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Damping capacity is a mechanical property of materials that measure a material's ability to dissipate elastic strain energy during mechanical vibration or wave propagation. When ranked according to damping capacity, materials may be roughly categorized as either high- or low-damping.
The effect of varying damping ratio on a second-order system. The damping ratio is a parameter, usually denoted by ζ (Greek letter zeta), [7] that characterizes the frequency response of a second-order ordinary differential equation. It is particularly important in the study of control theory. It is also important in the harmonic oscillator ...
The Q factor is a parameter that describes the resonance behavior of an underdamped harmonic oscillator (resonator). Sinusoidally driven resonators having higher Q factors resonate with greater amplitudes (at the resonant frequency) but have a smaller range of frequencies around that frequency for which they resonate; the range of frequencies for which the oscillator resonates is called the ...
The logarithmic decrement can be obtained e.g. as ln(x 1 /x 3).Logarithmic decrement, , is used to find the damping ratio of an underdamped system in the time domain.. The method of logarithmic decrement becomes less and less precise as the damping ratio increases past about 0.5; it does not apply at all for a damping ratio greater than 1.0 because the system is overdamped.
The ratio of the loss modulus to storage modulus in a viscoelastic material is defined as the , (cf. loss tangent), which provides a measure of damping in the material. tan δ {\displaystyle \tan \delta } can also be visualized as the tangent of the phase angle ( δ {\displaystyle \delta } ) between the storage and loss modulus.
Acoustic attenuation in many metals and crystalline materials is frequency-independent, namely =. [10] In contrast, it is widely noted that the η {\displaystyle \eta } of viscoelastic materials is between 0 and 2.
The impulse excitation technique (IET) is a non-destructive material characterization technique to determine the elastic properties and internal friction of a material of interest. [1] It measures the resonant frequencies in order to calculate the Young's modulus , shear modulus , Poisson's ratio and internal friction of predefined shapes like ...
Relative damping capacity of various metals [15] Materials Damping capacity † Gray iron (high carbon equivalent) 100–500 Gray iron (low carbon equivalent) 20–100 Ductile iron: 5–20 Malleable iron: 8–15 White iron: 2–4 Steel: 4 Aluminum: 0.47 † Natural log of the ratio of successive amplitudes