Levelmount_Machine_Mounts

31 In general  In static equilibrium, the static load is balanced by the sum of all reaction forces.  In dynamic equilibrium, the accelerated mass results in an additi- onal frequency-dependent force, called inertia. The effect of inertial forces on the vibration system is determined by the tuning ratio. If the tuning ratio η < 2, excitation and inertial forces add up. If the tuning ratio η > 2, the inertial forces are phase-inverted to the exciting force. From a tuning ratio of 2, the resulting force will be smaller than the exciting force (see figure 5). Effects Natural frequency and damping determine the dynamic properties of a vibration element.  The natural frequency is a function of deflection (s). In the linear region of the spring characteristic curve, the following applies by approximation f e (Hz) = 5 / s (cm). The wide area of linearity achieved by EFFBE LEVELMOUNT supports is due to the special design of the elastomer body.  Damping describes the energy loss that the vibratory system undergoes by internal friction. This produces damping forces that reduce the vibration amplitudes at a tuning ratio of up to η = 2 . If the tuning ratio is higher, the vibration amplitudes are influenced only marginally by damping. Damping is effective only up to η = 2, and so depends on the excitation frequency. Frequency- dependent damping is achieved with the patented pneumatic spring SLM-D. During shock absorption, damping reduces the amplitude with a tendency to poorer shock absorption at increased damping. Dynamic properties Long-term effects A pre-condition for a consistent isolating effect is the long-term elasticity of the elastomer material. Composite or reclaimed materials are pressed together by static and dynamic loading and lose their elasticity. Environmental influences may cause elasticity loss. In this respect, above all, a high ozone resistance is required. EFFBE elastomer materials are characterised by a low compres- sion set according to DIN ISO 815 and a high ozone resistance. This ensures the necessary long-term durability. Literature DIN EN 1299 Mechanical Vibration and Shock Vibration Isolation of Machines Information for the application of source isolation VDI 2062 Vibration Isolation Part 1 Terms, definitions and methods Part 2 Isolation elements VDI 3833 Dynamic damper and dynamic vibration absorber Part 1 Dynamic damper Terms, characteristics, implementation, application Part 2 Dynamic vibration absorber Terms, characteristics, implementation, application Figure 5 Tuning ratio η < 2 Tuning ratio η > 2 1 0 -1 1 0 -1 1 0 -1 1 0 -1 Exciting force Exciting force Inertial force Inertial force resulting force resulting force