Mechanical Engineering
NVH Transmissibility Simulator
Examine transmissibility curves and vibration isolation efficiencies of a Single Degree of Freedom (SDOF) mass-spring-damper system subjected to harmonic base excitation.
Dynamic Model
SDOF System
Harmonic force
Critical Freq
r = 1.00
Resonance
Data Nodes
61 sampled
Realtime
Parameters
Damping Preset
Frequency sweep
Isolator Governing Equations
Transmissibility
TR = √[1 + (2ζr)²] / √[(1-r²)² + (2ζr)²]
Isolation Efficiency
Iso = Max(0, (1 - TR) × 100%)
Decibel Reduction
dB = -20 × log10(TR)
Resonance occurs at r = 1.0. Lower damping ratios result in larger peak responses.
Isolator is effective only when r > √2 (r > 1.41). At this frequency ratio, attenuation is positive.
Vibration Isolator Rig
Transmissibility
0.825TR
Vibration Isolation
17.5%
System Status
Isolation Active
Attenuation
1.7dB
Transmissibility Frequency Response
Frequency Sweep Data
| Freq Ratio (r) | Transmissibility (TR) | Vibration Isolation |
|---|---|---|
| 0.00 | 1.000 | 0.0% |
| 0.15 | 1.023 | 0.0% |
| 0.30 | 1.098 | 0.0% |
| 0.45 | 1.248 | 0.0% |
| 0.60 | 1.528 | 0.0% |
| 0.75 | 2.083 | 0.0% |
| 0.90 | 3.137 | 0.0% |
| 1.05 | 3.165 | 0.0% |
| 1.20 | 1.870 | 0.0% |
| 1.35 | 1.177 | 0.0% |
| 1.50 | 0.825 | 17.5% |
| 1.65 | 0.623 | 37.7% |
| 1.80 | 0.493 | 50.7% |
| 1.95 | 0.405 | 59.5% |
| 2.10 | 0.341 | 65.9% |
| 2.25 | 0.293 | 70.7% |
| 2.40 | 0.256 | 74.4% |
| 2.55 | 0.227 | 77.3% |
| 2.70 | 0.203 | 79.7% |
| 2.85 | 0.183 | 81.7% |
| 3.00 | 0.167 | 83.3% |