8 Analysis of Components in VIII-2

Section VIII-2 requires stress analysis of vessel components when explicit design formulas are not given. This includes flued-in heads, head-to-shell junctions, expansion joints, thermal stresses, and stresses in components due to loads other than pressure. In performing the stress evaluation, the designer must determine the maximum stress at a given point or location. When computer programs such as ANSYS and NASTRAN are used to determine the stress, the output usually consists of the total combined stress at a given point. This stress must then be separated into its components of membrane, bending, and peak stresses. This is necessary in order to compare each of these components to a corresponding allowable stress given in VIII-2 or to properly establish an allowable fatigue life. In this chapter only stress categories, stress concentrations, combinations of stresses, and fatigue evaluation are discussed in accordance with the definitions and requirements of VIII-2.