Module 7: Advanced Topics in Vibration Control
  Lecture 37: Active Constrained Layer
 

 

Table below describes the damping performances of viscoelastic materials, hard-damping alloys and active materials.

Table 37.1: Damping performance of VEM

Damping Material
Advantages
Disadvantages
Passive Damping Materials Viscoelastic
  • High Damping
  • Low weight Penalty
  • No external effort
    needed
  • Unsuitable for very low and high temperatures and at low frequencies
  • No controllability
Hard Damping Alloys
  • High temperature, high frequency operating range
  • No external effort needed
  • Relatively low damping
  • High weight penalty
  • High strain dependency
  • No controllability
Active vibration suppression Materials Piezoelectric, Magnetostrictive alloys or composites
  • Controlled blocking
    force generation
  • High or Moderate
    temperature, high
    frequency operating
    range
  • Low inherent damping in
    most operating range
  • External energy supply
  • Instability issues in control
Shape Memory alloys
  • Large strain
    applications
  • Lower controllability
  • Low frequency bandwidth
  • Needs either stress or temperature induced phase Transformation

The ACLD or hybrid system could be considered to be a fusion of purely active and purely passive damping. It retains the advantage of passive damping in terms of robustness and reliability while reducing the overall weight of the system and increasing the efficiency to attain high damping over a large frequency band.