MODELLING OF CRACK IN PRESSURE VESSELS BY IGA USING THIN SHELL THEORY

Abstract

This thesis aims to model the crack on the pressure vessel surface so as its rupture can be avoided. It is well known that pressure vessel finds immense applications in almost all industries. They normally work on high pressure and extreme temperatures. Also in some typical applications they even carry highly inflammable or hazardous substances. Due to such applications it is important that they should not end up with rupture as it can cause serious destructions. Due to the presence of crack, the state of stress near the crack becomes very high, this is due to the phenomenon of stress singularity at the crack tip which greatly reduces the strength of the material and can lead to early failure. In this project, the geometry of a pressure vessel is created using splines then these splines are used as the basis for the isogeometric analysis (IGA). Initially, the stress analysis of thin pressure vessel is carried out in the absence of crack by implementing IGA based Kirchhoff- Love shell theory, and results are compared to analytical or standard available solutions, Next, a through the thickness crack (because of thin shell) is assumed in the vessel either axially or circumferentially, and a numerical analysis is performed by extended isogeometric analysis (XIGA). This thesis aims to explain the implementation fundamentals of XIGA based Kirchhoff-Love thin shell theory to the domain of shell problems. The issues faced in modeling the crack are discussed in the context