Storage modulus damping material

How is damping characterized in a viscoelastic material?

The damping of a viscoelastic material is typically characterized using dynamic mechanical analysis (DMA). The output from the tests provide the complex modulus (storage and loss) as shown in a sample graph to the right where ′ is the storage modulus and ′′ is the loss modulus, both as a function of frequency.

What are the characteristics of a damping material?

The characteristics of the damping material are reflected in the linear complex modulus E * (f) at a given oscillation frequency f, characterised by its real and imaginary parts: the storage and loss moduli E ′ and E ″, and their ratio E ″/ E ′, usually referred to as the loss factor tan δ with δ the phase angle of E * 3.

What is the ratio of loss modulus to storage modulus?

The ratio of the loss modulus to the storage modulus is defined as the damping factor or loss factor and denoted as tan δ. Tan δ indicates the relative degree of energy dissipation or damping of the material.

Why does the storage modulus of damping material decrease with temperature?

The storage modulus of the damping material decreases with the increase of temperature. The reason is that when the temperature is low, the damping material is in a glass state, but as the temperature increases, the material changes from a glass state to a rubber state and becomes a rubber state when the temperature is high.

What is storage modulus (E) in DMA?

Generally, storage modulus (E') in DMA relates to Young’s modulus and represents how flimsy or stiff material is. It is also considered as the tendency of a material to store energy .

What is material internal damping?

However, damping materials and their applications are one of the most effective technical means to suppress vibration and noise [2, 3, 4, 5]. Material internal damping is the energy loss associated with microstructural changes . Among them, the viscoelastic material has a high loss factor, but its own elastic modulus is too small.