Hydrodynamic effects in ship collisions are usually considered by increased inertia force in the form of the equivalent added mass. It is necessary to reasonably estimate the equivalent added mass to calculate energy absorbed by ships in collisions. In this paper, motion equations in the horizontal plane for the struck rigid ship are first established considering hydrodynamic effects in the form of added mass, linear, and quadratic damping. The equivalent added mass are obtained in three ways and analyzed. It is shown that the equivalent added mass for the sway motion depends on not only the duration of collision impact, impact force, but also the collision position, while the equivalent added mass for the yaw motion could be assumed to be independent of the collision position. In addition, a simple formula is proposed to relate the equivalent added mass for part of the vessel to that of the whole vessel, provided that the underwater area of the transverse section is known. As a consequence, it is possible to estimate rigid hull girder responses based on the simplified methodology, which could be used in design and probabilistic collision analyses. In the end, the hull girder responses are estimated considering both a flexible and rigid vessel. Comparisons are made between rigid and flexible hull girder responses.

References

References
1.
Wang
,
G.
,
Spencer
,
J.
, and
Chen
,
Y.
,
2002
, “
Assessment of a Ship’s Performance in Accidents
,”
Mar. Struct.
,
15
(4–5), pp.
313
333
.10.1016/S0951-8339(02)00017-5
2.
ISSC
,
2003
, “
Collision and Grounding
,”
15th International Ship and Offshore Structures Congress
,
San Diego
,
CA
.
3.
ISSC
,
2006
, “
Collision and Grounding
,”
16th International Ship and Offshore Structures Congress
,
Southampton
,
UK
.
4.
Samuelides
,
M. S.
,
2009
, “
Design Against Collision: Half a Century of Research
,”
International Marine Design Conference
,
Trondheim
,
Norway
.
5.
Pedersen
,
P. T.
,
1995
, “
Collision and Grounding Mechanics
,”
WEMT, Ship Safety and Protection of the Environment From a Technical Point of View
,
The Danish Society of Naval Architects and Marine Engineers
.
6.
Petersen
,
M. J.
,
1982
, “
Dynamics of Ship Collisions
,”
Ocean Eng.
,
9
(
4
), pp.
295
329
.10.1016/0029-8018(82)90026-9
7.
Brown
,
2002
, “
Collision Scenarios and Probabilistic Collision Damage
,”
Mar. Struct.
,
15
(4–5), pp.
335
364
.10.1016/S0951-8339(02)00007-2
8.
Pedersen
,
P. T.
, and
Zhang
,
S.
,
1998
, “
On Impact Mechanics in Ship Collisions
,”
Mar. Struct.
,
11
(10), pp.
429
449
.10.1016/S0951-8339(99)00002-7
9.
Petersen
,
M. J.
, and
Pedersen
,
P. T.
,
1981
, “
Collision Between Ships and Offshore Platforms
,”
Offshore Technology Conference
,
Houston
,
TX
, Paper No. OTC 4134.
10.
Motora
,
S.
,
1960
, “
On the Measurement of Added Mass and Added Moment of Inertia of Ships in Steering Motion
,”
1st Symposium on Ship Maneuverability
,
David Taylor Naval Ship Research and Development Center
,
Washington, DC
, pp.
241
274
.
11.
Minorsky
,
V. U.
,
1959
, “
An Analysis of Ship Collision With Reference to Protection of Nuclear Powered Plants
,”
J. Ship Res.
,
3
, pp.
1
4
.
12.
Motora
,
S.
,
Fujino
,
M.
,
Suguira
,
M.
, and
Sugita
,
M.
,
1971
, “
Equivalent Added Mass of Ships in Collisions
,”
Sel. Pap. J. Soc. Naval Archit. Jpn.
,
7
, pp.
138
148
.
13.
Reckling
,
K. A.
,
1981
, “
Overall Structural Response of a Ship Struck in a Collision
,”
Extreme Loads Response Symposium
,
Arlington
,
VA
.
14.
Pedersen
,
P. T.
, and
Li
,
Y.
,
2009
, “
On the Global Ship Hull Bending Energy in Ship Collisions
,”
Mar. Struct.
,
22
(
1
), pp.
2
11
.10.1016/j.marstruc.2008.06.005
15.
Amdahl
,
J.
,
2009
, private communication.
16.
WAMIT
, “
WAMIT User Manual
,” www.wamit.com
You do not currently have access to this content.