An Investigation into the ASTM E756-05 Test Standard Accuracy on Determining the Damping Properties of Materials in Tens
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CTURAL MECHANICS AND STRENGTH OF FLIGHT VEHICLES
An Investigation into the ASTM E756-05 Test Standard Accuracy on Determining the Damping Properties of Materials in Tension-Compression V. N. Paimushina, b, V. A. Firsova, *, V. M. Shishkinc , V. A. Kostina, and R. Sh. Gimadievd a
Tupolev Kazan National Research Technical University, ul. Karla Marksa 10, Kazan, 420111 Tatarstan, Russia b Kazan (Volga region) Federal University, ul. Kremlevskaya 18, Kazan, 420008 Tatarstan, Russia c Vyatka State University, ul. Moskovskya 36, Kirov, 610000 Russia d Kazan State Power Engineering University, ul. Krasnosel’skaya 51, Kazan, 420066 Tatarstan, Russia *e-mail: [email protected] Received May 21, 2019; revised June 5, 2019; accepted December 18, 2019
Abstract—The features of identifying the damping properties of viscoelastic materials caused by their dependence on a large number of external factors are discussed. The main propositions of the international standard on the experimental method for determining the damping properties of viscoelastic materials under cyclic tension–compression are analyzed. A refined finite element model of the dynamic behavior of the Oberst beam with a damping layer of a viscoelastic material with accounting of the transverse shear and compression is constructed. A numerical analysis of the error in determining the damping properties of a viscoelastic material under tension–compression caused by the neglect of transverse shear and compression strains arising in the layer of the material being tested is carried out. DOI: 10.3103/S106879982002004X Keywords: viscoelastic material, damping properties, frequency of oscillations, Oberst beam, finite element model, transverse shear and compression.
INTRODUCTION Vibration damping via viscoelastic materials is a widely used and technologically simple method for solving the problems of sound and vibration protection of structural elements in aircraft, automotive, shipbuilding, and other industries. Achieving the desired results in the absorption of harmful vibrational energy is possible in various ways. However, it is very problematic to do with a minimal increase in the mass of the structure, which is especially important for the aerospace industry. Therefore, it is an urgent task. The effectiveness of any damping material is determined by the product of its elastic modulus E by the loss coefficient η [1]. Moreover, the latter values can vary in different directions. Instead of the coefficient η, one can use the logarithmic decrement of vibrations δ = ηπ. Elastomers based on rubber or thermoplastics based on bitumen with various fillers are often used as damping materials. To increase the viscoelastic properties in the operating temperature range, fillers, fibers, limestone, clay, tackifier, etc. are used as fillers [2–4]. The determination of the damping properties of viscoelastic materials is associated with significant difficulties. This is primarily due to the fact that damping properties are functions of a significant number of factors, namely, temp
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