Alternative Design Approach by Finite Element Analysis for High Pressure Equipment

Abstract

Components that are subject to pressure, typical of the pressure vessel industry, can be designed using such calculation methods as “Design by Rule-DBF” or “Design by Analysis-DBA”. DBA, based on the FEM, is used increasingly often because, in addition to providing a reduction in thickness due to the lower uncertainty on the calculation, it helps to verify and study physical phenomena and complex geometry that are otherwise difficult to research while offering a more intuitive usability of the results. In this paper we wish to offer, in an educative and qualitative manner, a general overview of DBA from the creation of the model to obtaining the results, describing the types of analysis that can be carried out according to the constitutive model of the material used and the degree of accuracy that can be achieved. At the end, we cover some case studies in which DBA has been successfully used to verify design or particular conditions (such as heat treatments) for pressure vessels fabrication. The DBA calculation, described in this paper, is used with the same computational methods for high, medium or low pressure components, but it is clear that the most significant reduction in thickness is for high pressure components such as reactors, which is why the DBA calculation is particularly appreciated for this type of equipment. In the context of this paper “high pressure equipment” means when the ratio of the inner diameter to thickness of the walls is < 30.