Study of a coupling mechanism between two bodies at high temperature values

In the frame of thermal structures design activities, particular interest covers the choice of the coupling mechanism (bolt material, preload, etc) between bodies characterized by high temperature values. In fact, those high values cause significant thermal expansion of the elements connecting the hot bodies. In particular, when two bodies made of different materials have to be joined, a difference in the thermal expansion will be encountered leading to a loosening of the coupling mechanism. The resulted bolt preload will decrease significantly. The present work illustrates a particular coupling mechanism that is able to maintain a sufficient preload even at very high temperature values. A local model has been considered for the structural analyses. The boundary conditions applied have been retrieved from the global structural analyses results. Structural non-linear analyses by means of Finite Element code ANSYS have been performed.