Cargo Tank Thermal Stress Analysis Of Membrane Tank LNG Carrier And Its Impact On Strength

Main characteristics of membrane tank LNG carriers is how to achieve safe carriage of LNG cargo at the very low temprature of-163℃which would be gotten through accurate heat transfer analysis, to find temperature distribution in the hull, then design of structural materials grades and size under the temperature, and the main contents are as follows:1. Temperature field prediction of large LNG vessels under different conditions is more complex, the paper is mainly about research on the solution method of static temperature field, in accordance with the "IGC rules" and requirement of the USCG technical standards, the temperature of both atmosphere and seawater, also work only carried out under the primary or secondary barriers of the cargo containment system, the temperature distribution throughout the hull structure could be calculated by such a heat transfer analysis;2. To determine the material steel grade of low temperature steel. Because of LNG carrier loading extremely low temperatures, liquid cargo, and primary and secondary barriers of cargo containment system can not completely mask the impact of low temperature, so appropriate cryogenic ductility is to be required for selection of hull structural material grades at the stage of design;3. Take an analysis and assessment on thermal stress of the hull component which has larger temperature gradient, and thus a large LNG carrier's hull structure in the transport is safe;4. To determine the design load of large LNG carrier and its cargo containment system. Establishment of large LNG carrier cargo tanks's finite element model, combination of the external wave loads and temperature loads into a variety load cases added to structural model, through the structural response analysis, then take a yield and buckling strength assessment. The aim is for strength verification on the main components of the cargo tank areas;5. The temperature forecast is the starting point of this paper work, so whether it's accurate or not is crucial. Preliminarily analyze the factors to accurately predict the temperature field and obtain the error sensitivity of temperature.