negative effect of vibration to human

Redundant dynamic interactions will take form of undesirable effects like vibrations or noise [1]. Both vibrations and noise have negative impact on human safety and health. These effects may cause: a) balance disorder (motion sickness), b) neck and occiput area pain (connected with stressed back muscles preventing excessive movement of head caused by vibrations), common among professional drivers, These factors cannot be underestimated, because the consequences have unquestionable impact on human health and safety. Noise, vibration, and harshness (NVH), also known as noise and vibration (N&V), is the study and modification of the noise and vibration characteristics of vehicles, particularly cars and trucks. While noise and vibration can be readily measured, harshness is a subjective quality, and is measured either via "jury" evaluations, or with analytical tools that provide results reflecting human subjective impressions. Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. Kinetic energy is transformed to form of potential energy to be transformed once again to kinetic energy. This leads to the loop of cycle until excitation of this phenomenon [1]. The measurement of vibrations is affected by the number degrees of freedom of measured object. Mechanical system such internal combustion engine has a very large number of degrees of freedom. L. J. Sitnik, M. Magdziak-Tokáowicz, R. Wróbel, P. Kardasz
In order to cope with this problem and avoid the large number of calculations, interpolation functions are used to bring physical system to state in which the number of degrees of freedom is known. Components are divided in regard to mass. Components with lower mass are treated as deformable bonds, and those with larger mass are treated as mass points or rigid bodies. Vibroacoustic signal is often incorrectly identified with acoustic vibrations. This is caused by fact that the definitions of both vibroacoustic signal and