Design And Temperature Field Analysis On The Support Structure Of IMO A-Type LNG Carrier

The weight of independent tank and loading cargo of IMO A-type LNG carrier is passed to the main hull structure by supports,at the same time,the movement of main hull and internal goods of tank in waves caused by dynamic load is need to be considered.The temperature of LNG is-163℃,and the heat exchange exsit in air,water and ship.A number of supports is used to support tanks and cut off the low temperatur.Therefore,it is of certain significance to actively study the design of supports structure and temperature field analysis of IMO A-type LNG carrier.In this paper,the IMO A-type LNG carrier is taken as the research object,and a series of studies are carried out on its strength and temperature field.Firstly,the position of the support is arranged by using the method of direct calculation;Secondly,the structure of the support structure is improved by using the method of grid subdivision;Finally,the temperature field of its support is analyzed,so as to select the steel grade of hull material near the support.The main contents of this paper are as follows:(1)The structure of the A-type LNG carrier,the inner structure of the tank,the primary and secondary shielding layer are introduced in detail,and it also enumerates types of existing supporting system and the failure mode of the support.Finally,according to support of C-type LNG carrier,the type of support and the initial installation position of A-type tank are designed according to the characteristics of the A-type tank and the movement state of hull under different working conditions.(2)The design support structure of A-type LNG carrier is given.,then we use the direct calculation method and ANSYS software to calculate “1/2 + 1 + 1/2” hull,we use the spring element to simulate the wooden block.Under the load cases of the combined action of dynamic and static loads,the calculated stress values of the wooden block are obtained,the reasonable scheme of the mounting position of the support is defined.Based on this,the factors that influence the force in all directions of the support are analyzed.(3)Based on the IGC code,the further subdivision is required for grid of support structure in actual work.In the way of adding the number of spring,we can calculate the vertical load of supports.We adopt the way of adding longitudinal and transverse node pressure on supports,we need to find out the most dangerous parts of supports in the finite element calculation,and improve the support structure.(4)The material choice of hull structure near support structure is studied mainly.A-type LNG tank container is in low temperature condition,low temperature is passed to the hull through supports and insulating layer,temperature gradient effected by supports will affect material properties,finally determine the hull material steel grade combined with its minimum allowable design temperature,which also verifies the thermal insulation properties of wooden blocks.