# ODS Operating Deflection Shape

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• Last Post 03 May 2018
Bruno Piola posted this 09 February 2018

How is step one step to perform an ODS (Operating Deflection Shape) with Ansys?

peteroznewman posted this 09 February 2018

ODS usually refers to taking accelerometer data at many points on a structure and using ODS software to map the accelerometer data to a very coarse representation of the geometry to visualize the vibration mode shapes and determine the frequencies of the structure.

ANSYS can simulate the vibration shapes of a structure that is subject to a harmonic excitation, it is called Harmonic Analysis. Here is my example of a bridge. A more typical example would be a machine with an out-of-balance rotor causing a harmonic load on the structure.

Please provide an image of a typical example you are interested in simulating. Do you have geometry for the structure?

Bruno Piola posted this 12 February 2018

I work with vibration analysis on rotating equipment, and I am learning about ODS, and I am also a beginner at Ansys.

I drew an engine and a base, but very basic, just to try to simulate Ansys, I set up a project with modal analysis and random vibration.

Is it possible to manually enter the data (vibration collected with the accelerometer) from the mapping?

peteroznewman posted this 12 February 2018

If you fasten an accelerometer to the base of a structure and record a time history, you can apply that data as an acceleration load to the structure that is mounted on that base in a Transient Structural analysis.

If you compute the PSD from the accelerometer time-history data, you can input that PSD into a Random Vibration analysis.

You should also explore the Modal analysis and the Harmonic Response analysis for your sample structure.

If you are playing with SpaceClaim, try the Shell tool to hollow out a block to make a thin walled box.

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peteroznewman posted this 03 May 2018

ODS usually refers to taking accelerometer data at many points on a structure and using ODS software to map the accelerometer data to a very coarse representation of the geometry to visualize the vibration mode shapes and determine the frequencies of the structure.

ANSYS can simulate the vibration shapes of a structure that is subject to a harmonic excitation, it is called Harmonic Analysis. Here is my example of a bridge. A more typical example would be a machine with an out-of-balance rotor causing a harmonic load on the structure.

ODS refers to the continuous operation of the machine. ANSYS  Transient Structural can show this, but is more suited to show the transients say at start-up.  ANSYS Harmonic Analysis is better for steady state vibration.