Strength Assessment of a Precession Driven Dynamo

Abstract

A pressure vessel, which shall be filled with eight tons of liquid sodium, has to be designed for a large-scale experimental setup to investigate flow-induced magnetic fields. In addition to the centrifugal forces and gyroscopic loads induced by the rotation about two non-parallel axes, the complex internal pressure distribution, the imbalance of the container, as well as the thermal loads resulting from the elevated temperatures, which are required for the experiments, must be taken into account. This leads to several millions of load cases. That is why a calculation procedure is developed using the finite element method, which strongly reduces the computational complexity by utilizing sector symmetry, load case decomposition and superposition. Here, the focus is to determine the most critical load cases, which will be used for the strength assessment, regarding both the static and the fatigue strength.
Besides the structural strength, the welded joints and the bolted joints are analyzed. Therefore, nonlinear effects are considered, for example the contact status of the bolted joints. The submodelling technique is used to investigate structural details.