Research And Application Of Risk-Based Inland Passenger Ship Intact Stability Assessment Method

With the development of inland river passenger ships towards tourism and largescale,how to ensure the safety performance of passenger ships has become a hot issue.For passenger ships,the intact stability of the ship is particularly important.Once the ship is capsized,it will cause huge loss of life and property.At present,in the process of ship form scheme optimization during the preliminary design stage,stability indices such as initial stability estimation value which meet the requirements of the specification are often taken as constraints,and according to the determined environmental conditions,the ship form scheme is checked whether meets the stability requirements.That is the so-called "rule-based design method".However,the environmental conditions facing ships are uncertain,such as extreme weather such as persistent strong winds and strong waves,or with the completion of inland waterway shipping construction projects,the navigation environment of ships changes accordingly.Even if the ship form scheme meets the requirements of relevant laws and regulations,there may still be the risk of capsizing accidents,such as the accident of“Eastern Star”.The rule-based design method cannot predict the capsizing risk of ship form schemes.Therefore,how to effectively predict the capsizing risk of inland passenger ships under uncertain environment is one of the key problems to be solved in the process of ship design.In the rule-based design method of inland passenger ships,the intact stability evaluation method is based on the existing regulations to calculate the stability index of passenger ships.This method regards the navigation environment of passenger ships as deterministic,and it is difficult to predict the intact stability risk of passenger ships when they encounter uncertain environmental changes in the future navigation process.For this reason,this paper brings in the idea of ship risk design,puts forward the probabilistic assessment method for the intact stability of inland passenger ships during the preliminary design stage of ships,constructs the key model of risk assessment,and takes the intact stability index as the objective function through practical application,thus realizes the effective assessment of the intact stability risk of inland passenger ships under various environmental conditions.The research results of this paper can provide decision-making basis for ship form scheme selection,and also provide new ideas and methods for similar research.Firstly,this paper analyses the present situation of the intact stability assessment of inland passenger ships during the preliminary design stage,points out the shortcomings of the current assessment methods,and puts forward the ways to improve them,that is,considering uncertain environmental conditions,bringing in the idea of risk-based ship design and adopting risk assessment methods.Secondly,this paper identifies the risk of intact stability of inland passenger ships.According to the characteristics of inland passenger ships,this paper compares various quantitative risk assessment methods,and proposes a risk-based probability assessment method of intact stability of inland passenger ships.Then,on the basis of linear roll theory,two key models for intact stability probabilistic assessment of inland passenger ships are established,i.e.roll frequency response model and capsizing probability calculation model,and the validity of the theoretical model is verified.Finally,taking a luxury cruise ship on the Yangtze River as an example,this paper applies the intact stability risk probability assessment method of inland passenger ship proposed in this paper to the optimization of ship form scheme in the preliminary design stage,and obtains the ship form scheme with better comprehensive performance under different environmental conditions and the corresponding capsizing probability.At the same time,the influence of ship form parameters on the intact stability of inland passenger ship is analyzed,and useful conclusions are obtained and verified.The feasibility and validity of the method are verified.