

)/(6/ mNpBw

Bottom Slamming Pressure at Full Load Departure

0

100

200

300

400

500

0 0.2 0.4 0.6 0.8 1

X from AP

P (

kPa)

Current Proposed Design

Vertical Imapct Force at Full Load Departure

0

500

1000

1500

0 0.2 0.4 0.6 0.8 1

X from AP

F(k

N/m

)

Current

Proposed

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Design Pressure: Operational at Full Load Arrival


Full Load Arrival at Hs=4m and V=40 knots


)/(6/ mNpBw

Bottom Slamming Pressure at Full Load Arrival

0

100

200

300

400

500

0 0.2 0.4 0.6 0.8 1

X from AP

P (

kPa)


Vertical Imapct Force at Full Load Arrival

0

500

1000

1500

0 0.2 0.4 0.6 0.8 1

X from AP

F(k

N/m

)

Current

Proposed

24

Design Pressure: Operational at Full Load Min.


Full Load Minimum at Hs=4m and V=42 knots


)/(6/ mNpBw

Vertical Imapct Force at Full Load Minimum

0

500

1000

1500

0 0.2 0.4 0.6 0.8 1

X from AP

F(k

N/m

)Current

Proposed

Bottom Slamming Pressure at Full Load Minimum

0

100

200

300

400

500

0 0.2 0.4 0.6 0.8 1

X from AP

P (

kPa)


25

Design Pressure: Survival at Full Load Depart.


Full Load Departure at Hs=9m and V=10 knots


)/(6/ mNpBw

Bottom Slamming Pressure at Survival condition

0

100

200

300

400

500

0 0.2 0.4 0.6 0.8 1

X from AP

P (

kPa)


Vertical Imapct Force at Survival condition

0

500

1000

1500

0 0.2 0.4 0.6 0.8 1

X from AP

w(k

N/m

)

Current

Proposed

26

Wet-Deck Slamming Pressure for Multi-Hulls

27

Current: HSNC 3-2-2/3.5

Proposed

where

FI pressure distribution factor

VI relative impact velocity

ha distance from waterline to deck

H1/3 significant wave height

Wet-Deck Slamming Design Pressure

)/()/85.01(30 23/1 mkNhhVVFFp aIIDwd

)/()/5.01(30 23/1 mkNhhVVFFp aIIDwd

Wet Deck Pressure Distribution Factor F_I

0

0.5

1

1.5

2

0 0.2 0.4 0.6 0.8 1

X from AP

F_I

CurrentProposed: OperationalProposed: Survival

28

Current Wet-Deck Design Pressure

Proposed Wet-Deck Design Pressure

Wet-Deck Design Pressure (cont’d)

Proposed Wet Deck Design Pressure

0

50

100

150

200

0 0.2 0.4 0.6 0.8 1x/L

p_w

d (

kPa)

Operational

Survival

Current Wet Deck Design Pressure

0

50

100

150

200

0 0.2 0.4 0.6 0.8 1

x/L

p_w

d (

kPa)

Operational

Survival

29

Test Vessel: CAT-1

High-speed wave-piercing catamaran

Length: LWL=73m

Speed: 40knots

ABS Class

Hull damage was reported, likely due to wet-deck slamming impact loads

30

LAMP Simulation for Wet-Deck Slamming

LAMP simulation with wet-deck option

2D wedge impact theory (Ge, Faltinsen, Moan 2005) on longitudinal cuts

Require smaller time step

Require supplemental pitch damping model

LMPRES to extract wet-deck slamming pressure

PLMPRES to generate nodal pressure time series

2 13 1 2

dc VF c V B c B

dt t

31

Supplemental Pitch Damping in LAMP

Pitch Motion of X-Craft

-10

-5

0

5

10

0 10 20 30 40 50t(s)

pit

ch

(de

g)

no pitch dampingsuppliment pitch damping

2 55 5 5 5 5

5

* * *v

ME v KL v KQv

Supplemental pitch damping model in LAMP

Based on the model test measurements of CAT-1, additional pitch damping is considered for pitch motion simulation

32

Vertical Acceleration at Forward P1

-8

-4

0

4

8

12

0 5 10 15 20

t(s)

VA

CC

(m/s

^2)

Relative Motion in Model Test Condition

Relative Motion at P1 in Regular Waves

-2

0

2

4

6

8

10

0 5 10 15 20t(s)

Rel

ativ

e m

oti

on

(m

)

Relative Vertical Motion

Vertical Acceleration

33

Wet-Deck Slamming Pressure in Model Test Condition

Wet-Deck Slamming Pressure

0

10000

20000

30000

40000

7 8 8 9 9 10 10t(s)

P(P

a)

P1

P2

P3

P4

Wet-Deck Slamming Pressure at P3

0

10000

20000

30000

40000

0 5 10 15 20 25t(s)

p(P

a)

P1

P2P3P4

34

Wet-Deck Slamming Pressure in Survival Condition


0

50000

100000

150000

200000

250000

0 100 200 300 400 500 600 700 800 900

t(s)p

(Pa)

