Józef Kubik

Short ultrasonic waves in cancellous bone

A new cellular model of the propagation of short ultrasonic waves in cancellous bone is introduced. The theoretical results derived from the proposed model have been compared with the well known macrocontinual Biots theory. Independently, the experimental results obtained by the pulse transmission method for cancellous bovine bone and a model material have been reported. The data from time and frequency domain are analyzed and discussed in light of the two-phase description developed under long and short wave assumption.

Multiphase nature and structure of biomaterials studied by ultrasounds

The paper discusses the applicability of a two-phase model of saturated porous materials for a description of the results of broadband ultrasonic studies of wave parameters in bovine trabecular bone. The analysis is focused on the role of the internal structure of the materials in the propagation of dilatational waves within the frequency range with a significant attenuation of wave energy due to absorption and scattering. The applicability of ultrasonic studies for the determination of characteristic macro- and micro-structural parameters of biomaterials using a model-based approach is considered.

Scattering of ultrasonic waves in randomly layered materials

The goal of the paper is the proposal of a new macroscopic description of scattering of elastic waves at internal inhomogeneities of the material. Within the studies the microscopic inhomogeneity of the medium is modeled as the alternately arranged two kinds of elastic layers of random thicknesses and different mechanical properties. Calculations of the acoustical characteristics of such medium (reflection and transmission coefficients) are performed in two stages: (i) first the problem of interaction of plane harmonic wave with the half space of the randomly layered medium for the case of normal wave incidence is analyzed; (ii) then the interaction of the harmonic wave with the slice composed of randomly layered structure is considered. Such approach allowed to derive analytical relations for the phase velocity of wave propagation and attenuation as the explicit functions of frequency, stochastic structural parameters of the medium and material properties of layers. The obtained formulas are helpful for ...

Studies of Rayleigh Scattering of Longitudinal Waves in Saturated Porous Materials

The paper presents experimental results and a model for propagation of ultrasonic waves in fluid saturated porous material. The model aimes at development of a two-phase description of the media assuming the presence of pore and solid scattering represented by complex and frequency dependent elastic moduli. A simple procedure allowing for determination of scattering parameters is proposed and comparison of model prediction and experimenatl data for attenuation of longitudinal waves is performed.