Vacuum Pump Vibration Isolation System Winter 2011 CONCEPTS’ EVALUATION REPORT Sponsoring Company: Edwards Vacuum LtdEdwards Vacuum Ltd. Contact Engineers: Mark Romeo Bree Edwards Academic Advisor: Dr. Dave Turcic Team Members: Ron Pahle Khoa T. Tran Duc M. Le Thanh Q. Nguyen

OVERVIEW I.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.STIFFNESS 1)AIRBAGS 2)SPRINGS 3)ELASTOMER 4)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

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.

BIBLIOGRAPHY 1.John C. Snodon, “Vibration Isolation: Use and Characterization” Justin Matthew Verdirame, “Structural Vibration damping Using Lightweight, Low-wave-speed Media” Bruno de Marneffe, “Active and Passive Vibration Isolation and Damping via Shunted Transducers” Baker, Vibration Isolation Clarence W. de Silva, “Vibration Damping, Control and Design”. 2010