The most common equipment vibration problems are often solved in industry without the use of specialty engineering. However, some noise and vibration problems require a more in-depth approach—one that involves a combination of computer simulation, specialty field measurements, and/or advanced data analysis techniques. When these more difficult and challenging dynamics problems arise, they call on Stress Engineering Services for expert consulting and field services.
Most field vibration troubleshooting starts with basic data collection via portable, hand-held signal analyzers that are easily moved around multiple locations in the vicinity of a vibration problem. Even complicated multi-channel vibration monitoring jobs often start with a field survey to identify the best locations for mounting sensors.
For some difficult vibration problems, long-term monitoring with multi-channel data acquisition emerges as a very powerful tool. Long-term monitoring allows our engineers to identify causal relationships between vibration characteristics and plant operating conditions. Taken together, this information often points to the source of a complex vibration problem.
EMA is often referred to simply as impact or shaker testing, and is used by our engineers in troubleshooting problems and for calibrating computer models. This is a traditional structural dynamics testing method that involves controlled loads applied to the test structure, and the analysis of the vibration (output) signals along with the measured loading (input) signals. The controlled loads are applied using shakers or impact hammers. This type of testing yields the three fundamental vibration parameters of all machines and structures: natural frequencies, mode shapes, and damping.
There are scenarios when traditional structural dynamics testing cannot be performed, for example, the equipment cannot be shut down, background noise levels are too high, and impact hammers are not practical or accessible, to name a few. The technique known as OMA may provide an alternative to traditional structural testing in such cases. This powerful technique is particularly well suited for process flow-induced vibration and civil/structural vibration—situations that are dominated by random vibration signals.
Our engineers use advanced data analysis and signal-processing techniques to reveal the features, patterns, and nuances in measured data that aid in understanding complicated dynamics problems. Our expertise in system dynamics ensures that state-of-the-art analysis capabilities are at the client’s disposal, from structural integrity monitoring and damage detection, to system identification using random output-only data.
When the results from computer models, such as finite element analysis (FEA), must be accurate to within a specified tolerance, our engineers use actual vibration and acoustic measurements from the field to fine-tune and calibrate models. Computer models calibrated to field measurements take much of the guesswork out of FEA to better simulate real-world behavior.