USING FINITE ELEMENT ANALYSIS TO DETERMINE PIPING ELBOW BENDING MOMENT (B2) STRESS INDICES (To Purchase Call 1-800-854-7179 USA/Canada or 303-397-7956 Worldwide)
"The qualification of Class 1 and 2 piping systems to the requirements of ASME Section III requires the evaluation and limitation of primary stresses. For moment loadings this is achieved with the use of B2 stress indices. The first part of the bulletin reviews the background and history of the B2 indices and suggests a procedure for developing these indices. The suggested procedure is based upon the use of nonlinear finite element analysis (FEA). The second part is focused on examining existing data for straight pipe and 2"" schedule 40 elbows. The existing data consists of both test and FEA data. The objective was to demonstrate that the FEA methodology can simulate the nonlinear behavior of elbows and straight pipe. A new procedure for representing the material properties was developed. Using the new procedure the nonlinear response of the elbows and pipe were simulated more accurately than previously published results. The third part uses the FEA methodology to predict the global behaviors of thin-walled elbows subjected to in-plane bending. New tests were performed which served as the basis of this part of the study. It was determined that if the weld is included in the model@ the results are significantly improved. The fourth part addresses the out-of-plane loading behavior of piping elbows. New experimental data was developed and the corresponding FEA was performed. There is excellent agreement between the FEA methodology and the test results. The general conclusion is that the methodology described in this document can be used to accurately develop B2 stress indices for piping components"