Thermodynamic Response And Ultimate Strength Of Deck Grillage Exposed To Fire

Ship cabin fire is easy to cause serious casualties and property losses.In the case of high temperature,the cabin structures’ temperature and thermal stress will rise rapidly.Meanwhile,the material mechanical properties of the structures will decline rapidly with the rise of temperature,which will jointly lead to the decline of the cabin structures’ bearing capacity.Therefore,it is necessary to analyze the thermodynamic response and ultimate strength of typical components exposed to fire.In this thesis,Fire Dynamics Simulation(FDS)software based on large eddy simulation algorithm is used to simulate cabin fire.This thesis considers the thermal convection and thermal radiation between structures and ambient air,and the initial imperfection of the structures and hightemperature thermodynamic characteristics of the material are also considered.Then the dynamic thermodynamic response of the deck grillage during the fire process is calculated by sequential thermodynamic coupling algorithm,and the residual high-temperature ultimate strength of the deck grillage under axial compression load is studied based on the explicit dynamic algorithm.In this thesis,the thermodynamic response and the residual ultimate strength of the deck grillage in the enclosed cabin fire are firstly carried out and the failure mode of the deck grillage is also analyzed,then the influence of the oil tank in different positions on the strength of deck grillage is compared.This thesis also considers fire scenarios with different atmospheric conditions and different oil pool areas,and analyzes the development of cabin fire in different fire scenarios,and the influence of different fire conditions on the thermodynamic response and residual strength of the grillage is compared;meanwhile,oxygen control,fuel control and transition fire types are summarized.It is found that the large oil pool fire poses a greater threat to the structure in the early stage,and the transitional fire poses a greater threat in the middle and late stage;finally,the thermodynamic response and strength of deck grillage with fireproof coating are studied,and the influence of different coating positions on the strength of grillage is analyzed.It is found that fireproof coating can effectively prevent transfer of heat,and the protection of deck plate and longitudinal is particularly important for the improvement of the grillage’s ultimate strength.As an effective means of analyzing the thermodynamic and ultimate strength of structures of ships and marine structures exposed to fire,the research work in this thesis can provide references for the fire-resistant design and safety evaluation.