Operating Deflection Shape (ODS) Analysis

Why we use ODS ?

Understand the motion to help in design modificationInvestigate looseness, Soft Foot, Unbalance, Misalignment

What is ODS readings ?

Single Channel reading

Using accelerometer & tachometer

"Provide phase data at the running speed only"

Two Channel reading

Cross-phase readings using two accelerometers

"Provide phase data at multiple frequencies"

Difference between ODS and Modal Analysis ?

• ODS involves measuring the relative vibration amplitude and phase around the machine or structure and then visualizing the physical movement at the running speed.

"Test take place while machine is running"

• Modal analysis involves exciting a structure with a known force and measuring the response.

"Test could take place while machine is not running"

Brief : ODS reveals the relative motion between components of a machine or different points on a structure, As the animations of the deflection shapes help visualize the problem.