The paper presents results of experimental investigations of the influence of temperature on the effectiveness of passive vibration isolation. Two types of viscoelastic materials (butyl rubber and bituminous material) were tested. In the performed vibration analysis, the Oberst beam made out of aluminum alloy with a damping material in a Free Layer Damping (FLD) configuration was used. The experimental modal analysis was performed using the Unholtz-Dickie UDCO TA-250 vibration system. To investigate the influence of temperature on the effectiveness of passive vibration isolation, an isothermal cooling chamber (using Peltier cells) was designed and constructed. The tests were carried out in a wide frequency range from 40 Hz to 4000 Hz, at a constant sweep rate, in a temperature range from −2 °C to 22 °C. Miniature piezoelectric acceleration sensors were used to determine the acceleration of the beam and the exciter head. The analysis of accelerations of both the object and the shaker head allowed for the determination of a Frequency Response Function (FRF) for the beam. The course of FRF was used to determine the resonance frequencies and the vibration amplitudes of the beam damped with bituminous material and butyl rubber at various temperatures. The loss factor η, calculated for each resonance using the generalized half-power method (n-dB method), was used as an indicator of damping intensity. The research results presented in this work (important from scientific point of view) also have utilitarian significance and can be used in the design of more quiet and comfortable motor vehicles, railway wagons and aircraft structures.

This study presents results of an experimental investigations of the materials used in passive damping vibrations. The main purpose of this paper was to examine the damping properties of selected viscoelastic materials (VEM), using the modal analysis. In presented analysis three configurations of specimens were considered. At first, the separated steel beam was analyzed. As results of this analysis, the frequencies and amplitudes of the beam during resonance were obtained. In next part of the work the modified specimen was investigated. In this modification the bitumen-based material (as a damper) was fixed to the surface of the beam. This method is known as free layer damping (FLD) treatment. In last configuration, the butyl rubber layer was connected to the steel beam. Using the Unholtz-Dickie UDCO-TA250 electrodynamic vibration system, the natural frequencies and amplitudes of free vibrations for all examined specimens were obtained. The vibration amplitude of the beam was measured using piezoelectric acceleration sensors. In order to define the damping capabilities of both the bitumen based material and the butyl rubber, the relative amplitude of specimens and the loss factor using half-power bandwidth method were calculated.

The damping capabilities of viscoelastic materials depend heavily on the operating temperature. Since these materials are used for passive vibration damping, it is necessary to determine the damping properties of selected materials across a range of temperatures. This paper presents the results of an experimental investigation into the effect of temperature on the damping performance of viscoelastic materials applied to aluminium cantilever beams using free-layer damping (FLD) and constrained-layer damping (CLD) techniques. Butyl rubber and bituminous materials were experimentally tested by modal analysis over a temperature range from 22 °C to −2 °C. Frequency response functions, resonance frequencies, resonance amplitudes, and modal loss factors were determined for selected bending modes. The results show that CLD provides better damping at room temperature, particularly for butyl rubber, due to enhanced shear deformation in the viscoelastic layer. However, as the temperature decreases, material stiffening alters the damping efficiency, and FLD becomes more competitive or superior in several modes. The findings confirm that passive damping effectiveness is strongly dependent on temperature, material type, and vibration mode.