The effects of stochastic characteristics of materials on the reliability of a composite ship hull

Abstract

The effects of stochastic characteristics of materials on the reliability of ship hulls made of composite materials under longitudinal moment were extensively studied using reliability and sensitivity calculations of a composite ship hull which was sagging. The reliability indices and failure probabilities of the ship in three kinds of failure modes (buckling, material failure, and ultimate collapse) were calculated by the surface response method and JC method. The importance factors of random variables in stochastic models, such as the model errors in predicting the ultimate longitudinal strength of ship and the longitudinal bending moment that the ship withstands, as well as the stochastic characteristics of materials in the models used, were calculated. Then, the effects of these random variables, including the stochastic characteristics of materials on the reliability index and the failure probability of ships which were sagging, were discussed with their importance factors. The results show that the effects of stochastic characteristics of materials on the reliability of ship hulls made of composite materials should be considered during the reliability assessment of composite ships. Finally, some conclusions and recommendations were given for high-speed ship design and safety assessment.

Keywords

composite material / reliability analysis / response-surface method / sensitivity analysis

References

[1] Chen N. Longitudinal strength analysis of ship hulls of composite materials under sagging moments. Composite Structures, 2007, 77(1): 36-44

[2] Guedes S. C. Reliability engineering and system safety. Reliability of Components in Composite Materials, 1997, 55: 171-177

[3] Gurvich M.R., Pipes R.B. Reliability of composites in a random stress state. Composites Science and Technology, 1998, 58(6): 871-881

[4] Ibnabdeljalil M., Curtin W.A. Strength and reliability of fiber-reinforced composites: localized load-sharing and associated size effects. International Journal of Solids and Structures, 1997, 34(21): 2649-2668

[5] Kam T.Y., Lin S.C. Reliability analysis of laminated composite plates. Proc. NSC, Part A, 1992, 16: 163-171

[6] Kam T.Y., Lin S.C., Hsiao K.M. Reliability analysis of nonlinear laminated composite plate structures. Composite Structures, 1993, 25: 503-510

[7] Lin S.C., Kam T.Y., Chu K.H. Evaluation of buckling and first-Ply failure probabilities of composite laminates. International Journal of Solids and Structures, 1998, 35(13): 1395-1410

[8] Mansour A.E., Wirsching P.H., Lucket M.D., Plumpton A.M., Lin Y.H. Structural safety of ships. Transactions of the Society of Naval Architects and Marine Engineers, 1997, 105: 61-98

[9] Mansour A.E., Wirsching P.H., Lucket M.D., Plumpton A.M., Lin Y.H. Assessment of reliability of existing ship structures, 1997, Washington DC: SSC-398, U.S. Coast Guard

[10] Sun H., Chen N., Zhang S. Ultimate Strength and reliability analysis of high-speed ship in composite materials. Engineering Mechanics, 2002, 19(2): 124-128

[11] Sutherland L.S., Guedes Soares C. Review of probabilistic models of the strength of composite materials. Reliability Engineering and System Safety, 1997, 56: 183-196

[12] Yushanov S.P., Bogdanovich S.E. Analytical probabilistic modelling of initial failure and reliability of laminated composite structures. International Journal of Solids and Structures, 1998, 35(7–8): 665-685

[13] Zhao G. Theory and application of engineering structure reliability, 1996, Dalian: Dalian University of Technology Press, 145-158

[14] Zhu J., Guo J., Cao M. Reliability analysis of composite ship structures. Shipbuilding of China, 1996, 4: 32-40