Review of Pressurized Vessel Structural Design – An Assessment of Total Life

Abstract

The paper discusses life prediction of pressurized cylindrical container because of its dangerous failure during usage. The fatigue of material and crack propagation were obvious from the fracture surface. Crack initiation was located in the notch root of the thread. Our goal was to review the vessel structural design based on its technical documentation. Two approaches for estimating the crack initiation period were used. As input parameters, stress strain relations in the notch were obtained from FEM analysis, done in ANSYS Workbench. The first approach makes use of Neubers rule based on elastic-plastic shakedown and cyclic stressstrain curve. The second concept (which is described in ČSN EN 13445-3 or AD 2000 Mekblatt S2 respectively) uses elastic shakedown. Included stress-life curves leads to the number of cycles to crack initiation. Finally the subcritical crack growth period and final fracture were estimated = the total life was evaluated.The paper discusses life prediction of pressurized cylindrical container because of its dangerous failure during usage. The fatigue of material and crack propagation were obvious from the fracture surface. Crack initiation was located in the notch root of the thread. Our goal was to review the vessel structural design based on its technical documentation. Two approaches for estimating the crack initiation period were used. As input parameters, stress strain relations in the notch were obtained from FEM analysis, done in ANSYS Workbench. The first approach makes use of Neubers rule based on elastic-plastic shakedown and cyclic stressstrain curve. The second concept (which is described in ČSN EN 13445-3 or AD 2000 Mekblatt S2 respectively) uses elastic shakedown. Included stress-life curves leads to the number of cycles to crack initiation. Finally the subcritical crack growth period and final fracture were estimated = the total life was evaluated.