JUSTIFICATION OF THE DESIGN AND PARAMETERS OF A BEARING SUPPORT WITH A LAYERED DAMPER FOR VIBRATION SUPPRESSION OF TECHNOLOGICAL MACHINE SHAFTS

Abstract

The reliability and operational durability of technological machines, including textile, cotton-processing, food-industry and metal-cutting equipment, are largely determined by the dynamic behaviour of their rotor–shaft systems. High-speed shafts are inevitably subjected to unbalanced and parametric excitations that, under conventional rigid bearing supports, lead to elevated vibration amplitudes, accelerated bearing wear and premature failure. The present paper substantiates an improved design of a rolling-bearing support equipped with a multilayered passive damper composed of three concentric viscoelastic elements: an outer rubber elastomer, an intermediate metallic mesh layer and an inner polymer-composite ring. A three-degree-of-freedom lumped-parameter dynamic model of the proposed support is developed, the corresponding equations of motion are derived and solved in the frequency domain, and the influence of the structural parameters on the amplitude–frequency characteristics and force transmissibility is analysed. A parametric optimisation procedure is proposed, yielding an optimum stiffness ratio of k₁/k₃ ≈ 4.0 and a total damping coefficient of about 3300 N·s/m for the considered class of machines. Comparative theoretical and experimental studies on a laboratory test rig demonstrated that the proposed layered support reduces the resonant vibration amplitude of the shaft by 78–85 % relative to a conventional rigid support and shifts the dominant resonance frequency outside the operating range. The mean relative deviation between the model and the measurements does not exceed 7.4 %, which confirms the adequacy of the proposed approach for engineering design.