Optimizing the Effect of Stiffening Ring on a Vessel under External Pressure by Numerical Analysis

Abstract

External pressure can cause buckling of the vessel, which results in complete destruction of the vessel. The aim of this research is to get an optimum effect of the stiffening ring attached on outer diameter of vessel under external pressure, such that vessel weight and cost reduces and the buckling stability increase. The vessel considered in this study is a horizontal saddle supported vessel having elliptical dish ends, subjected to external pressure, with and without stiffening rings. This thesis begins with the design of vessel without rings under full vacuum using PV-Elite that based on ASME codes. The output results of the PV-Elite is used as input data for Creo Parametric and ANSYS 17.0. Eigenvalue buckling analysis is performed to predict the critical buckling pressure of unstiffened vessel using the ANSYS 17.0.  Then the vessel is stiffened by adding rings to its outer dia. The effect of ring is optimized for minimum weight, cost and more buckling stability as compared to vessel without rings. The results show that using rings of suitable size, number and spacing between rings, the weight & cost of the vessel can be reduced up to 38% and the buckling stability is increased up to 6 %.