Finite Element And Fatigue Analysis Of Shrunk-on Ultra High Pressure Vessel

The ultra high pressure food processing (UHPP) technology starts in the late19thcentury. Not only it can keep the food color, smell, taste and biological activity butalso play a role in food sterilization. The UHPP technology is being widely used. TheUHPP technology has entered the stage of industrial application, with the constantpursuit of health and safety food, it will become a new technology with potential andmarket prospect. The core part of the UHPP equipment is the ultra high pressurevessel (UHPV). The research on how to improve the food processing capability of theUHPV has great practical significance.The stress condition and fatigue state of the UHPV various parts will be studiedin this paper. The key dimension of the UHPV cylinder was optimized on the basis ofFEA, which made the optimized structure more reasonable. The digital imagecorrelation method (DIC) was used to measure the surface deformation of the UHPVin the working state. The DIC method will provide the theoretical and practicalreference for the future research on the food processing UHPV. The details are asfollows:1、The general-purpose finite element analysis (FEA) software of ANSYS was usedin studying the cylinder of shrunk-on UHPV. The stress distribution of pre-stress andworking state could be acquired through the FEA. The actual loading process of thecylinder could be simulated by the ANSYS, the stress transferring process from innercylinder to outer cylinder could be seen when the UHPV was at work. It wascalculated that the values of the three-dimensional stress and considerable stress intwo states of the UHPV cylinder, compared with the value with FEA results and theyverified the accuracy of FEA. After the analysis was completed, the optimizationmodule of ANSYS was used in optimizing and improving the design of UHPVcylinder. So that the optimized cylinder structure is more reasonable and matches withthe practical needs2、CATIA was used in creating the three-dimensional model of the seal structure ofUHPV upper petals cover, and the model was imported into ANSYS for FEA. The stress distribution and the maximum stress locations of entire seal structure. TheATUOCAD was used to create the two-dimensional thread model of flange cover andouter cylinder connecting portion. The threaded was imported model into ANSYS forfinite element analysis, and the loads distribution on the entire thread was obtained.Both ends of the thread pairs need to bear tremendous loads from the analysis resultsand the loads that in the middle of the thread pairs are smaller than other locations.For single screw thread, the bottom of the screw is could cause stress concentration.The stress distribution of flange thread and cylinder thread show some regular pattern.3、Fe-safe (professional fatigue analysis software) was used for fatigue analysis ofthe upper portion and the threaded connect parts of UHPV. The calculation resultshows that the fatigue life of the entire UHPV is lager than106, the service life of theUPHV can more than30years under the maximum working pressure. The minimumsafety factor of the UHPV is lager than1.1under the maximum pressure. Thecalculated fatigue information can provide reference and basis for repair andmaintenance the UHPV. We can not only save the time for maintenance but alsoimprove the work efficiency whose attention was focused on the parts that low life orimportant safty factors. So there is a good economic and engineering significance foranalyzing the UHPV by the fatigue analysis software.4、The digital image correlation method (DIC) was used to measure deformationfield of tooth-locked closure flange of the UHPV in reality. The displacement contourcould be obtained by the experimental analysis. The experiment results will becompared with FEA result to verify the accuracy of FEA method. The experimentresults can achieve to the expected effect, and it also provides a reality reference andbasis for measuring the stress and displacement of the UHPV.