As the most important parts of rotating machinery, rotors are also the most prone to mechanical vibrations, which may lead to machine failure. Correction is only possible when proper and accurate diagnosis is obtained through understanding of rotor operation and all of the potential malfunctions that may occur. Mathematical modeling, in particular modal modeling, is key to understanding observed phenomena through measured data and for predicting and preventing failure. Rotordynamics advances simple yet adequate models of rotordynamic problems and phenomena related to rotor operation in its...