6. Varying force-induced displacements

The displacements induced in HPs by mechanical loads can be considered elastic and proportional to the load. For the disk and the blade, the main load is a centrifugal force and the displacements will be proportional to the rotation speed squared n2 . As the casing is mainly loaded by a pressure force, the displacement will linearly depend on the HPC pressure PHPC. The action of these forces has no delay and the displacement will change along with the load change.

However, since the elasticity coefficient depends on the HP temperature, the HP displacement should be simulated regarding this dependency. The temperature distribution within HP is nonuniform and dynamically changes during transient engine operation. For this reason, it will be difficult to directly simulate the

elasticity change. To solve this problem, paper [22] proposes the concept of an equivalent temperature.
