This simulator mounts a rotating machine on four springs and dampers above a receiving foundation. Change the forcing frequency, supported mass, combined mount stiffness, damping ratio and force amplitude, and compare machine displacement with the force that passes through the mounts.
• A 3D machine with an eccentric rotor supported on four resilient spring mounts with viscous dashpots, resting above a receiving foundation with a transmitted-force indicator. • Controls for forcing frequency, supported mass, combined mount stiffness, damping ratio and force amplitude. • Six readouts: mount natural frequency, frequency ratio, force transmissibility, transmitted force peak, machine displacement and static sag. • Curves & measurements, two guided experiments with a verification bench, and Learn & assess lessons and a quiz.
The mounts have a natural frequency ωn = √(K/M), and the frequency ratio is r = ω/ωn. Force transmissibility for a single degree of freedom is T = √[(1 + (2ζr)²) / ((1 − r²)² + (2ζr)²)]. At and below r = √2 the transmissibility is near or above one, so the mounts do not help and may amplify force at resonance. Only above r = √2 does the transmitted force drop below the applied force.
Damping is a tradeoff: it limits the resonance peak, but it reduces isolation at high frequency. Static sag, Mg/K, tells you how far the machine compresses the mounts under its own weight.
The model has one vertical degree of freedom on a rigid base and gives the steady harmonic response, with no startup transient, rocking motion, structural radiation or manufacturer selection. Force amplitude is constant rather than tied to a fixed unbalance mass. Motion is enlarged up to 60 times but bounded so the mounts stay visible, and time is slowed 10 times.
It is the ratio of the force transmitted into the foundation to the force applied by the machine. A value below one means the mounts are reducing the force reaching the structure.
Transmissibility falls below one only when the forcing frequency exceeds about 1.41 times the mount natural frequency. Below that, the mounts do not reduce transmitted force and may increase it near resonance.
More damping reduces the resonance peak but raises transmissibility at high frequency ratios. Choosing damping is therefore a compromise between crossing resonance and isolating high-frequency vibration.
No. It is a one-degree-of-freedom steady-state teaching model and does not cover rocking modes, startup transients, structural radiation or product selection.