Steam turbines are subjected to extreme thermal expansion due to high operating temperatures, which can lead to excessive vibration amplitudes and/or elevated bearing metal temperatures. Uneven thermal expansion can cause casing distortion, misalignment, and pipe strain, and in some cases may even lead to rotor–casing rubbing. These conditions may prevent the unit from reaching normal operating states, resulting in penalties within the power generation industry. Thermal (load

Subsynchronous rub simulated in rotor kit with rubbing screw Rubbing occurs when rotating machine parts come into contact with stationary components. It is one of the most frequent malfunctions in rotating machinery, yet remains difficult to diagnose because vibration responses may appear as subsynchronous, synchronous, or supersynchronous (including harmonics). Accurate diagnosis requires a clear understanding of vibration characteristics, machine configuration, and dynamic