Operational modal analysis
In operational modal analysis (OMA), only the output of a structure is measured using the ambient and operating forces as unmeasured input.
OMA is used instead of classical modal analysis for accurate modal identification under actual operating conditions, and in situations where it is difficult or impossible to artificially excite the structure.
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 OMA, these forces, which would produce erroneous results in classical modal analysis, are instead harnessed as input forces. As OMA can be performed in situ during normal operation, set-up time is reduced, and downtime can be eliminated.
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.