Comparison of Flange Stress Calculated by ASME Design Code and Finite Element Analysis

A flange strength calculation method for flange joints based on the researches carried out by Waters at el. is adopted in ASME B&PV Code and has been used with many good practices in several decades. However, it is also the fact that there are some cases like that the code calculation gives over conservative results or a leakage trouble occurs even if the calculation meets the code requirements. Discrepancy is pointed out between the calculation condition and the actual condition, too. This paper clarifies the difference of flange stresses calculated by ASME design code and finite element analysis. Furthermore, using the ASME Code formulas proposed by Waters with the bolt load and the gasket load obtained by finite element analysis, flange stresses are calculated and compared with the results of finite element analysis. Finally, the paper discusses the adequacy of flange stress calculation formulas and shows the point to be modified in ASME design method.