Related Experiment Video
Updated: Aug 4, 2025

Studying Large Amplitude Oscillatory Shear Response of Soft Materials
Published on: April 25, 2019
Longitudinal motion of focused shear wave beams in soft elastic media
Branch T Archer1, Yu-Hsuan Chao2, John M Cormack3
1Chandra Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712, USA.
Abstract:
Shear waves are employed in medical ultrasound imaging because they reveal variations in viscoelastic properties of soft tissue. Frequencies below 1 kHz are required due to the substantially higher attenuation and lower propagation speeds than for compressional waves. Shear waves exhibiting particle motion in the direction of propagation, referred to as longitudinal shear waves, can be generated with longitudinal motion of a circular disk on the surface of a soft elastic medium. This approach permits imaging of the longitudinal shear wave with a conventional ultrasound transducer that is coaxial with the source of the shear wave. Presented here is a mathematical model describing the complete wave field generated by displacement at the surface of an isotropic elastic half-space. Numerical simulations are shown for longitudinal, transverse, torsional, and radial source polarizations, with emphasis on focused longitudinal shear waves. Predictions are consistent with measurements of light beams revealing that the longitudinal electric field component produces a smaller focal spot than the transverse field component [Dorn, Quabis, and Leuchs, Phys. Rev. Lett. 91, 233901 (2003)]. Simulations are compared with preliminary measurements of a focused longitudinal shear wave beam generated in a soft tissue phantom by longitudinal motion of a spherically concave piston.
More Related Videos
04:51Author Spotlight: Characterizing Environmental Biofilm Mechanics Using Optical Coherence Elastography and its Applications in Wastewater Treatment
Published on: March 1, 2024
07:19Preparation of Extracellular Matrix Protein Fibers for Brillouin Spectroscopy
Published on: September 15, 2016
Related Concept Videos
Elastic Strain Energy for Shearing Stresses
Shearing Stresses in a Beam: Problem Solving
Elastic Curve from the Load Distribution
For all beams, the analysis of the beam's reaction to distributed loads begins by understanding the relationship between a beam's load and the resulting shear forces and bending moments.
Travelling Waves
Water waves, sound waves, and seismic waves are some examples of mechanical waves. For water waves, the wave propagation medium is...
Shear on the Horizontal Face of a Beam Element
Distribution of Stresses in a Narrow Rectangular Beam