Vol 17, No 2 (2013) > Articles >

Fatigue Life Prediction of the Keel Structure of a Tsunami Buoy Using Spectral Fatigue Analysis Method

Angga Yustiawan 1 , Ketut Suastika 1 , Wibowo Nugroho 2


  1. Department of Naval Architecture and Shipbuilding Engineering, Faculty of Marine Technology, Institut Teknologi Sepuluh Nopember (ITS), Surabaya 60111, Indonesia
  2. UPT Balai Pengkajian dan Penelitian Hidrodinamika, BPP-Teknologi, Surabaya 60111, Indonesia



One  of  the  components  of  the  Indonesia  Tsunami  Early  Warning  System  (InaTEWS)  is  a  surface  buoy.  The  surface buoy  is  exposed  to  dynamic  and  random  loadings  while  operating  at  sea,  particularly  due  to  waves.  Because  of  the cyclic  nature  of  the  wave  load,  this  may  result  in  a fatigue  damage  of  the  keel  structure,  which  connects  the  mooring line  with  the  buoy  hull.  The  operating  location  of  the buoy  is  off  the  Java  South  Coast  at  the  coordinate (10.3998  S, 108.3417  E). To  determine  the  stress  transfer  function, model  tests  were  performed,  measuring  the  buoy  motions  and the stress at the mooring line. A spectral fatigue analysis method is applied for the purpose of estimating the fatigue life of the keel structure. Utilizing the  model-test results, the S-N curve obtained in a previous study and the  wave data at the buoy location, it is found that the fatigue life of the keel structure is approximately 11 years.

Keywords: fatigue life, keel structure, spectral fatigue analysis, tsunami buoy
Published at: Vol 17, No 2 (2013) pages: 79-86

Access Counter: 2035 views, 1058 PDF downloads, .

Full PDF Download


Badan Meteorologi, Klimatologi dan Geofisika (BMKG), InaTEWS (Indonesia Tsunami Early Warning System): Konsep dan Implementasi, Jakarta, 2010 (in Indonesian).

Sahlan, MSc Thesis, Faculty of Marine Technology, ITS Surabaya, Indonesia, 2011 (in Indonesian).

Sahlan, Soeweify, W.H. Putra, I.K. Suastika, W.H. Nugroho, Prosiding Seminar Pascasarjana XI-ITS, Surabaya, Indonesia, 2011, p.381 (in Indonesian).

P.H. Wirsching, M.C. Light, J. Struct. Div. ASCE. 106/7 (1980) 1593.

K. Ortiz, N.K. Chen, Proc. Fifth Int. Conf. on Application of Statistics and Probability in Soil and Struct. Eng., Vancouver, BC, 1987, p.309.

C.E. Larsen, L.D. Lutes, Prob. Eng. Mech. 6 (1991) 96.

J.M.J. Journee, W.W. Massie, Offshore Hydromechanics, 1st Ed., Delft Univ. Tech., The Netherlands, 2001, p.570.

P.D. Welch, IEEE Trans. Audio Electroacoustics, AU-15/2 (1970) 70.

N.D.P. Baltrop, A.J. Adams, Dynamic of Fixed Marine Structures, 3rd Ed., ButterworthHeinemann Ltd., Oxford, 1991, p.740.

Y. Wang, Int. J. Fatigue. 32 (2010) 310.

K.T. Nguyen, Y. Garbatov, C.G. Soares, Int. J. Fatigue. 48 (2013) 147.