Nonlinear Viscoelastic Wave Propagation: An Extension of Nearly Constant Attenuation Models

Constant Q-Wave Propagation and Attenuation

A linear model for attenuation of waves is presented, with Q, or the portion of energy lost during each cycle or wavelength, exactly independent of frequency. The wave propagation is completely specified by two parameters, e.g., Q and Co, a phase velocity at an arbitrary reference frequency w0. A simple exact derivation leads to an expression for the phase velocity c as a function of frequency:...

Rheological Response and Validity of Viscoelastic Model Through Propagation of Harmonic Wave in Non-Homogeneous Viscoelastic Rods

This study is concerned to check the validity and applicability of a five parameter viscoelastic model for harmonic wave propagating in the non-homogeneous viscoelastic rods of varying density. The constitutive relation for five parameter model is first developed and validity of these relations is checked. The non-homogeneous viscoelastic rods are assumed to be initially unstressed and at rest....

Identification of Viscoelastic Materials by Use of Wave Propagation Methods

Pressure Wave Propagation in Liquid-Filled Tubes of Viscoelastic Material

The propagation of small-amplitude waves in a thick-walled long viscoelastic tube of variable cross-section, filled with a viscous incompressible fluid, is considered with account for wave reflection at the tube end in application to arterial pulse wave propagation. A solution is obtained in the form of expansions in a small parameter. The effect of the coefficient of wave reflection at the tub...

Detection of Cardiac Occlusions Using Viscoelastic Wave Propagation

We consider the problem of detecting cardiac artery occlusions using stenosis driven viscoelastic (VE) waves propagated through biotissue to body surface sensors. We investigate possible statistical model formulations (ordinary least squares (OLS), generalized least squares (GLS)) and post analysis techniques (residual plots) to ascertain uncertainty in estimates as well as validity of the stat...