LAMP

LAMP

Current

Proposed


0

50000

100000

150000

200000

250000

0 100 200 300 400 500 600 700 800 900

t(s)

p(P

a)

LAMP

LAMP

Current

Proposed

35


Wet-Deck Slamming Pressure at x=0.9L

0

50000

100000

150000

200000

250000

0 100 200 300 400 500 600 700 800 900

t(s)p

(Pa

)

LAMP

Current

Proposed

LMAP


0

50000

100000

150000

200000

0 100 200 300 400 500 600 700 800 900

t(s)

p(P

a)

LAMP

LAMP

Current

Proposed

x=0.9L from AP

x=0.8L from AP

36



0

50000

100000

150000

200000

0 100 200 300 400 500 600 700 800 900

t(s)

p(P

a)

LAMP

Current

Proposed


0

50000

100000

150000

200000

0 100 200 300 400 500 600 700 800 900

t(s)

p(P

a)

LAMP

Current

Proposed

x=0.6L from AP

x=0.2L from AP

37



0.0001

0.0010

0.0100

0.1000

1.0000

0 50000 100000 150000 200000 250000

p(Pa)Q

LAMP

Weibull

Current

Proposed


0.0001

0.0010

0.0100

0.1000

1.0000

0 50000 100000 150000 200000 250000

p(Pa)

Q

LAMP

Weibull

Current

Proposed

38

Wet-Deck Slamming Pressure in Operational Condition


0

50000

100000

150000

200000

250000

0 100 200 300 400 500 600 700 800 900

t(s)p

(Pa)

LAMP

LAMP

Current

Proposed


0

50000

100000

150000

200000

250000

0 100 200 300 400 500 600 700 800 900

t(s)

p(P

a)

LAMP

LAMP

Current

Proposed

39


Wet-Deck Slamming Pressure at x=0.9L from AP

0

50000

100000

150000

200000

250000

0 100 200 300 400 500 600 700 800 900

t(s)

p(P

a)

LAMP

LAMP

Current

Proposed

Wet-Deck Slamming Pressure at x=0.8L fromAP

0

50000

100000

150000

200000

250000

0 100 200 300 400 500 600 700 800 900

t(s)

p(P

a)

LAMP

LAMP

Current

Proposed

x=0.9L from AP

x=0.8L from AP

40



0

50000

100000

150000

200000

0 100 200 300 400 500 600 700 800 900

t(s)

p(P

a)

LAMP

LAMP

Current

Proposed


0

50000

100000

150000

200000

0 100 200 300 400 500 600 700 800 900

t(s)

p(P

a)LAMP

LAMP

Current

Proposed

x=0.6L from AP

x=0.2L from AP

41

Wet-Deck Slamming in Operational Condition


0.0001

0.0010

0.0100

0.1000

1.0000

0 50000 100000 150000 200000

p(Pa)Q

LAMP

Weibull

Current

Proposed


0.0001

0.0010

0.0100

0.1000

1.0000

0 50000 100000 150000 200000

p(Pa)

Q

LAMP

Weibull

Current

Proposed

42

FANS (Finite Analytic Navier-Stokes) Code

CFD solver developed by Texas A&M

Unsteady incompressible/compressible two-phase flow solver

Multi-block solver using overset grids

Nonlinear free-surface capturing scheme using level-set method

FANS developments in ABS-TAMU

LNG sloshing impact pressure

Wet-deck slamming impact pressure

Bow/stern slamming and green sea loads

43

FANS Modeling of CAT-1: Overset Grid

25 blocks, 16 processors, 2.16 million grid points for half-domain

44

FANS Wet-deck Slamming of CAT-1

45

Summary

Bottom slamming pressure for monohulls Vertical acceleration is one of the most driving design factor

for high-speed naval craft. Vertical acceleration has been revised to cover large semi-

planing naval craft based on numerical simulation and model test

Slamming design pressure has been validated with existing design of high-speed naval craft

Wet-deck slamming pressure for multi-hulls Numerical simulation for wet-deck slamming has been

performed in time domain using LAMP Wet-deck design pressure is revised based on numerical

simulation. Survival condition is found to be a governing condition for wet-

deck slamming pressure

46

On-going/Future Projects in ABS-SAIC-TAMU

Guide for direct analysis procedure Wave-induced design loads Whipping loads for monohulls Wet-deck slamming loads for multi-hulls

Guide for slamming model test procedure Vertical acceleration Local vs. panel pressure Statistic analysis for design pressure

Software validation of wet-deck slamming Numerical simulation using LAMP/FANS code Model test/Full scale measurements

1 Slamming Impact Loads on Large High-Speed Naval Craft ASNE 2008 Sungeun Kim, Derek Novak (ABS)...

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Transcript of 1 Slamming Impact Loads on Large High-Speed Naval Craft ASNE 2008 Sungeun Kim, Derek Novak (ABS)...