Application of Finite Element in Accurate Calculations of Stresses in Expansion Joints

In order to evaluate the stiffness and perform detailed stress analysis of thick wall flange and flued expansion joint, a computer program based on finite element method was developed in C++, using 8-node axisymmetric element. Traditionally the analysis of expansion joints had been performed using the plate and beam theory which had several limitations and lead to inaccurate estimation of expansion joint stiffness and stresses. In this paper, initially the finite element mathematical model will be discussed, followed by comparison of the results of the stiffness calculations and stress analysis from the past method and that of the above-mentioned finite element model, and finally summarized by some discussions on the dependency of the accuracy of the results on the mesh density of the finite element model. The aforementioned finite element engine would be integrated to the pressure vessel and heat exchanger mechanical design software, AutoPIPE Vessel in the near future.