Modulation effect of vibration frequency of an unsprung heavy machine under the variable road adhesion conditions

• Autorzy: Chwastek S.
• Języki publikacji: EN

Abstrakty

EN

Mobile heavy machines as unsprung vehicles exhibit low dissipation ability, hence the ride even at low speeds may give rise to intensive vibration. Particularly dangerous situations occur when the road wheels break away from the road surface due to the ’galloping’ effect, being the result of excited vertical and angular vibration of the machine frame in the vertical plane of symmetry. That implies a major restriction on the ride velocity, which negatively impacts on the machine performance. Vibrations thus produced are mostly in the low-frequency range and hence energy dissipation in tyres will reduce the vibration intensity in a minor degree only. The motion of tired wheels will always involve some slipping. While investigating the feasibility of increasing the efficiency of the vibration reduction systems, one ought to take into account the variable adhesion of road wheels due to different dynamic loading acting on the vehicle axles during the ride. Observations of unsprung machines during the ride suggest the occurrence of self-excited vibration. Mobile machines constitute dynamic systems, which can be governed by nonlinear, sometimes non-stationary differential equations of motion. Their stability also depends on intensity of external vibrations. This study investigates the motion of unsprung mobile machines, taking into account the dynamic processes in the driving system under the conditions of the variable adhesion of road wheels. The model of interaction between a tired wheel and the terrain takes into account the relationship between the road wheel adhesion factor and the slipping action. Mathcad supported by Matlab-Simulink and in the frequency domain – simulations in the time domain. The purpose of the simulation procedure was to find the causes of the vibration modulation frequency and determine the conditions triggering the occurrence of self-excited vibrations. Simulations are supported by the analysis of motion stability.

Słowa kluczowe

EN

mobile heavy machines; unsprung vehicles; galloping effect; adhesion factor; slipping action; frequency modulation of vibration

• Wydawca: Łukasiewicz Research Network - Institute of Aviation ; European Science Society of Powertrain and Transport KONES Poland ; Wydawnictwo Instytutu Technicznego Wojsk Lotniczych
• Czasopismo: Journal of KONES
• Rocznik: 2013
• Tom: Vol. 20, No. 4
• Strony: 55--62
• Opis fizyczny: Bibliogr. 6 poz., rys.

Twórcy

autor

Chwastek S.

• Krakow University of Technology Institute of Machine Design Jana Pawła II Avenue 37, 31-864 Krakow, Poland tel.: [phone], fax: [phone]

Bibliografia

• [1] Andrzejewski, R., Awrejcewicz, J., Nonlinear Dynamics of a Wheeled Vehicle, Springer Science + Business Media, Inc., 2005.
• [2] Chwastek, S, Michałowski, S., Optimal Stabilization of Equipment in Unsprung Mobile Machines, The Archive of Mechanical Engineering, Vol. LV, No. 3, pp. 227-236, 2008.
• [3] Grzegożek, W., Modelowanie dynamiki samochodu przy stabilizującym sterowaniu siłami hamowania, Monografia 275, Wydawnictwo Politechniki Krakowskiej, Kraków 2000.
• [4] Koutny, F., Geometry and Mechanics of Pneumatic Tires, Zlin 2007.
• [5] Mitschke, M., Antrieb und Bremsung, Dynamik der Kraftfahrzeuge, Springer-Verlag, Berlin, Heidelberg, New York 1987.
• [6] Prochowski, L., Mechanika ruchu. Pojazdy samochodowe, WKŁ, Warszawa 2005.