One of the best-known services Techno Fysica offers is measuring and analysing vibrations.
For this, thorough knowledge and experience, as well as a range of equipment is available.
We have single and multiple channel systems at our disposal for registration and analysis, and to date 16 or 32 parallel channels are becoming the norm rather than the exception.
Our knowledge and experience are applied to determine the state of the machinery, in order to test comfort requirements and, of course, to prevent and solve problems.
In case of problems to do with vibrations (and sound) the rule of thumb is that the problem needs to be recorded first, after which a suitable solution can be found based on influencing factors. We prefer to tackle the problems at the source, but options include adapting transmission path, changes in natural frequency, damping or even introducing passive tuned mass dampers. The best approach differs for each case and no two problems are alike, but years of experience, flexibility and creativity normally provide a solution.
The most practical and most widely-used sensors are accelerometers, but non-contact measurement with laser or inductive/eddy-current sensors is also possible. These would always be used in combination with other parameters that can be registered in parallel so correlations can be distinguished. Depending on your question the proper measuring method and further completion of the measuring programme and the subsequent analyses will be decided on.
Examples of this type of measurement are:
- Condition monitoring of machines and equipment (e.g. ISO 18436.2).
- Comfort-related questions, often in combination with sound measurements. This can, of course, be done on board of ships and yachts (ISO 6954) but also for offshore (Norsok), industry (ISO 2631) or, if necessary, for working conditions (EC guidelines).
- Testing on test beds or on location; we have abundant knowledge and experience in the field of combustion engines, obviously with the specialisation in marine propulsion and diesel generator set performance. All of this according to ISO or Class guidelines as set by, for example, DNV or Lloyd’s.
- Recording operational or modal movements, whether or not visualised in moving animations, so that movement is clearly shown per frequency or mode. Often this is done to support the investigation into the problem, but it can, of course, also be used to verify dynamic finite element calculations or to monitor degrees of freedom in resiliently mounted setups.
- Vibration measurement also serves as a resource when researching problems and damage, in cases where vibrations can be the source of the problem or indicate an underlying problem. It is often possible to establish the dominant source of the frequencies in the vibration spectra, after which possibilities to eliminate or dampen this source can be looked for.
- Investigating resonance is also a common issue in which mode shapes and finding the excitation source come together. After all, a resonance problem does not arise until there is not only a mode but also an excitation source.