The paper presents the Lamb wave attenuation of Carbon Fiber Reinforced Plastic (CFRP) plates on the basis of an experimental transmitter-sensor scheme. We measured separately the S0 and A0 Lamb modes of CFRP plates with three different kind of laminate lay-ups; unidirectional [0]8s (and [90]8s), cross-ply [0, 90]4s, and quasi-isotropic [0,45,-45,90]2s. Several ultrasound transmitters were used...

During the propagation of ultrasonic waves in structures, there is usually energy loss due to ultrasound energy diffusion and dissipation. The aim of this research is to characterize the ultrasound energy diffusion that occurs due to small-size damage on an aluminum plate using piezoceramic transducers, for the future purpose of developing a damage detection algorithm. The ultrasonic energy dif...

Theory of Lamb Wave propagation in plate-like structures have found many practical applications in Structural Health Monitoring. However for better understanding of complex physical phenomena associated with wave propagation and wave interaction with damage numerical simulations are as important as laboratory experiments. The paper shows the application of Cellular Automata technique for modeli...

Currently, bone mineral density (BMD) is the gold standard for in vivo assessment of frac23 ture risk of bones and is measured using X-ray absorptiometric techniques.1 However, only 24 70–80% of the variance of bone strength is accounted for by bone density. As the brittle25 ness of bone depends on more factors than bone density, biologists believe that quantitative 26 ultrasound techniques (QU...

The study of nonlinear elastic wave propagation has been of considerable interest for the last four decades. This, in part, is due to the fact that nonlinear parameters are, in general, more sensitive to structural defects than linear parameters. Although guided waves combine the sensitivity of nonlinear parameters with large inspection ranges there are very few studies of guided nonlinear elas...

The nondestructive evaluation (NDE) of adhesively bonded structures is a complex process. Earlier work has confirmed that ultrasonic waves are influenced by the properties of the material in which they travel. Acousto-ultrasonic methods have been widely used by previous researchers to generate ultrasonic waves in plates and bonded structures for flaw detection, visualization, and measurements o...

It is known that the biological activity of the brain involves radiation of electric waves. These waves result from ionic currents and charges traveling among the brain’s neurons. But it is obvious that these ions and charges are carried by their relevant masses which should give rise, according to the gravitational theory, to extremely weak gravitational waves. We use in the following the stoc...

A damage detection technique, which does not rely on any past baseline signals, is proposed to assess damage in composite plates by using an enhanced time reversal method. A time reversal concept of modern acoustics has been adapted to guided-wave propagation to improve the delectability of local defects in composite structures. In particular, wavelet-based signal processing techniques have bee...