Frequency Response and Modal Analysis

To understand why vibration can become or is a problem it is necessary to understand it’s characteristics. What frequency is the vibration, what amplitude is the vibration, what is the physical excitation of the vibration and what is the “shape” of the vibration.

The vibration shape is important because resonant behaviour prescribes a modal shape, for example the first mode of a flag pole would see it “vibrate” back and forth with the largest displacement at the top.  Often vibration occurs when a forced frequency excites a structural resonance.  Knowing the relationship and modal shape of the vibration allows mitigation solutions to be proposed and designed.

It is possible to determine an understanding of the vibration modal shape through physical measurement. However, even greater detail and understanding can be obtained through computer simulation and modelling.  Xi use COMSOL Multiphysics to model systems, which allows us to identify and visualise the frequency response of machinery for given frequencies.  By founding these virtual simulations with real-world measurements, Xi can develop these models with high levels of precision allowing fast, efficient and effective solution resolution.