Vacuum Pump

Vibration Isolation System

Winter

2011

CONCEPTS’ EVALUATION REPORT

Sponsoring Company: Edwards Vacuum Ltd.

Contact Engineers: Mark RomeoBree Edwards

Academic Advisor:Dr. Dave Turcic

Team Members:Ron PahleKhoa T. TranDuc M. LeThanh Q. Nguyen

OVERVIEWI. INTRODUCTION

A. PASSIVE ISOLATION

B. ACTIVE ISOLATION

C. SEMI-ACTIVE

ISOLATION

II. SOLUTIONS

A. COMPOUND MASS

SYSTEM

B. DAMPING OF LOW-

WAVE-SPEED MEDIA

C. STIFFNESS1) AIRBAGS2) SPRINGS3) ELASTOMER4) CORK

III. EVALUATION

IV. CONCLUSION

V. BIBLIOGRAPHY

I. INTRODUCTION

A. Passive vibration isolation is implemented by proper structural design to make sure the optimal dynamics properties are achieved.

B. Active vibration isolation is performed by using feedback control to generate a controlled force

compensating the vibration source.

C. Semi-active vibration isolation seeks to control the damping and/or stiffness dynamically instead of actuator’s force.

II. Solutions

A. COMPOUND MASS SYSTEM

A. COMPOUND MASS SYSTEM

A. COMPOUND MASS SYSTEM

B. LOW-WAVE-SPEED MEDIA

B. LOW-WAVE-SPEED MEDIA

B. LOW-WAVE-SPEED MEDIA

C. STIFFNESS

1) AIRBAGS More expensive

High performance at very

low resonance frequency

Can be actively controlled

2) SPRINGS Low resonance frequency

Susceptible to corrosion

3) ELASTOMER• Drifting effect (15%

deflection)

• Perform better in shear

mode

4) CORK High compressive load

High internal damping

Cheap and long life service

Combined with neoprene

gives large deflection.

BIBLIOGRAPHY1. John C. Snodon, “Vibration Isolation: Use and Characterization”. 19792. Justin Matthew Verdirame, “Structural Vibration damping Using Lightweight, Low-

wave-speed Media”. 20043. Bruno de Marneffe, “Active and Passive Vibration Isolation and Damping via Shunted

Transducers”. 20074. Baker, Vibration Isolation. 19755. Clarence W. de Silva, “Vibration Damping, Control and Design”. 2010