1. Characterization of Omega Pod
Measurement Report on Vibration Isolation of Omega Pod
Department of Physics, University of British Columbia, Vancouver PI: Dr Yan Pennec
Student: Vincent Wong

2. SolidWorks model – Omega
Suspended by 6 isolators (Model #)
Volume: m3 Density: kg/m3 Mass: E4 kg %Concrete: 91.5%
Young Modulus: 4.45E10N/m2 Poisson Ratio: 0.17

3. Concrete Block Properties Deduction from Threshold Pressure
Isolator Dimension
Chamber Diameter: 15.7in
Total Effective Area: in2 * 6isolators
Threshold Pressure: psi
Threshold Supporting Force: lbf
Equivalent to N
Measured Mass: kg
Measured Density: kg/m3

4. Experiment Protocol - Slab Excitation
Reference Accelerometer
Data Point

5. Slab Excitation – Acceleration Amplitude z-axis damping for the slab
Time Constant ~124ms
y = A1*exp(-x/t1) + y0
y0= ms-2
A1= ms-2
t1= s

6. Slab Excitation – Average PSD in z-axis (0-1kHz)

7. Slab Excitation – Average PSD in z-axis (200-450Hz)
Twisting
Flapping
Support

8. Modal Resonance - Twisting Mode
Measured 210Hz
FEA 212Hz
(1st mode in FEA)

9. Modal Resonance- Bending Mode
Measured 293Hz
FEA 291Hz
(2nd mode in FEA)

10. Modal Resonance - Flapping Support Mode
Measured 385Hz
FEA 377Hz
(4th mode in FEA)

11. Modal Resonance - Measured mode @ 396Hz FEA simulation @ 401Hz
(6th mode in FEA)

12. Modal Resonance - Measured mode @ 412Hz FEA simulation @ 415Hz
(8th mode in FEA)

13. Damping by Isolators – x-axis acceleration amplitude
Time Constant ~8.69s
Natural Frequency ~0.81Hz
y = A1*exp(-x/t1) + y0
y0= E-4 ms-2
A1= ms-2
t1= s

14. Damping by Isolators – y-axis acceleration amplitude
Time Constant ~11.5s
Natural Frequency ~0.96Hz
y = A1*exp(-x/t1) + y0
y0= ms-2
A1= ms-2
t1= s

15. Damping by Isolators – z-axis acceleration amplitude
Time Constant ~1.75s
Natural Frequency ~1.29Hz
y = A1*exp(-x/t1) + y0
y0= 7.8E-4 ms-2
A1= ms-2
t1= s

16. Transfer Function in z-axis - Isolators

17. Transfer Function in z-axis – Room Isolation

18. Seismic Vibration in z-axis – velocity PSD open room

19. Seismic Vibration – velocity PSD closed room (1 hour run)

20. Sound Pressure Level – closed room

21. Sound Pressure Level – Excited
24Hz
40Hz
30Hz

22. Acoustic Resonance Assumption: speed of sound = 350m/s
Expected Resonance Mode:
3.5m -> ~47Hz
3.8m -> ~43Hz
4.6m -> ~38Hz
5.2m -> ~33.7Hz
5.8m -> ~30.2Hz
6.0m -> ~29.2Hz
6.9m -> ~25.4Hz