Oscillation Damping

Oscillation Damping 

the artificial suppression of oscillations in mechanical, electrical, and other systems. It may be produced by an increase in attenuation; to this end dampers, such as pistons moving in a viscous medium, are installed in the system. Damping reduces the amplitude of the oscillations in the system, and if the quality factor of an oscillatory system is reduced to a value of 0.5, the oscillatory motion becomes aperiodic.

Figure 1. Diagram of oscillation damping in a mechanical system

Another method of oscillation damping consists in suppressing oscillations of a specified frequency ω by means of an auxiliary oscillatory system tuned to this frequency and developing a force equal to the value of the force that produces the oscillation but opposite in direction. Thus, in a mechanical oscillating system (Figure 1) that consists of a mass m₁ and a spring k₁ that is acted upon by an external force F = F₀cos ω, damping is produced by a damper consisting of a mass m₂ that oscillated on a spring k₂. When , the oscillations are damped, and the mass m₁ does not oscillate because at this frequency natural oscillations take place in the system k₂m₂, and the force of the spring k₂ acting on the mass m₁ balances the external force F. In the case of an electrical circuit damping is produced bv a suppression filter (Figure 2). At a frequency the oscillations in the circuit L₁C₁ are substantially reduced.

Figure 2. Diagram of oscillation damping in an electrical circuit L₁,C₁ (L is an inductance, and C is a capacitance) by means of an auxiliary circuit (suppression filter) L₂C₂

Damping plays an important role in instrument engineering in the quieting of indicator pointers, as well as in technology, when undesirable oscillations are present in machines, mechanisms, machine tools, and structures.

REFERENCE

Strelkov, S. P.Vvedenie v teoriiu kolebanii, 2nd ed. Moscow, 1964.

V. N. PARYGIN