Probability-Based Ship Structural Safety Analysis

Abstract

This paper provides a demonstration on the use of probability-based ship structural safety analysis and enumerates the benefits in comparison with traditional methods. Reliability techniques are developed to determine safety levels of existing vessels, taking into consideration uncertainties in loads, strength and calculation procedures. Ultimate, serviceability and fatigue limit states are developed and applied to an existing tanker. The corresponding load models are examined and, in some instances, further developed. Safety indices associated with yielding, buckling, and fatigue are calculated. Conclusions are drawn regarding the benefits and drawbacks of using probability-based ship safety analysis. This paper provides a demonstration on the use of probability-based ship structural safety analysis and enumerates the benefits in comparison with traditional methods. Reliability techniques are developed to determine safety levels of existing vessels, taking into consideration uncertainties in loads, strength and calculation procedures. Ultimate, serviceability and fatigue limit states are developed and applied to an existing tanker. The corresponding load models are examined and, in some instances, further developed. Safety indices associated with yielding, buckling, and fatigue are calculated. Conclusions are drawn regarding the benefits and drawbacks of using probability-based ship safety analysis.

Reliability assessment of ship hull girders considering pitting corrosion and crack

“…where, ( ) M t sw is the still water bending moment, and ( ) M t w is the wave bending moment. A simple linear model for the limit state function of ultimate strength of ship hull girder is given by Mansour [27] as follows:…”

Quantifying uncertainties for Risk-Based Inspection planning using in-service Hull Structure Monitoring of FPSO hulls

“…An early example of the application of reliability methods is provided by [13]. Overviews of the basic methodologies which still form the core of most modern day analysis are provided in [14,15]. These references cover the basic concepts which are used throughout the present paper including uncertainty models, First/Second Order Reliability Methods and Monte Carlo simulations.…”

“…There are additional challenges when considering the reliability of a whole system rather than a single component. [14] examines the reliability of systems under more or less correlation between the components of the system. A general framework for system reliability incorporating fatigue degradation in steel structures is provided by [32] using Bayesian decision theory to develop an inspection plan based on a system consisting of 20 structural components.…”

The Reliability Assessment of a Ship Structure under Corrosion and Fatigue, using Structural Health Monitoring

“…where 𝑀 𝑢 is the ultimate capacity of the bending moment of the main beam, 𝑀 𝑠𝑤 shows the bending moment resulted from the still water surface, 𝑀 𝑤 is the bending moment caused by the wave, 𝑘 𝐷 is the correction coefficient between the bending moment of the wave and the dynamic bending moment, 𝑀 𝐷𝑦𝑛 indicates dynamic bending moment. 𝑘 𝑤 is the correlation coefficient that depends on the bending due to stress in the sagging state or stress in the hogging state [25,26].…”