Operational Modal Analysis

Operational Modal Analysis is a complementary technique to traditional modal analysis methods and is based upon measuring only the responses of test structures.

The technique enables the testing of structures such as running cars, airplanes, windmills, etc., that are impossible or difficult to excite by external forces, owing to boundary conditions or physical size.

Data quality is also improved because the data represents real operating conditions - measurements are performed with true boundary conditions guaranteed. Current force and vibration levels are used, ensuring that the structure's dynamics, which can change for different operating conditions, are always measured correctly.

Operational Modal Analysis also saves time as input forces are not measured, allowing many of the time-consuming, practical issues related to modal testing to be ignored. Furthermore, no test rigs are needed for in situ measurements, and setup time is short as only accelerometers are used in testing. Structures can also be tested in situ under operation, avoiding interference with or interruption of their daily use.

Brüel & Kjær Operational Modal Analysis is optimised for use with PULSE, the real-time, multi-analysis analyzer platform, along with Modal Test Consultant Type 7753, but is also effective as a stand-alone application. This is because geometry and measurement data can be imported into the application from ASCII or UFF files. The ActiveX™ control standard is also supported, allowing you to import many different types of data from other software applications under the same standard, for example, Word, Excel, MATLAB and PULSE.