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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.
here is the mass matrix, is the damping matrix, and are internal force per unit displacement and external forces, respectively. Using the extended mean value theorem , the Newmark- β {\displaystyle \beta } method states that the first time derivative (velocity in the equation of motion ) can be solved as,
Damping dissipates energy in the system, which reduces the vibration level which is transmitted at the natural frequency. The fluid in automotive shock absorbers is a kind of damper, as is the inherent damping in elastomeric (rubber) engine mounts. Damping is used in passive isolators to reduce the amount of amplification at the natural frequency.
The damping ratio provides a mathematical means of expressing the level of damping in a system relative to critical damping. For a damped harmonic oscillator with mass m , damping coefficient c , and spring constant k , it can be defined as the ratio of the damping coefficient in the system's differential equation to the critical damping ...
More commonly, for crystalline materials with low damping, a pulse propagation method is used. This method employs a wave packet whose length is small compared to the specimen. The pulse is produced by a transducer at one end of the sample, and the velocity of the pulse is determined either by the time it takes to reach the end of the sample ...
Dynamic modulus (sometimes complex modulus [1]) is the ratio of stress to strain under vibratory conditions (calculated from data obtained from either free or forced vibration tests, in shear, compression, or elongation). It is a property of viscoelastic materials.
This model is well-suited for modelling object with complex material properties such as nonlinearity and viscoelasticity. Packages such as MATLAB may be used to run simulations of such models. [1] As well as engineering simulation, these systems have applications in computer graphics and computer animation. [2]
Gypsum panel with constrained-layer damping. Constrained-layer damping is a mechanical engineering technique to suppress vibrations. Typically a viscoelastic or other damping material, is sandwiched between two sheets of stiff materials that lack sufficient damping by themselves. The result is that any vibration generated on either side of the ...