https://purehost.bath.ac.uk/ws/files/127136834/Paper_Journal_of_sound_and_vibrations_reviewed.pdf

Nonlinear ultrasound modelling and validation of fatigue damage

In this Letter, the time reversal mirror is used to focus elastic energy at a prescribed location and to analyze the amplitude dependence of the focus signal, thus providing the nonlinearity of the medium. By varying the frequency content of the focused waveforms, the technique can be used to probe the surface, by penetrating to a depth defined by the wavelength of the focused waves. The validity of this concept is shown in the presence of gradual and distributed damage in concrete by comparing actual results with a reference nonlinear measurement and X ray tomography images.

/pdf/probing-material-nonlinearity-at-various-depths-by-time-2bobzpgq26.pdf

Probing material nonlinearity at various depths by time reversal mirrors

Micromechanical modelling of dry and saturated cement paste: Porosity assessment using ultrasonic waves

Simulation study of a chaotic cavity transducer based virtual phased array used for focusing in the bulk of a solid material

Depth profile of a time-reversal focus in an elastic solid

Dual energy time reversed elastic wave propagation and nonlinear signal processing for localisation and depth-profiling of near-surface defects: a simulation study.

Els Janssen

Papers

Dual energy time reversed elastic wave propagation and nonlinear signal processing for localisation and depth-profiling of near-surface defects: a simulation study.

Exploiting time reversal principles for the accurate determination of material velocities

Exploiting time reversal principles for the accurate determination of longitudinal and shear material velocities

Imaging multiple defects in solids by means of selective source reduction and time reversed acoustics