# What is vibration isolation

### Damping and vibration control

Damping is essential for vibration isolation in construction. With a high loss factor, cork is an excellent damping tool that increases safety and comfort in buildings and infrastructures.

### What is attenuation?

Damping is the derivation of vibration energy in solid media and structures over time and distance. Similar to the absorption of sound in the air, damping occurs whenever there is some kind of friction that reduces movement and distributes energy.

The cushioning ability of each material is considered to beLoss factor and this represents the ratio between the energy dissipated and the energy remaining in the system during each cycle.

Damping is indispensable in construction to limit vibrations and ensure safety and comfort in buildings and infrastructures.

### Why is cushioning important?

Damping is a way of limiting vibrations and is essential for protecting the entire system.

This is the case with door or drawer springs, where the damping prevents vibrations when opening / closing, spares them and protects the system. On a larger scale, however, such as bridge decks, damping systems serve the same purpose.

Assuming there is a dynamic sinusoidal load that is stimulating a building structure or a structure with an exact frequency, what could happen? In theory, the movements would keep getting bigger and the structure would eventually collapse. It did so in 1940, a few months after its inauguration, with the Tacoma Bridge in the United States.

### E-book vibration isolation Acousticork

Damping is a way of limiting vibrations and it is essential to protect the entire system.

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### Permeability: mass, rigidity and damping.

The performance of an insulation system is determined by its permeability, i.e. the ratio between the energy introduced into the system and the energy exiting the system. The vibration damping material is selected taking into account the placement of the system's interference frequency in the isolation area. In addition, the damping volume of the insulation system determines the maximum permeability (fn) of the system. The peak value decreases with increasing damping.

• The dynamic response and permeability of a structure are essentially determined by its mass and stiffness properties, which are responsible for the energy remaining in the system, and by the damping, which determines the energy loss in the system.

Of these three properties, attenuation is the least understood and the most difficult to predict and measure. Mass and stiffness are easier to understand and measure because they can be determined using static measurements.

• Many vibration-related problems can be solved with a simple physical model, the so-called spring-mass system. If the mass is brought out of equilibrium by a brief external force, it has a natural frequency of f0. The range of this oscillation disappears over time based on the spring damping function, which is described as the mechanical loss factor ().

Insulation is responsible for this and can be measured by:

• vibration rate reduction in the resonance phase;
• Temporal variation in free oscillations;
• Spatial reduction of forced vibrations.

### Cork as a damping material

Due to its closed, cellular structure, which is filled with air, cork has a higher loss factor than rubber, which is essential for cushioning and the resulting energy dissipation. Our specific polymer formulations and the addition of cork with its unique compressibility and recovery properties reinforce the high loss factor of the material.

The Acousticork series for vibration isolation from Amorim Cork Composites offers solutions with an excellent compromise between damping and isolation.

The Acousticork series for vibration isolation from Amorim Cork Composites offers solutions with an excellent compromise between damping and isolation.

### Mechanical loss factor of the Acousticork range (π):

materialLoss factor (DIN 53513) *
Acousticork VC1001 0,15
Acousticork VC1002 0,13
Acousticork VC1003 0,16
Acousticork VC1004 0,16
Acousticork VC1005 0,10
Acousticork VC1006 0,14

* Depending on the temperature, frequency and load