Modal Analysis and Operating Deflection Shape Services:
The science and art of experimental modal and ODS techniques come together to provide a picture of equipment behavior identifying faulty operation. Complex equipment problems often times can be easily demonstrated using graphical animation of the equipment and supporting structure. Experimental modal analysis provides a representation of equipment performance over a range of frequencies; some of which may be directly related to the problem of machine performance. Operating deflection shape analysis provides a similar result but differs in that the analysis data is acquired during normal machine operation. While theoretical analysis can provide an excellent model of behavior, it is very difficult and time consuming to create a model that exactly depicts the true operating environment as shown by experimental results.
Experimentally derived frequency response, damping factors, and mode shapes of a structure have successfully led to:
- Remediation of system performance problems caused by premature component failure and fatigue failure
- Prediction of a structure’s (or component of) overall dynamic behavior and its influence on the overall system
- Environmentally induced variation in machine performance
- Correlation of FEA model to experimental results
ETS maintains an inventory of state of the art test equipment such as five different size modal hammers, multichannel spectrum analyzers, a complete array of triaxial accelerometers and a complete set of support equipment such as proximity probes, shaft sticks, laser tachs, long cabling, and accelerometer mounting systems.
A typical approach to on-site testing consists of defining the test objectives and test protocol followed by model generation, and data acquisition. Test results are viewed on site to ensure data integrity and to add immediate insight into the problem at hand (not necessarily the solution!).