Strength Analysis And Structural Optimization Of Austenitic Stainless Steel Cold Stretching Transportable Cryogenic Vessel

The wall thickness of austenitic stainless steel cryogenic vessels can be reduced by adopting the cold stretching technology to achieve structural lightweight.At present the technology has been used for fixed cryogenic vessel,but it has not been used for transportable cryogenic vessel on account of lacking of related basic research.In this paper,the austenitic stainless steel strain-strengthening transportable cryogenic vessel was regarded as the research object.Based on failure mode of the ductile fracture and fatigue fracture,structural strength of the vessel was checked by nonlinear finite element analysis method.Parametric analysis was carried out on reinforcement structure of the support region in inner vessel.The main research work and conclusions are listed as below.(1)According to the characteristics of transportable pressure vessel that plastic strain of inner vessel should not be too large,it was obtained that strain constraints was ?=min{?410,5%} and strengthening stress was Rx=min{410MPa,?5%} Then strengthening pressure Pkwas determined by the modified formula according to the selected strength Rk.(2)The study of numerical simulation was carried out for transportable pressure vessel.Through force analysis on the vessel under different conditions,it was found that the largest stress all appeared on reinforcing ring in fixed end support region,which surpassed the allowable stress value at room temperature of austenitic stainless steel that was a safety risk.(3)Based on failure modes of ductile fracture and fatigue fracture,the structural strength of vessel was checked.The results of finite element analysis indicated that the failure didn't occur in the vessel in actual transport process.(4)The effects upon the stress of vessel of type and arrangement of reinforcing ring and parameters of local thickening structure were studied.Compared effects upon the stress distribution of vessel of reinforcing ring structure with local thickening structure,the results showed that the latter structure was easier to improve stress of the vessel.