• TRANSPORT. SAFETY AND ECOLOGY. LOGISTICS AND MANAGEMENT

    THE NOISE FROM VEHICLES AND TRANSPORT FLOW

    Trans Motauto World, Vol. 2 (2017), Issue 1, pg(s) 19-20

    Increases in road traffic lead to the expansion of areas of the acoustic discomfort, and the noises from vehicles acquire social importance. The noise as a set of sounds is characterized qualitatively and quantitatively by two main indicators: the sound pressure or intensity level, which have different effect on the human body. In addition, in terms of the effect on the human body, the prefence is given to the noise equivavlent level. The study of the noise equivalent level can be carried out in two ways. The first one consists in fact that at a given moment of time, at any point in space, there are summarized the noise level or sound energy intensity from all radiation sources, but another way implies summarizing the selected sound energy sources during a certain time period. So, in order to determine the noise equivalent level of one vehicle during that time period, which is required for passing a certain section, it is necessary to know those laws, which characterize traffic conditions and the calculated changes of the noise level in these conditions.

  • MATHEMATICAL DESCRIPTION OF VIBRO-ACOUSTIC PROCESSES OF INTERNAL COMBUSTION ENGINE

    Machines. Technologies. Materials., Vol. 9 (2015), Issue 9, pg(s) 24-25

    An internal combustion engine is considered as a material body, which characterized by inertial, elastic and dissipation properties, which are impacted from various forces. Oscillatory motion of a material body occurs in accordance with spectral characteristics of force and frequency responses of the system. The outer surface of the engine generates acoustic energy and causes mechanical noises.

    The paper dwells on determining acoustic energy in accordance with the acoustical radiation rate if the radiation coefficient of the object observed is known. Also, the sound of the engine is presented as a sum of its separate acoustic powers, and there is determined the acoustic radiation coefficient of the engine for the entire surface, by using the acoustic radiation coefficient of each surface. Simultaneously, there is determined the vibro-energy distribution in the engine design, the assessment of which is made by means of the energy-transfer coefficient, which generates the frequency responses of vibro-acoustic parameters.