scholarly journals EXPERIMENTAL ANALYSIS OF DAMPING PROPERTIES OF VISCOELASTIC MATERIALS

2021 ◽  
Vol 27 (2) ◽  
pp. 63-67
Author(s):  
Piotr Łabuński ◽  
Lucjan Witek
Keyword(s):  
Free Vibrations ◽  
Butyl Rubber ◽  
Experimental Investigations ◽  
Steel Beam ◽  
Damping Properties ◽  
Viscoelastic Materials ◽  
Rubber Layer ◽  
Acceleration Sensors ◽  
Materials Used ◽  
Half Power

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.

scholarly journals Моделирование демпферов из вязкоупругих материалов

2021 ◽  
Vol 91 (3) ◽  
pp. 388
Author(s):  
Ю.В. Максимов ◽  
Ю.С. Легович ◽  
Д.Ю. Максимов
Keyword(s):  
Forced Vibrations ◽  
Frequency Characteristics ◽  
Point Of View ◽  
Damping Properties ◽  
Viscoelastic Materials ◽  
Linear Region ◽  
Elastic Deformations ◽  
Materials Used ◽  
Dynamics Problems ◽  
Correct Data

The consideration of damping in structural dynamics problems is an important and non-trivial problem. Its complexity, not least, is due to the need to set the correct data for the materials used and to select a model suitable for analysis. In this paper, we consider some models of viscoelastic materials from the point of view of the possibilities of using these models for the harmonic analysis of the damping properties of various materials in the linear region of elastic deformations. The proposed analysis is based on the use of parameters of viscoelastic materials specified in the form of coefficients of the differential equation of small forced vibrations. It is shown that the considered models are characterized by a different frequency dependence of the parameters of the simulated materials. This opens up the possibility of combining the model with the frequency characteristics of its parameters, approaching the frequency characteristics of the parameters of the studied viscoelastic materials.

scholarly journals THE INFLUENCE OF SEVERAL TYPES OF RESINS ON THE DYNAMIC MECHANICAL PROPERTIES OF POLYMER MIXTURE BASED ON BUTYL RUBBER

2020 ◽  
Vol 3 (2) ◽  
pp. 36-45 ◽  
Author(s):  
O. Tarasova ◽  
Yu. Yurkin ◽  
A. Toroschin
Keyword(s):  
Phenol Formaldehyde ◽  
Dynamic Properties ◽  
Dynamic Mechanical Properties ◽  
Mechanical Analysis ◽  
Strength Properties ◽  
Butyl Rubber ◽  
Polymer Materials ◽  
Polymer Mixture ◽  
Damping Properties ◽  
Dynamic Mechanical

this work is devoted to the problem of developing vibration-damping polymer materials with high damping properties in a wide temperature range. The study of the effect of modifying additives on the strength, damping, adhesive and cohesive properties of a butyl rubber composite is the aim of this work. The task is to identify the actual temperature, frequency, dynamic and mechanical characteristics of a composite material based on butyl rubber depending on the type and concentration of resins. The key methods for studying this problem is the dynamic mechanical analysis method, aimed at obtaining information about changes in the dynamic properties of polymer materials (bond strength with metal when peeling samples of composites, determining the flow resistance of samples, determining the migration of plasticizer). Due to the established experimental dependences, it was found that the addition of resins (3% by weight) in the composition based on butyl rubber leads to an increase in the damping properties of composite materials, and an increase to (4.25% by weight) leads to their decrease. It was established that the obtained filled mixtures with a high damping peak and good adhesive and strength properties are mixtures with the addition of alkyl phenol-formaldehyde resins.

Specification of Destructive Influences of Selected Decontamination Mixtures on Materials Used for Construction of Chemical Specialists´ Garments Designated for Isolative Protection of the Body Surface

2018 ◽  
Vol 24 (3) ◽  
pp. 138-145
Author(s):  
Zdeněk Melichařík ◽  
Pavel Otřísal
Keyword(s):  
Body Surface ◽  
Armed Forces ◽  
Selective Decontamination ◽  
Butyl Rubber ◽  
The Body ◽  
Effective Protection ◽  
Materials Used ◽  
Protective Garment ◽  
Repeated Contact

Abstract A paper deals with the influence of selective decontamination mixtures established in the Czech Armed Forces on an isolative protective foil used to the construction of anti-gas protective garment marked as OPCH-05. Presented information are a part of thematically focused works aimed to study of influences of all established decontamination mixtures on the Czech Armed Forces Chemical Corps´ garments of anti-gas protection. The quality of provided the Czech Armed Forces Chemical Corps´ specialists isolative protection is limited with the existence of several aspects which significantly determine with their materials equipment. For providing isolative protection of the body surface are used such as protective garments which are the hermetic type and they are constructively solved with the employment of the butyl-rubber polymeric mixture. The effective protection of the body surface must be guaranteed even within the presumption of a repeated contact with decontamination mixtures

scholarly journals A Study on Organic Modification of Damping Properties of Polyurethane Materials for Building

2018 ◽  
Vol 175 ◽  
pp. 01017
Author(s):  
Feng Zhou ◽  
Jianjun Gan ◽  
Xin Du ◽  
Ligang Cui
Keyword(s):  
Silicone Oil ◽  
Poor Performance ◽  
Load Test ◽  
Inorganic Filler ◽  
Test Machine ◽  
Polyurethane Elastomer ◽  
Damping Properties ◽  
Viscoelastic Materials ◽  
Viscoelastic Dampers ◽  
Dynamic Load Test

The damping property of viscoelastic dampers is mainly based on the shear hysteretic behaviorof viscoelastic materials, so as to reduce the dynamic response of viscoelastic materials. Therefore, theviscoelastic damping properties of viscoelastic materials greatly affect the viscoelastic dampers. At present, viscoelastic materials mainly use rubber materials, but in this thesis, the excellent properties of polyurethaneelastomer materials are used to replace rubber materials and applied to viscoelastic dampers. However, purepolyurethane elastomer damping properties are related to poor performance, so it should be modified. Basedon the research of inorganic filler-modified polyurethane elastomer, the research group modified the threekinds of organic chemicals with hydroxyl silicone oil, HTPB liquid rubber and epoxy resin E-51, in the lowfrequency region of 0.025Hz-1.5Hz through the dynamic load test machine to test the dampingperformance.

A Theoretical and Experimental Study of Vibrations of Thick Circular Cylindrical Shells and Rings

1988 ◽  
Vol 110 (4) ◽  
pp. 533-537 ◽  
Author(s):  
R. K. Singal ◽  
K. Williams
Keyword(s):  
Cylindrical Shells ◽  
Three Dimensional ◽  
Free Vibrations ◽  
Theory Of Elasticity ◽  
Frequency Equation ◽  
Experimental Investigations ◽  
Resonant Frequencies ◽  
Modes Of Vibration ◽  
Circular Cylindrical Shells ◽  
Experimental Values

The free vibrations of thick circular cylindrical shells and rings are discussed in this paper. The well-known energy method, which is based on the three-dimensional theory of elasticity, is used in the derivation of the frequency equation of the shell. The frequency equation yields resonant frequencies for all the circumferential modes of vibration, including the breathing and beam-type modes. Experimental investigations were carried out on several models in order to assess the validity of the analysis. This paper first describes briefly the method of analysis. In the end, the calculated frequencies are compared with the experimental values. A very close agreement between the theoretical and experimental values of the resonant frequencies for all the models was obtained and this validates the method of analysis.

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