Viscoelastic Properties

What Are the Viscoelastic Properties?

Viscoelastic materials are added to structures and plates in order to avoid large vibrations, espciallly around resonant frequencies. The properties of these materials are the Young’s modulus (E(ω)), the loss factor (η(ω)) and shear modulus (G(ω)). These parameters are frequency and temperature dependent. Damping materials have application in structural vibration (vibration fatigue), building acoustics, and noise control.

Depending on their nature, viscoelastic materials are tested following four kind of assembly:

• Homogeneous beam,
• Single side treatment,
• Double side treatment,
• Sandwich beam treatment.

How to Measure the Viscoelastic Properties?

Equipment: Oberst Beam System
Standards: ASTM E756, ISO 6721-3
Method: Standard Test Method for Measuring Vibration – Damping Properties of Materials [1, 2]
Parameters:

• E(ω) – Frequency dependent Young’s modulus (Pa)
• η(ω) – Frequency dependent damping loss factor
• G(ω) – frequency dependent shear modulus

References

[1] ASTM E756-05, “Standard Test Method for Measuring Vibration-Damping Properties of Materials”.

[2] L. Jaouen, J.L. Wojtowicki, and R. Panneton, “New approach for the measurement of damping properties of materials using the Oberst beam,” Rev. Sci. Instrum. 75, 2569 (6 pages) (2004).

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