To the Construction of the Amplitude Dependence of Internal Friction with Vibrations of Porous Metal Composites

Abstract

Purpose of research was to plot the amplitude dependence of the decrement of longitudinal and bending vibrations of samples of porous metal composites manufactured using 3D technology.Methods. The main attention is paid to the role of microplasticity in the scattering of the vibration energy, since the decrement value in composite will be greater than in monolithic material. The effect of porosity on the level of energy dissipation is taken into account. We have used a statistical model based on the results of the theory of functionals given on random processes.Results. This made it possible to find the concentration of microplastic zones in the composite during longitudinal and bending vibrations of the sample. The value of the vibration decrement is defined as the ratio of the potential energy of plastic deformations to the total potential energy of the entire sample. To calculate the effective moduli in the composite, the well-known technique of the theory of elasticity of micro-inhomogeneous media is used. The results obtained indicate that porosity significantly affects the concentration of microplastic zones and the scattering of internal friction during longitudinal and bending vibrations. However, it should be noted that at low amplitudes, microplastic regions are not formed in the vicinity of the pores. Therefore, the reasons for the appearance of energy dissipation are not explained only by microplasticity. The source of such losses are dislocation, ferromagnetic and other reasons. However, the level of these losses is much less than that indicated in this work, and depends only on the oscillation frequency.Conclusion. The results obtained can be used to establish the patterns of behavior of various natures of ingot, powder and composite materials with high dispersion in phase and structural components in various conditions and states.