Operational modal analysis OMA

Operational Modal Analysis (OMA)

Operational Modal Analysis (OMA) is used instead of classical modal analysis for accurate modal parameter identification of structures under actual operating conditions, and in situations where it is difficult or impossible to artificially excite the structure.

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In Operational Modal Analysis (OMA), only the output of a structure is measured using the natural ambient and operating forces as unmeasured input.

Many civil engineering and mechanical structures are difficult to excite artificially due to their physical size, shape or location. Civil engineering structures are also loaded by ambient forces such as the waves against offshore structures, the wind on buildings, and traffic on bridges, while mechanical structures such as aircraft, vehicles, ships and machinery exhibit self-generated vibration during operation.

In Operational Modal Analysis, these forces, which would produce erroneous results in classical modal analysis, are instead harnessed as input forces. As Operational Modal Analysis can be performed in situ during normal operation, setup time is reduced, and downtime can be eliminated.

System suggestion

Operational modal analysis system overview

For an integrated, easy-to-use modal test and analysis system, use BK Connect® Time Data Recorder for geometry-guided data acquisition, and then transfer data to PULSE Operational Modal Analysis software for analysis and validation.

To achieve the optimal OMA solution, you can select from Brüel & Kjær’s complete measurement and analysis chain including accelerometers, LAN-XI data acquisition hardware and measurement and post-processing software. 

Video: Brüel & Kjær Operational Modal Analysis

Webinar: Operational Modal Analysis – Modal Parameter Identification Under Operating Conditions

The webinar in the video below will:

  • Give an introduction to OMA;
  • Provide guidelines for when to use OMA instead of CMA and vice versa;
  • Show typical application examples of OMA for civil engineering and mechanical engineering structures;
  • Explain how OMA can be used for Structural Health Monitoring (SHM).

Niels-Jørgen Jacobsen
Product Manager - Structural Dynamics Solutions