Radiative transfer and multiple scattering of diffuse ultrasound" (1994). Faculty Publications from the Department of Engineering Mechanics. Paper 6. A model is presented for the mtltiply scattered incoherent field in a continuous polycrystalline elastic medium. Unlike a previous, development based upon energy conservation considerations [J.] for a medium containing discrete random scatterers, ...

A simple method for imaging ultrasonic fields in clear media is introduced. A modulated laser source is used to project the ultrasonic field onto a CCD camera. By use of the source-synchronized lock-in detection scheme, 2D images of the amplitude and phase distributions can be determined simultaneously. This technique is experimentally demonstrated with a 1-MHz and a 3.5-MHz ultrasonic transduc...

In this paper we demonstrate an optically powered ultrasonic t ransducer. It has a high efficiency and was designed and fabricated using MEMS (microelectromechanical system) techniques. It can generate narrowband ultrasound from broadband laser excitation. It is a simple two-mask-level MEMS device with a micro-disc seated on a micro-stem. As a laser pulse is incident on the disc centre, the dis...

In this article, embedded ultrasonic sensors were prepared using 1–3-type piezoelectric composite and piezoelectric ceramic as the piezoelectric elements, respectively. The frequency bandwidth of the novel embedded ultrasonic sensors was investigated. To obtain the relationship between the receiving ultrasonic velocity and compressive strength, as well as their response signals to crack damage,...

Coda wave interferometry (CWI) has been used to measure the relative wave-velocity change (dV/V) caused by small changes in materials. This study uses stretching processing technique which for CWI analysis investigate velocity of direct longitudinal (P) wave, shear (S) and coda concrete choosing different time windows ultrasonic signals. It is found that obtained depends on window position, bec...

Electromagnetic ultrasonic transducer is the core component of the electromagnetic ultrasonic testing equipment. This paper establishes a three-dimensional model of the electromagnetic ultrasonic transducer used to generate Lamb wave, then by uniform design experiment and finite element analysis, the paper obtains the law between the eddy current density, the conductor width, length of the coil...

The problem of propagation of plane wave including body and surface waves propagating in a transversely isotropic half-space with a depth-wise axis of material symmetry is investigated in details. Using the advantage of representation of displacement fields in terms of two complete scalar potential functions, the coupled equations of motion are uncoupled and reduced to two independent equations...

A novel microcomputer-based ultrasonic distance measurement system is presented. This study proposes an efficient algorithm which combines both the amplitude modulation (AM) and the phase modulation (PM) of the pulse-echo technique. The proposed system can reduce error caused by inertia delay and amplitude attenuation effect when using the AM and PM envelope square wave form (APESW). The APESW ...

Introduction: Improving the capability of nondestructive evaluations requires the analysis of suitable models dealing with the physical and mechanical phenomena involved in the experiments. For example, ultrasonic tests may be a powerful, fast and effective method for nondestructive characterization of mechanical properties of materials. This requires the study of the related elastodynamic prob...