The Choice of Evaluation Vibration Car Security
Mechanical Engineering and Computer Science
In the presented material of the article the debatable question - a question of a choice of the field of mathematical modeling of system of vibration isolation of the car is considered. It is known that such a problem can be solved in the frequency and time domain. Since the primary vibration isolation system of the car has non-linear elements, the question arises: how does the solution of the linearized dynamic system in the frequency domain correspond to the data of calculations of the
... tions of the accepted indicators in the time domain? The problem is solved with a random kinematic perturbation from the road surface. Therefore, when working in the time domain, it is necessary to pre-select the method of statistical linearization from the known in practice design of automatic control systems.Four methods of statistical linearization, using which calculations were carried out in the frequency domain, are considered. For a similar dynamic system with its initial and statistically linearized nonlinear elements, calculations were carried out in the time domain. It is shown that the first method of statistical linearization is the most adaptive, according to the amplitude-frequency characteristics of the system. Such calculations were carried out for two surfaces corresponding to the cobblestone and dirt road at different speeds of the car.The analysis of the calculated amplitude-frequency characteristics was carried out for the "resonant" speed of motion, at which the greatest manifestation of the system nonlinearity takes place. When driving in this mode, the system significantly increases the probability of losing contact with the tire support surface. This violates the safety of the vehicle and the system is out of the vibration safety analysis area. Especially this phenomenon is observed when driving on a dirt road at a "resonant" speed. The final results of the calculations are separate-frequency and integral parameters. The latter do not give priority in the selection of the area of calculation, provided the safety of the vehicle.Thus, it can be concluded that the adequacy of the calculations in the frequency and time domain under really specified conditions of the vehicle on the corresponding road surface. However, testing of the problem to be solved, for example, by the eigenfrequency vector of a conservative system, is advisable to be carried out in the frequency domain.