Lateral Vibration Analysis

INERTANCE has performed the lateral vibration analysis (rotor dynamics analysis) with necessary design tools for turbo-machinery that includes centrifugal and axial compressors, centrifugal pumps, steam & gas turbines, motors, and gear applications. The rotor components including blades, impellers, etc have been modeled based on manufactured drawings, which can generate a mass-elastic lateral model of rotor assembly.

INERTANCE has a capability to perform below kinds of rotor dynamics analysis.

  • Lateral vibration analysis
  • Rotor dynamics analysis
  • Damped eigenvalue (Critical speed) analysis
  • Undamped critical speed map
  • Train lateral vibration analysis
  • Mode shape
  • Campbell diagram analysis
  • Bearing stiffness and damping coefficients
  • Separation margins as per API requirements
  • Forced response analysis (Unbalance response analysis)
  • Bearing clearance assessment
  • Stability analysis
  • Log decrement
  • Oil whirl and whip against rotor instabilities
  • Transient analysis
  • Forward and backward mode
  • As per API 610, 611, 612, 617, 672, 684, etc. (Any other API Standard)

In addition, the linearized coefficients are calculated for various bearing types with application of any seal type step by step. INERTANCE can provide various kinds of rotor dynamics analysis as requested in API standards as below.

Here, INERTANCE can show the various type of lateral vibration analysis as follows;



1. Undamped Critical Speed Map

Undamped critical speed analysis is very useful to understand the critical speed and mode shape characteristics briefly. Based on undamped critical speed map, the amplification factor as well as rotor behavior can be predicted.


2. Mode Shape

Mode shape provides the approximate displacement of rotor relatively around critical speed, and it is determined that the unbalance location with phase is applied for response analysis.


3. Unbalance Response Analysis

Damped unbalance response analysis is performed to check the adequate separation margin between critical speeds and operating speeds, as well as to check  internal clearance limitation against rubbing, etc.


4. Level I, II Analysis

The rotor stability analysis is used to estimate the high amplification factor of first critical speed for sensitive machine, and it is composed with simplified Level I and detailed Level II analysis.

[Level I Analysis]


[Level II Analysis]