In this paper we review the state of the art in an emerging new technology: embedded ultrasonic non-destructive evaluation (NDE). Embedded ultrasonic NDE permits active structural health monitoring, i.e. the on-demand interrogation of the structure to determine its current state of structural health. The enabling element of embedded ultrasonic NDE is the piezoelectric wafer active sensor (PWAS)...

When a shear ultrasonic wave is incident on a solid and liquid boundary, the proportion that is reflected depends on the liquid viscosity. This is the basis for some instruments for on-line measurement of bulk liquid viscosity. In machine elements, the lubricant is usually present in a thin layer between two rubbing solid surfaces. The thin film has a different response to an ultrasonic shear w...

An experimental study of an influence a strong low-frequency wave on the propagation weak ultrasonic pulses in acoustic resonator made annealed polycrystalline copper has been carried out. The measurements were out with harmonic excitation at its first four longitudinal modes range from 2 to 15 kHz, frequency varied 65 400 kHz. analysis observed nonlinear effects was within framework polycrysta...

Dynamic mechanical analysis (DMA) and ultrasonic measurements were carried out to study the temperature and frequency dependences of viscoelastic properties of polyurea. Master curves of Young’s storage and loss moduli were developed from the DMA data. Relaxation spectra were subsequently calculated by means of two approximate models, and the apparent activation energy of molecular rearrangemen...

Aluminum alloy components typically have structural characteristics such as large size and complex shape, making the in situ non-destructive detection of internal residual stress these structures a challenge that manufacturing sector has tried to solve. Ultrasonic longitudinal critically refracted (LCR) waves shown good sensitivity normal horizontal direction could be used detect distribution c...

This paper deals with an experimental description of the acoustic behaviour of non-consolidated granular materials submitted to static force. The aim of this work is to investigate the effect of a small amount of an interstitial fluid on the acoustic propagation. Measurements of the velocity and of the transmission of the coherent wave are performed for different values of the applied force. It...

In continuous wave ultrasonic Doppler tomography (DT), the ultrasonic beam moves relative to the scanned object to acquire Doppler-shifted frequency spectra which correspond to cross-range projections of the scattering and reflecting structures within the object. The relative motion can be circular or linear. These data are then backprojected to reconstruct the two-dimensional image of the obje...

Ultrasonic measurements of acoustoelastic constants, which relate wave speed changes to applied loads, are one of the few methods for experimentally determining third order elastic constants (TOECs). A typical set of measurements consists of multiple experimental setups using both longitudinal and shear transducers with directions of propagation both parallel and perpendicular to the direction ...

The advent of dry point transducers has allowed new possibilities for ultrasonic testing of concrete structures and rock specimens. Recent developments in the technology such as single and multi-channel ultrasonic pulse echo technology and the automated determination of the modulus of elasticity have been pushing back the boundaries of the method. The effect of this has been to increase the eas...