Vibration (Resonance)

It refers to an event in which an object repeatedly changes its position up and down, left and right, etc. with time around a certain reference position. A periodic vibration is one in which the same state is repeated at regular intervals, while an irregular vibration is one in which the magnitude and period at any given time are unpredictable. The vibration level is defined as the vibration acceleration level calculated from physical quantities plus sensory corrections, and is expressed in decibels (DB) (Resonance is a phenomenon in which, when a periodic force is applied to a vibrating object such as a pendulum from the outside, the closer the frequency is to the natural frequency of the object, the more effectively the work done by the external force is absorbed and the object vibrates more violently. The closer the frequency to the natural frequency of the object, the more effectively the work done by the external force is absorbed and the more violent the vibration of the object becomes.)