Engineering, Energy, Transport AIC

Stepan BEREHULIAK – Postgraduate Student of Department of Desing Machine and Automotive Engineering, Lviv Polytechnic National University, (79013, 12 Stepan Bandera Str., Lviv, Ukraine, е-mail: Stepan.T.Berehuliak@lpnu.ua, https://orcid.org/0009-0005-6597-9752).

The paper investigates the influence of stiffness and damping on the oscillations of a spring-damper system under a given load (sprung mass). The stiffness determines the mass of the sprung part of a vehicle structure. The use of a damper in a typical configuration between the sprung and unsprung masses may, in some cases, help to attenuate vibrations, while in others, it may amplify them.
The aim of the experimental study is to empirically substantiate the rational parameters of the spring-damper system under a non-harmonic excitation of the oscillatory system by a force impulse of a given amplitude.
A laboratory test rig and the results of a factorial planned experiment are presented. A second-order regression equation in natural parameters was obtained. The regression model was analyzed with two factors – the sprung mass and the damping coefficient – while the stiffness coefficient was kept constant at three levels. For a stiffness coefficient of 3088 H/m and an excitation force impulse of 500 H applied to mass m2, the oscillation amplitude of the sprung mass of 100 kg with a damping coefficient of 300 H·s/m is 48 mm, and with a damping coefficient of 200 H·s/m – 47 mm. For a sprung mass of 50 kg and damping coefficient of 300 H·s/m, the oscillation amplitude of mass m2 is 88.9 mm, and with a damping coefficient of 200 H·s/m – 76.9 mm. Similarly, for a stiffness coefficient of 2745 H/m and excitation force impulse of 500 H, the oscillation amplitude of the sprung mass of 100 kg with a damping coefficient of 300 H·s/m is 55 mm, and with 200 H·s/m – 47 mm. For a sprung mass of 50 kg and damping coefficient of 300 H·s/m, the oscillation amplitude of mass m2 is 108 mm, and with 200 H·s/m – 85.9 mm.
With a decrease in the sprung mass, the oscillation amplitude increases. A decrease in the stiffness coefficient of the spring-damper system also results in an increase in the oscillatory impulse amplitude of the sprung mass. A reduction in the damping coefficient of the spring-damper system leads to a decrease in the oscillatory impulse amplitude of the sprung mass. This enables adaptive control of the sprung mass oscillations while maintaining the condition of a damped oscillatory response of the spring-damper system.

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