Results 251 to 260 of about 201,609 (321)
Shear wave dispersion and mechanical relaxation spectra
Journal of Physics D: Applied Physics, 1999 It is shown that a mechanical stress relaxation spectrum may be obtained directly from measurements of the dispersion of shear waves in viscoelastic media. The effectiveness of this spectrum, in terms of its sensitivity and accuracy in parametrizing distributions of stress relaxation in the frequency domain, is demonstrated with reference to several ...
P. R. Williams, S Ravji
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Shear wave dispersion in mechanically self-similar gel networks
Journal of Physics D: Applied Physics, 1998 A study of viscoelastic shear wave dispersion in a simulated gelation process involving mechanically self-similar nodal networks is reported. The network formed at the gel point (the infinite network cluster, or `critical gel') shares a common structural feature of smaller network clusters and the onset of a recognizably `gel-like' feature is shown to ...
P. R. Williams, R. L. Williams
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Tunable Wave Dispersion in 3D Woodpile Mechanical Metamaterials
2014 International Symposium on Optomechatronic Technologies, 2014 We numerically and experimentally investigate the nonlinear wave dispersion in 3D woodpile periodic structures consisting of slender cylindrical rods. The slender rods have low frequency resonance modes that are coupled with the propagating wave. Depending on the coupling of local modes, the propagating waveform in woodpile can change significantly ...
Eunho Kim +3 more
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Journal of Rheology, 1994 A new rheometrical technique has been developed to determine the mechanical relaxation spectra of viscoelastic materials by measurement of shear wave group and phase velocities in a virtual gap rheometer. The technique’s sensitivity and accuracy in providing relaxation spectra directly from measurements arises from exploitation of marked changes in ...
P. R. Williams, David J. Williams
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Measurement of tissue mechanical properties with shear wave dispersion ultrasound vibrometry (SDUV)
2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2009 Shear wave dispersion vibrometry (SDUV) produces motion in tissue using sequential pulses of ultrasound radiation pressure. The resulting motion of the tissue in the form of propagating shear waves can provide information about the material properties of the tissue given the appropriate equations of motion for the geometry of the tissue.
J. F. Greenleaf +2 more
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The Journal of the Acoustical Society of America, 2012 The cardiovascular diseases such as atherosclerosis, coronary artery disease, hypertension and diastolic dysfunction have been associated with arterial stiffening and decreased ventricular compliance. Noninvasive techniques capable of quantifying elasticity and viscosity of cardiovascular tissues could facilitate early diagnosis and improve treatment ...
Ivan Nenadic +4 more
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Journal of Ultrasound in Medicine, 2012 Ultrasound vibrometry can measure the propagation velocity of shear waves in soft tissue noninvasively, and the shear moduli of tissue can be estimated inversely from the velocities at multiple frequencies. It is possible to choose the appropriate model for tissue characterization from mathematical methods and analysis of model behaviors.
Ke Chen +4 more
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International Journal of Solids and StructuresIt is well known from the literature that the phase velocity of waves is directly correlated with the stiffness of the material; however, experimental practice shows that this velocity changes significantly with varying frequencies, despite the fact that the elastic modulus of the material is, by definition, a material constant.
Nicola De Fazio +5 more
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Wave Dispersion Characteristics of Continuous Mechanical Systems
, 2023 Farzad Ebrahimi
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