1 slamming impact loads on large high-speed naval craft asne 2008 sungeun kim, derek novak (abs)...
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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)
Vertical Acc. at x=50m from AP
-10
-5
0
5
10
15
0 200 400 600 800 1000 1200
t(s)
VC
AA
(m/s
^2)
Vertical Acc. at x=10m from AP
-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
Vertical Acc. at x=90m from AP
-10
-5
0
5
10
15
0 200 400 600 800 1000 1200
t(s)
VC
AA
(m/s
^2)
Vertical Acc. at x=50m from AP
-10
-5
0
5
10
15
0 200 400 600 800 1000 1200
t(s)
VC
AA
(m/s
^2)
Vertical Acc. at x=50m from AP
-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
• Sea state: SS8 with Hs=9m
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
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1/100th Vertical Acceleration
Operational Condition
• Full Load Departure: 3000 tons
• Speed: 38knots
• Sea state: SS5 with Hs=4m
Operational Condition
• 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
18
1/100th Vertical Acceleration
Operational Condition
• 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
• Sea state: SS8 with Hs=9m
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
21
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
23
Design Pressure: Operational at Full Load Arrival
Bottom Slamming Pressure:
Full Load Arrival at Hs=4m and V=40 knots
Sectional Impact Force: (Heller & Jasper)
)/(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)
Current Proposed Design
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.
Bottom Slamming Pressure:
Full Load Minimum at Hs=4m and V=42 knots
Sectional Impact Force: (Heller & Jasper)
)/(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)
Current Proposed Design
25
Design Pressure: Survival at Full Load Depart.
Bottom Slamming Pressure:
Full Load Departure at Hs=9m and V=10 knots
Sectional Impact Force: (Heller & Jasper)
)/(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)
Current Proposed Design
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
Wet-Deck Slamming Pressure at P1
0
50000
100000
150000
200000
250000
0 100 200 300 400 500 600 700 800 900
t(s)p
(Pa)
LAMP
LAMP
Current
Proposed
Wet-Deck Slamming Pressure at P3
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 in Survival Condition
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
Wet-Deck Slamming Pressure at x=0.8L
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
Wet-Deck Slamming Pressure in Survival Condition
Wet-Deck Slamming Pressure at x=0.6L
0
50000
100000
150000
200000
0 100 200 300 400 500 600 700 800 900
t(s)
p(P
a)
LAMP
Current
Proposed
Wet-Deck Slamming Pressure at x=0.2L
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
Wet-Deck Slamming Pressure in Survival Condition
Wet-Deck Slamming Pressure at P1
0.0001
0.0010
0.0100
0.1000
1.0000
0 50000 100000 150000 200000 250000
p(Pa)Q
LAMP
Weibull
Current
Proposed
Wet-Deck Slamming Pressure at P3
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
Wet-Deck Slamming Pressure at P1
0
50000
100000
150000
200000
250000
0 100 200 300 400 500 600 700 800 900
t(s)p
(Pa)
LAMP
LAMP
Current
Proposed
Wet-Deck Slamming Pressure at P3
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 in Operational Condition
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
Wet-Deck Slamming Pressure in Operational Condition
Wet-Deck Slamming Pressure at x=0.6L from AP
0
50000
100000
150000
200000
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=0.2L from AP
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
Wet-Deck Slamming Pressure at P1
0.0001
0.0010
0.0100
0.1000
1.0000
0 50000 100000 150000 200000
p(Pa)Q
LAMP
Weibull
Current
Proposed
Wet-Deck Slamming Pressure at P3
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