Activities

Vibration control

PASSIVE AND ACTIVE VIBRATION CONTROL SYSTEM

Vibrations are all around us and are increasingly linked to machine restrictions, whether this be the conventional limitation of machine performance (e.g. printing resolution) and machine reliability (fatigue and wear), or more sophisticated phenomena like chatter (machine tool instability) or control-flexibility interaction.

If you have an issue with vibration, we will visit your site and carry out a diagnostic procedure so that we understand the origin of the problem. We will then propose active or passive solutions and evaluate the expected level of performance. After we have installed your solution, we offer an ongoing performance and monitoring service.

Our field of application for vibration reduction devices is wide-ranging:

  • Chatter avoidance, surface finish improvement, noise reduction in machine tools
  • Compressor noise reduction in the energy sector
  • Prevention of leaks and fatigue reduction in piping
  • Flutter control, comfort improvement, and fatigue
  • Reduction in civil engineering
  • Fatigue and noise reduction in wind energy
  • Graving quality and accuracy improvement in microelectronics and microlithography machines
  • Printing quality, photo paper surface finish improvement in the paper industry

Examples of applications

1

MACHINE TOOL CHATTER CONTROL

Chatter vibrations limit the productivity of heavy-duty milling and turning processes by reducing the maximum cutting depth. Chatter is a self-exciting phenomenon that can be reduced by increasing the structural damping of the machine critical modes. Several custom-made Active Damping Devices (ADD) have been developed by Micromega to improve the technical capacity of customers’ machines. Compared to passive Tuned Mass Dampers (TMD), ADD experience a lower weight and are insensitive to machine frequency changes.

2

Tuned mass absorber for noise cancellation in wind turbine

Wind turbine Tonalities are sounds at discrete frequencies peaking above broadband noise. While the acoustic power associated with them is rather low, these can be very annoying and therefore, in their presence, a penalty is placed on target maximum broadband noise levels (up to -6dB). This then has an impact on the maximum blade velocity, hence the generated power (up to -30%). TMD Sound reduces turbine tonalities by preventing the vibration generated by the gearbox from reaching the emission areas (tower, blades, etc.). It consists in passive Tuned-Mass Absorbers (TMA) mounted on the gearbox torque arms. At the tuning frequency, the vibration produced by the gearbox is transferred into the tuned mass absorber rather than in the tower, hence the avoidance of sound generation. TMAs have an absorption bandwidth of a few hertz and can be tuned to any frequency between 50Hz and 350Hz, addressing most of the tonalities generated by the first and second stages of a gear-box.

3

Tuned mass damper pipe

TMD Pipe (TMD stands for Tuned Mass Damper) is a passive damper for the reduction of vibrations in piping systems and is composed of a mass, springs and dampers. Functional principle: the TMD tuned to the resonance of the piping system increases the damping significantly, thus reducing the resonant amplitudes. TMD Pipe has been specifically developed because conventional vibration reduction methods have significant deficits. Conventional absorbers and snubbers require rigid abutment. As a purely mechanical structure TMD Pipe does without electrical components so that it can easily be used in hazardous areas. Moreover, it requires no external power supply. This makes it more reliable, during earthquakes, for example, where full operation is required even during power failure. TMD Pipe has been specifically developed for industrial use in facilities such as those within the chemical industry or in power plants. All components have increased corrosion protection. In addition, it operates reliably even under rough and changing environmental conditions.

4

Sound reduction in wind turbines

One actively controlled absorber ADD Sound is mounted at each torque support together with a small control cabinet in the nacelle. Tonal sound is cancelled over the entire range of speed.

Advantages:

  • Broadband and multi-RPM tonality cancellation
  • Less design space needed (compared to passive TMD Sound)
  • Can be retrofitted