Probability of Failure of Damaged Ship Structures – Phase 3


  1. Akpan, U.
  2. Yuen, B.
  3. Koko, T.S.
  4. Lin, F.
  5. Wallace, J.
Corporate Authors
Defence Research and Development Canada, Atlantic Research Centre, Halifax NS (CAN);MARTEC Ltd, Halifax NS (CAN)
The methodology developed in Phase II for assessing the reliability of damaged ships is applied to a damaged ex-HMCS Nipigon. The midship section of the vessel is used in the analysis. The statistics of the maximum damaged length and the maximum penetration depths are determined with SIMCOL and COMPASS. Operational profiles for the damaged vessel are defined and WAVELOAD is used to compute the response amplitude operators, RAOs, of the waves on the vessel. The extreme values of the wave loads are also calculated and calibrated, and TRIDENT is used to estimate the still water bending moments. The ultimate bending moment capacities of the intact and the damaged vessel are calculated using ULTMAT. The damage size feature of ULTMAT is used to estimate the ultimate bending moment capacities interaction curves for damage sphere sizes of 2 m 3 m, 4 m, 5 m, and 6 m. These values are then used to determine the mean values, standard deviations and interaction coefficients for the damaged vessel. The linear and interaction equations limit state functions are defined and employed in COMPASS to estimate the reliabilities and the important factors of the random variables. Both the first order reliability method, FORM, and the Monte Carlo Simulation method, MCS, are used. The result of the analyses indicate that for the selected operational profile defined by the computed wave loads, and the vessel ultimate bending moment capacities and a specified limit state function, the probability of f
Ship structure;damage;reliability;sea loads
Report Number
DRDC-RDDC-2014-C45 — Contract Report
Date of publication
01 Apr 2014
Number of Pages
Electronic Document(PDF)

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