Modelování šroubované nádrže: Modální analýza se zahrnutím vlivu uskladněné kapaliny

Abstract

This master’s thesis focuses on modal analysis using different approaches to incorporate the influence of stored liquid in a tank, with the aim of applying the developed model in practice. The study examines bolted tanks consisting of a set of curved plates joined by bolted connections. It investigates the effect of liquid distribution on the floor and shell surfaces, as well as the impact of stiffeners and the number of rings on natural frequencies. The work focuses on the development of numerical models and their subsequent verification through experimental measurements performed on a bolted tank prototype. Initially, various approaches to simulating stored liquid in tanks and numerical methods for calculating eigenvalues and eigenvectors are described. This is followed by the design and implementation of numerical models and their solution. The results are verified by experimental measurement. The findings indicate that simulations using shell elements, where the liquid is represented by mass distribution along the container wall, are not as accurate as results obtained from a numerical model describing fluid structure interaction. However, a significant reduction in computational time is demonstrated when using a diagonal mass matrix without a substantial loss of accuracy, proving its practical applicability for large capacity tanks.