V.T.Grinchenko, V.N.Oliynik
Harmonic vibration of visco-elastic layer of a biotissue loaded by a smooth round piston

Acoustic bulletin, Vol. 7 4, (2004) p.34-47
A linear problem on harmonic vibrations of viscoelastic layer of material modeling the biotissue loaded with a smooth plane round piston is solved using the boundary integral equations. An efficient algorithm is developed for determining the physico-mechanical fields and impedance of the surface contacting with the piston. It is found that the system demonstrates the resonant behavior in the considered frequency range, and the resonant frequency strongly depends on the piston diameter. With allowance for dissipation in the material and wave radiation mechanism an active component of the contact surface impedance is formed, that is of the same order with its reactive component. The calculated frequency dependencies of the impedance are in good agreement with the experimental data. It is determined that, when passing through the resonance, the mechanic stress distribution is essentially reshaped. Studying of spatial distribution of the layer material displacements has shown that the near-surface area under the piston is excited most intensively. In so doing, the vertical displacements induced by the piston are effectively transformed into the horizontal ones. With the increase of frequency the deformations become more localized in the vicinity of the piston surface. A comparison of the obtained results with known experimental data shows that the used model adequately reflects the main features characteristic of the interaction between human skin and the contact vibrator or sensor.
KEY WORDS:
a linear problem on harmonic vibrations of viscoelastic layer loaded with a smooth plane round piston, biotissue, physico-mechanical fields, impedance of the contact surface
TEXT LANGUAGE: Ukrainian