Strength And Stiffness Analysis And Development Of Design Software Of Vessel Flange Based On Finite Element Method

Flanges are important components of pressure vessels and pipes and play critical roles for the safety of system. The most design standards of vessel flanges are based on the Taylor-Waters method with elastic mechanics in many countries. For the purposes of improving accuracy and efficiency for designing non-standard flanges, in this thesis, the stresses and rotation angles of non-standard integrity flanges for pressure vessels were analyzed and calculated by finite element analysis (FEA). Furthermore, structural factors influencing the flange strength and stiffness are investigated. Based on the results of this study, the engineering design software CFFEA for the non-standard flanges was developed with ANSYS APDL and VB program based on the finite element analysis.Firstly, the fundamentals, calculation and design procedures of Taylor-Waters method were reviewed. The structure and dimensions of an integral flanges used in practice engineering were calculated and designed according to the formulas and procedures in ASME ?-2-4.16. The 3D finite element model for the non-standard flanges was established for analyzing and calculating the stresses and rotation angles. The results were compared with those obtained by SW6 and ASME ?-2-4.16. The assessment criteria of stresses and rotation angles of flanges were presented based on the theory of Taylor-Waters and FEA.Secondly, the influences of geometry parameters, such as conical width, conical length, flange thickness, and bolts spaces, as well as gasket width on the strength and stiffness of flanges were analyzed with FEA.Thirdly, the engineering design software CFFEA for the design of non-standard flanges was developed with the ANSYS APDL and VB program in Visual Studio 10.0 based on the finite element analysis. With the operating interfaces, this software presented a lot of functions such as calculations based on FEA and ASME ?-2-4.16 respectively, optimization design of flange structures, access to design results and generating design report etc. As an example, an integral flange used in practice was designed and optimized with this software, and the flange conform to the strength and stiffness requirements of ASME ?-2-4.16.