Abstract: Exemplary embodiments simulate the eigenmodes of a flexible rotor in a model of a rotor and thus reduce the number of variables and computation expense required during simulation of the transverse motion response of the rotor. The exemplary embodiments may use data structures, such as lookup tables, to store precomputed information that may be used for the determining eigenmode properties as the values of one or more parameters affecting the eigenmode properties (e.g., speed, shaft temperature, bearing viscosity, normal force acting along the rotor shaft axis, turbine power level, turbine fluid flow rate, etc.) change during a simulation. The use of the data structures helps to reduce the computational expense during the simulation.