Slamming loads from plunging breaking waves feature a high impulsive force and a very short duration. It is difficult to measure these loads directly in experiments due to the dynamics of the structures. In this study, inverse approaches are investigated to estimate the local slamming loads on a jacket structure using hammer test and wave test data from a model scale experiment. First, a state-of-the-art approach is considered. It uses two deconvolution techniques to first determine the impulse response functions and then to reconstruct the wave impact forces. Second, an easier applicable approach is proposed. It uses linear regression with the ordinary least square technique for the force estimation. The results calculated with these two approaches are highly identical. The linear regression approach can be extended to account for the loads transferred among different locations. This leads to lower and theoretically more accurate estimation of the loads compared to the previous two approaches. For the investigated case, the total impulse due to the wave is 22% lower. The estimated forces by the extended approach have a resolution at the millisecond level, which provides detailed information on the shape of the forces. The approach is an important tool for statistical investigations into the local slamming forces, and further on for the development of a reliable engineering model of the forces.

References

References
1.
Chella
,
M. A.
,
Tørum
,
A.
, and
Myrhaug
,
D.
,
2012
, “
An Overview of Wave Impact Forces on Offshore Wind Turbine Substructures
,”
Energy Procedia
,
20
, pp.
217
226
.
2.
Tu
,
Y.
,
Cheng
,
Z.
, and
Muskulus
,
M.
,
2017
, “
A Review of Slamming Load Application to Offshore Wind Turbines From an Integrated Perspective
,”
Energy Procedia
, accepted.https://www.sintef.no/globalassets/project/eera-deepwind2017/posters/e_ying-tu.pdf
3.
Hallowell
,
S.
,
Myers
,
A. T.
, and
Arwade
,
S. R.
,
2016
, “
Variability of Breaking Wave Characteristics and Impact Loads on Offshore Wind Turbines Supported by Monopiles
,”
Wind Energy
,
19
(
2
), pp.
301
312
.
4.
IEC
,
2009
, “
Wind Turbines—Part 3: Design Requirements for Offshore Wind Turbines
,” 1.0 ed., International Electrotechnical Commission, Geneva, Switzerland, Standard No.
IEC 61400-3:2009
.https://webstore.iec.ch/publication/5446
5.
DNV
,
2014
, “
Offshore Standard: Design of Offshore Wind Turbine Structures
,” Det Norske Veritas, Akershus, Norway, Standard No.
DNV-OS-J101
.https://rules.dnvgl.com/docs/pdf/DNV/codes/docs/2014-05/Os-J101.pdf
6.
GL Renewables Certification
,
2012
, “
Guideline for the Certification of Offshore Wind Turbines
,” GL Renewables Certification, Hamburg, Germany.
7.
Faltinsen
,
O.
,
1993
,
Sea Loads on Ships and Offshore Structures
,
Cambridge University Press
,
Cambridge, UK
, Chap. 9.
8.
Ridley
,
J. A.
,
1982
, “
A Study of Some Theoretical Aspects of Slamming
,” National Maritime Institute, London, Technical Report No.
NMI-R-158
.https://trid.trb.org/view.aspx?id=404368
9.
Perlin
,
M.
,
Choi
,
W.
, and
Tian
,
Z.
,
2013
, “
Breaking Waves in Deep and Intermediate Waters
,”
Annu. Rev. Fluid Mech.
,
45
(
1
), pp.
115
145
.
10.
Wienke
,
J.
, and
Oumeraci
,
H.
,
2005
, “
Breaking Wave Impact Force on a Vertical and Inclined Slender Pile—Theoretical and Large-Scale Model Investigation
,”
Coastal Eng.
,
52
(
5
), pp.
435
462
.
11.
Irschik
,
K.
,
Sparboom
,
U.
, and
Oumeraci
,
H.
,
2005
, “
Breaking Wave Loads on a Slender Pile in Shallow Water
,”
Coastal Engineering 2004
, Vol.
1
,
World Scientific
,
Hackensack, NJ
, pp.
568
580
.
12.
Bredmose
,
H.
,
Slabiak
,
P.
,
Sahlberg-Nielsen
,
L.
, and
Schlütter
,
F.
,
2013
, “
Dynamic Excitation of Monopiles by Steep and Breaking Waves: Experimental and Numerical Study
,”
ASME
Paper No. OMAE2013-10948.
13.
Choi
,
S.-J.
,
Lee
,
K.-H.
, and
Gudmestad
,
O. T.
,
2015
, “
The Effect of Dynamic Amplification Due to a Structure's Vibration on Breaking Wave Impact
,”
Ocean Eng.
,
96
, pp.
8
20
.
14.
Rausa
,
I. E.
,
Muskulus
,
M.
,
Arntsen
,
Ø. A.
, and
Wåsjø
,
K.
,
2015
, “
Characterization of Wave Slamming Forces for a Truss Structure Within the Framework of the WaveSlam Project
,”
Energy Procedia
,
80
, pp.
276
283
.
15.
Tu
,
Y.
,
Muskulus
,
M.
, and
Arntsen
,
Ø. A.
,
2015
, “
Experimental Analysis of Slamming Load Characteristics for Truss Structures in Offshore Wind Applications
,”
J. Ocean Wind Energy
,
2
(
3
), pp.
138
145
.
16.
Tørum
,
A.
,
2011
, “
Wave Slamming Forces on Truss Structures in Shallow Water, Version 2011-10-03
,” Norwegian University of Science and Technology, Trondheim, Norway.
17.
Arntsen
,
Ø.
,
Obhrai
,
C.
, and
Gudmestad
,
O.
,
2013
, “
Data Storage Report: Wave Slamming Forces on Truss Structures in Shallow Water
,” WaveSlam (HylV-FZK-05), Norwegian University of Science and Technology, Trondheim, Norway.
18.
Sarkar
,
T. K.
,
Tseng
,
F. I.
,
Rao
,
S. M.
,
Dianat
,
S. A.
, and
Hollmann
,
B. Z.
,
1985
, “
Deconvolution of Impulse Response From Time-Limited Input and Output: Theory and Experiment
,”
IEEE Trans. Instrum. Meas.
,
34
(
4
), pp.
541
546
.
19.
Jacquelin
,
E.
,
Bennani
,
A.
, and
Hamelin
,
P.
,
2003
, “
Force Reconstruction: Analysis and Regularization of a Deconvolution Problem
,”
J. Sound Vib.
,
265
(
1
), pp.
81
107
.
20.
Sanchez
,
J.
, and
Benaroya
,
H.
,
2014
, “
Review of Force Reconstruction Techniques
,”
J. Sound Vib.
,
333
(
14
), pp.
2999
3018
.
21.
Ekstrom
,
M. P.
, and
Rhoads
,
R. L.
,
1974
, “
On the Application of Eigenvector Expansions to Numerical Deconvolution
,”
J. Comput. Phys.
,
14
(
4
), pp.
319
340
.
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