and N. S. Kosenko bA method is proposed for the determination of the amplitude dependence of the true vibration decrement of homogeneous materials deposited as coatings on a substrate of rectangular cross section. The method is based on the self-consistent calculation of energy loss factors for the substrate and coating materials using experimental amplitude dependences of vibration decrement for coated substrate, obtained under the conditions of cantilever specimens of rectangular cross section. The applicability of the method is illustrated by the determination of values of the true vibration decrement of Co-20 wt.% Fe alloy deposited as a coating on VT1-0 titanium alloy.Notation δ c -vibration decrement of the substrate-coating system δ 1 , δ 2 -true vibration decrements of the substrate and coating materials A j -vibration amplitude of the free end of a cantilever specimen ε ij -mean strain on the surface of the ith portion at the vibration amplitude A j of the free end of specimen ε j -strain amplitude on the specimen surface in the case of pure-bending vibration ε -strain amplitude in the case of pure-bending vibration E 1 , E 2 -elastic moduli of the substrate and coating materials V 1 , V 2 -volumes of the substrate and coating materials V i 1 , V i 2 -volumes of fragments of the ith portion of the substrate and coating h 1 , h 2 -thicknesses of the substrate and coating S i -area of the ith portion of the substrate K -coefficient depending on the shape of the substrate I L i x ( ) − Δ -mean moment of inertia of the cross section of the ith portion of specimen L -specimen length N -number of points on the experimentally measured plot of vibration decrement against amplitude 0039-2316/07/3906-0663Introduction. The use of damping coatings for various machine and mechanism elements which are subjected to intensive dynamic loads makes it possible to greatly reduce the vibration and noise level in them [1,2]. The development of a material for damping coatings involves a need for the estimation of the efficiency of vibrational energy dissipation by them in real articles. It is usually performed on the basis of experimental data by comparing the characteristics of the damping capacity of composite specimens, which are coatings deposited on substrates of the same shape and composition [1].If the damping characteristics of both materials of the composite are known, the effectiveness of the use of coatings can be assessed theoretically by calculating the vibration decrement for the substrate-coating system [1, 2]. At the same time, such characteristics are generally obtained on massive specimens [3,4], their values depending on the structure of the material [5]. Since the structure of coatings depends largely on the technology and conditions of their deposition, the prediction of dissipative properties of the composite system from the data obtained on massive specimens with the structure that is uncharacteristic of the coating, may lead to a great error. Taking into account the above, it seems expedient to solve an...

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and N. S. Kosenko bThe dependence of dissipative properties of copper condensates on the grain size has been studied. Condensates with a grain size of 0.9-3.7 μm were obtained by electron-beam vapor deposition of copper as coatings on a titanium substrate. The oscillograms of damped bending vibrations of the substrate-coating system were recorded at a frequency of 140-150 Hz in the temperature range 20-350°C. The values of true logarithmic vibration decrement for copper condensates were determined by the self-consistent calculation of energy loss factors of the substrate and coating by the method proposed in the part 1. It has been shown that the amplitude dependences of the true logarithmic vibration decrement of copper condensates at room and elevated temperature are largely determined by their structure.

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