phone + 1.916.660.0444
fax + 1.916.660.0222

2-D FEA Rotordynamics Analysis


RAPPID™ 2D finite element rotordynamics analysis software utilizes conical beam elements to enable modeling of an unlimited number of rotating and stationary structures. A variety of analyses can be completed, including:

  • Free-free rotor and housing modes
  • Undamped critical speeds and housing natural frequencies
  • Damped eigenvalues, stability, and mode shapes
  • Synchronous and asynchronous forced response
  • Asynchronous response can be constant rotor speed or constant harmonic order
  • Nonlinear transient forced response

Advanced Features

RAPPID™ 2D finite element rotordynamics analysis software has many flexible features, including:

  • Rotors and housings may have any relative orientation in 3D space
  • Each rotor and housing entity modeled with 2D conical beam elements
  • Each rotating assembly is assigned a speed and direction
  • Analysis of co-rotating, counter rotating, and co-axial rotors
  • All DOFs are included for analysis of coupled axial, torsional, and lateral modes
  • Up to 108 rotordynamic coefficients for each interconnection
  • Unlimited number of forcing functions
  • Forcing functions may be defined with magnitudes that are constant or a function of frequency squared


RAPPID™ 2D finite element rotordynamics analysis software has unique postprocessing capabilities, including:

  • Automatic generation of geometry plot with only user selected nodes and load paths
  • Natural Frequency Map, Stability Map, Root Locus Plot, and 3D Mode Shapes
  • Rotor modes are automatically sorted and labeled along with user defined operating range
  • User defined harmoic lines are displayed and interferences automatically labeled
  • Mode Shape plots with natural frequency, synchronous critical speed(s), stability parameter, and whirl direction
  • Rotor Displacements, Dynamic Loads, and Response Shapes.
  • Response plots are created in fixed X-Y and rotating Major/Minor coordinate systems
  • Amplification factors (AF) automatically calculated
  • AF displayed on X-Y response plots with corresponding peak frequency response
  • User defined rub limits displayed on Major/Minor response plots
  • Separation margins relative to a user defined operating range are automatically displayed
  • Plot responses from different rotor stations and/or different analysis runs on same plot
  • Animation program included to illustrate rotor modes amd response shapes