The gravity-type fish cage is extensively applied with the increasing demand for fishery products. The flotation ring is its main load-bearing component and supports the whole cage. So it is essential to study the hydroelasticity of the flotation ring for the safety of a fish cage. An analytical method is proposed to study the elastic deformation of a simplified flotation ring subjected to water waves. The equations governing in-plane deformations are obtained according to curved beam theory, in which the modal superposition method is used to represent the in-plane deformation of an element of the ring. Then, the motion equations of the ring are built up coupled with deformation equations. The correlation between the predicted results and the experimental data is acceptable to validate the numerical modeling. Then the effect of Young’s module, radius of the ring, and wave conditions on elastic responses is discussed in terms of the prototype scale of a flotation ring. It is concluded that the deformations over the ring in the direction of waves’ propagation are the largest, and that the mooring point in the head-on direction of the waves is critical for reliability of the ring. Large deformations of the flotation ring may induce the failure of the fish cage when the storm covers it. So more attention to the hydroelasticity of the flotation ring should be paid in the design for a fish cage.

1.
Fredriksson
,
D. W.
, 2001. “
Open Ocean Fish Cage and Mooring System Dynamics
,” Ph.D. thesis, University of New Hampshire, Durham.
2.
Fredriksson
,
D. W.
,
Swift
,
M. R.
,
Irish
,
J. D.
,
Tsukrov
,
I.
, and
Celikkol
,
B.
, 2003, “
Fish Cage and Mooring System Dynamics Using Physical and Numerical Models With Field Measurements
,”
Aquacultural Eng.
0144-8609,
27
, pp.
117
146
.
3.
Huang
,
C. C.
,
Tang
,
H. J.
, and
Liu
,
J. Y.
, 2006, “
Dynamical Analysis of Net Cage Structures for Marine Aquaculture: Numerical Simulation and Model Testing
,”
Aquacultural Eng.
0144-8609,
35
, pp.
258
270
.
4.
Li
,
Y. C.
,
Zhao
,
Y. P.
,
Gui
,
F. K.
, and
Teng
,
B.
, 2006, “
Numerical Simulation of the Hydrodynamic Behavior of Submerged Plane Nets in Current
,”
Ocean Eng.
0029-8018,
33
(
17–18
), pp.
2352
2368
.
5.
Li
,
Y. C.
,
Zhao
,
Y. P.
,
Gui
,
F. K.
, and
Teng
,
B.
, 2006, “
Numerical Simulation of the Influences of Sinker Weight on the Deformation and Load of Net of Gravity Sea Cage in Uniform Flow
,”
Acta Oceanologica Sinica
,
25
(
3
), pp.
1
18
.
6.
Zhao
,
Y. P.
,
Li
,
Y. C.
,
Dong
,
G. H.
, and
Gui
,
F. K.
, 2006, “
Numerical Simulation of the Hydrodynamic Behaviors of Gravity Cage in Waves
,”
Chin. Ocean Eng.
0890-5487,
21
(
2
), pp.
225
238
.
7.
Zhao
,
Y. P.
,
Li
,
Y. C.
,
Dong
,
G. H.
, and
Gui
,
F. K.
, 2007, “
Wave Theory Selection in the Simulation of Gravity Cage
,”
Proceedings of the 17th International Offshore and Polar Engineering Conference (ISOPE-2007)
, pp.
2222
2228
.
8.
Dong
,
G. H.
,
Hao
,
S. H.
,
Zong
,
Z.
, and
Zheng
,
Y. N.
, 2007, “
A Theoretical Analysis of Dynamic Elastic Response of a Circular Ring to Water Waves
,”
ASME J. Offshore Mech. Arct. Eng.
0892-7219,
129
, pp.
211
218
.
9.
Rao
,
S. S.
, and
Sundararajan
,
V.
, 1969, “
In-Plane Flexural Vibrations of Circular Rings
,”
ASME J. Appl. Mech.
0021-8936,
36
, pp.
620
625
.
10.
Blevins
,
R. D.
, 1979,
Formulas for Natural Frequency and Mode Shape
,
Van Nostrand Reinhold Company
,
New York
, pp.
203
206
.
11.
Brebbia
,
C. A.
, and
Walker
,
S.
, 1979,
Dynamic Analysis of Offshore Structures
,
Newnes-Butterworths
,
London
, pp.
109
143
.
12.
Blevins
,
R. D.
, 1984,
Applied Fluid Dynamics Handbook
,
Van Nostrand Reinhold Company
,
New York
.
13.
Gui
,
F. K.
, 2006, “
Hydrodynamic Behaviors of Deep-Water Gravity Cage
,” Ph.D. thesis, Dalian University of Technology, Dalian, in Chinese.
14.
Li
,
Y. C.
,
Gui
,
F. K.
, and
Teng
,
B.
, 2007, “
Hydrodynamic Behavior of a Straight Floating Pipe Under Wave Conditions
,”
Ocean Eng.
0029-8018,
34
, pp.
552
559
.
You do not currently have access to this content.