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CLD Estimator

Estimate composite system loss factor for free-layer and constrained-layer damping treatments.

Structural damping treatments reduce vibration amplitude and settling time in optomechanical mounts, mirror cells, and breadboard substructures. This tool estimates the composite system loss factor η_c for two damping configurations. Free-Layer Damping bonds a viscoelastic material (butyl rubber, neoprene, or Sorbothane) directly to the base structure; the RKU equation computes η_c from the modulus ratio and thickness ratio of the two layers. Constrained-Layer Damping (CLD) sandwiches a soft viscoelastic core between the base and a stiff constraining layer (e.g., steel over 3M ISD-112 over aluminum), forcing shear in the core under flexural vibration; η_c is estimated via the Kerwin shear parameter model. Outputs include composite loss factor, quality factor Q, and mass increase relative to the bare base structure.

Free-Layer Damping
Layer Ratios
Thickness ratio (n = h₂/h₁)
2.0000
Modulus ratio (e = E₂/E₁)
1.00e-4
Performance
Composite loss factor (η_c)
0.00246
Quality factor (Q)
405.7
Mass increase
30.7692%
Improvement over bare
8.2157×
Abridged Optics — CLD Estimator v1.0Free layer: RKU equation. CLD: Kerwin shear parameter model.

All information, equations, and calculations have been compiled and verified to the best of our ability. For mission-critical applications, we recommend independent verification of all values. If you find an error, please let us know.