Investigation on theoretical solution of geometric deformation of pressure vessel and pipe subjected to thermo-mechanical loadings

The existing design codes of pressure vessel like the ASME, EN13445 and GB150 only list some calculation formulas of the wall thickness of the cylindrical, spherical or other shells, but not provide the calculation formula of the geometric deformation of these pressure components. Based on the thermo-elastic theory and non-zero axial strain, the exact theoretical formulas of the radial and axial displacements were derived by the four order differential equation of deflection at the edge zone for a cylindrical vessel and a pipe subjected to the thermo-mechanical loadings, respectively. The proposed theoretical solutions were in good agreement with the finite element (FE) numerical solutions. In addition, the influence of edge effect on the geometric deformation of the pressure components was discussed in detail. The calculation formulas developed in this work can be used to precisely calculate the geometrical deformation of the pressure vessel and pipe, which will make the installation process of the pressure system more reliable.