Operational Deflection Shape

Operational Deflection Shape (ODS) models are an excellent technique for observing the real-world behaviour of a system and establishing how the equipment behaves in response to force vibrations.

ODS differs from dynamic modelling which simulates behaviour.  The resulting ODS is the actual machine response and so contains components of both the forced and resonant vibration.

ODS analysis is a powerful modal testing technique used to help visualise the motion associated with vibration.  The technique works by creating a model of the object and taking recordings of vibration measurements from various points across the object’s structure, known as degrees of freedom (DOF).  Measurements are then made for the range of running conditions and excitations that the machinery typically operates.  By applying measurements to the model, it is then possible to animate the system to view its response to vibration.  Animations are made in the time domain so that problems during specific events can be viewed, for example, excessive movement during start-up.  Animations can also be created in the frequency domain allowing the visualisation of the machine’s modal response at any given frequency.

  • Uses input from real-world sensors and animations represent these real-world forced vibrations
  • Absolute dynamic behaviour of a machine and or structure
  • Time domain response of typical running and start and stop
  • Frequency or spectral ODS to view specific frequencies
  • Visualise the relative motion of system components
  • Highlight excessive flex or decoupling