Introduction to Ultrasonic Waves

This review article is focused on the analysis of the state of the art of sensors for guided ultrasonic waves for the detection and localization of impacts, therefore of interest for the structural health monitoring (SHM).

In structural health monitoring (SHM) applications, fiber Bragg grating (FBG) sensors are typically bonded directly to the surface of a structure to detect ultrasonic waves for damage identification.

5) to structure-guided ultrasonic waves up to 450 kHz – the first time that piezoresistive sensors implanted in CFRPs respond to dynamic strains in such a broad frequency band.

This review article is focused on the analysis of the state of the art of sensors for guided ultrasonic waves for the detection and localization of impacts, therefore of interest for the structural health monitoring (SHM).

In this work, we study the influence of the local porosity in isotropic reactive cast particulate reinforced metal–matrix composites on the statistical amplitude distribution of backscattered broadband pulses of longitudinal ultrasonic waves.

A direct method is used to measure the real damage of the steel and to determine its physical properties, namely, the velocity and the attenuation coefficient of longitudinal ultrasonic waves, the coercive force, the eddy current parameter, and the self-magnetic field, at various stages of static and cyclic loading.

Conventional PPM EMATs generate ultrasonic waves, which simultaneously propagate both forward and backward.

This magnetic field distribution enables Halbach EMATs to generate ultrasonic waves with relatively large amplitude.

The decomposition of gaseous toluene as a representative volatile organic compound using 200 kHz ultrasonic waves was investigated as a new air cleaning method that does not require an ultraviolet light source, in accordance with the Minamata Convention on Mercury.

The cellulose obtained will be hydrolyzed using 5% HCl and 5% H2SO4 under the effect of 20 kHz ultrasonic waves for 90 minutes.

The ultrasonic sensors are placed in the front portion of the vehicle which is set to propagate and receive ultrasonic waves while moving.

The ability of the device to emit and receive ultrasonic waves increases with the bias voltage but does not depend on the voltage polarity.

When the absorber is irradiated by a Gaussian pulsed laser, due to the extremely short time, the absorber can be regarded as adiabatic expansion after absorbing energy, thereby generating ultrasonic waves.

When the absorber is irradiated by Gaussian pulses, due to the extremely short time, the absorber can be regarded as adiabatic expansion after absorbing energy, thereby generating ultrasonic waves.

In structural health monitoring (SHM) applications, fiber Bragg grating (FBG) sensors are typically bonded directly to the surface of a structure to detect ultrasonic waves for damage identification.

We present a new noncontact methodology to excite and detect ultrasonic waves in rocks under in situ pressure and temperature conditions.

In order to determine the optimal parameters when using an ultrasonic probe to measure cavern geometry when a metal borehole pipe is present, an investigation was firstly carried out on influence of a vertical metal plates with a thickness from 1 mm to 15 mm immersed in water on transmitted and reflected ultrasonic waves.

In recent studies, geophysical precursors were identified as distinct maxima and minima in the amplitude of transmitted and reflected ultrasonic waves propagating through synthetic rock joints prior to the shear failure.

Ultrasonic particle manipulation (UPM), a non-contact and label-free method that uses ultrasonic waves to manipulate micro- or nano-scale particles, has recently gained significant attention in the microfluidics community.

This paper proposed a method that uses ultrasonic waves to improve the seepage characteristics of CBM reservoir and theoretically verifies the feasibility of this idea using numerical simulation.

The diffuse ultrasonic waves were considered to evaluate the health status of the tested structures.

Based upon the continued endeavors of the authors in developing SHM approaches and exploring real world applications, an in-situ SHM approach, exploiting active diffuse ultrasonic waves (DUW) and a benchmark-less method, has been developed and implemented in a marshalling station in China.

These two phononic crystals have opposite rotation angles possessing different topological properties, and the relative position of them leads to a forbidden band for the underwater ultrasonic waves.

We propose a method using underwater ultrasonic waves.

The present paper is concerned with the study of nonlinear ultrasonic waves in a magneto thermo (MT) elastic armchair single-walled carbon nanotube (ASWCNT) resting on polymer matrix.

Further investigations on the effects of surface roughness on nonlinear ultrasonic waves are also being carried out.

PA technology for NDT/E includes the use of a modulated continuous-wave laser and a pulsed laser for PA wave excitation, PA-generated ultrasonic waves, and all-optical PA wave excitation and detection.

The experimentally validated numerical model that simulates the interaction of laser-generated ultrasonic waves with subsurface defects is first established, which is further utilized to generate adequate laser ultrasonic signals for training the CNN model.

This method utilizes ultrasonic waves to scan the surface of a submerged object in a watercoupled medium.

In this work, an alternative method that utilizes ultrasonic waves to relay information at high data rates is introduced.

The problem of detecting adhesions (areas of a weld seam with lack of penetration that conduct ultrasonic waves well but do not provide mechanical strength) is solved.

The problem of adhesion detection was successfully solved (weld zones with incomplete fusion conduct ultrasonic waves well, but do not provide mechanical strength).

This research focuses on the performance augmentation of a coil and shell heat exchanger using high frequency ultrasonic waves by the commercial computational fluid dynamics program FLUENT.

1MHz frequency ultrasonic waves are emitted by a transmitter and received by a receiver opposite each other with a distance of 9.

25 MHz, ultrasonic transducer transmitted ultrasonic waves through the tool plate and into the composite part and measured the amplitude and time of flight of the reflected waves with a 1 mm × 1 mm step size/areal resolution.

Point-contact transducers transmitted ultrasonic waves into ice core samples from a temperate glacier.

The MWCNTs are then dispersed into the nanoparticles by high-power ultrasonic waves to fabricate nanocomposite structures.

Under high-power ultrasonic waves, the PTFE powder was dispersed into nano-to sub-micrometer-sized particles and then encapsulated the Al microparticles to form the core-shell structure.

The problem of detecting adhesions (areas of a weld seam with lack of penetration that conduct ultrasonic waves well but do not provide mechanical strength) is solved.

The problem of adhesion detection was successfully solved (weld zones with incomplete fusion conduct ultrasonic waves well, but do not provide mechanical strength).

In recent studies, geophysical precursors were identified as distinct maxima and minima in the amplitude of transmitted and reflected ultrasonic waves propagating through synthetic rock joints prior to the shear failure.

However, ultrasonic waves propagating inside solid bodies are affected by temperature, roughness, differences in microstructure, defects, and others.

Tactile feedback in the room via ultrasonic waves could provide a remedy here.

The application of ultrasonic waves could reduce the rebound rate of aluminum alloy component.

This paper showcases a quantitative investigation of scattering of ultrasonic waves experiences when impinging on a cylindrical defect inside a solid cylinder.

Particles or cells in suspension and exposed to ultrasonic waves experience an acoustic radiation force ( F R ) which, under certain conditions, drives them toward positions of acoustic equilibrium.

The frequency and accuracy parameters of the AO LMS for traveling ultrasonic waves excited in the AO modulator used as a measure (ruler) are analyzed.

Therefore, this study examined a method for detecting subsurface defects using ultrasonic waves excited by a laser.

Along with such advantages as high resolution over the entire area of reflector image reconstruction and the ability to produce images taking into account the reflection from and transformation of wave type at the boundaries of a test object, reconstruction of reflector images by the digital antenna focusing (DFA) method has several disadvantages, including a large volume of measured echo signals, long image reconstruction time, and an insufficiently high energy of ultrasonic waves introduced into the test object.

Image recovery of reflectors by digital antenna focusing (DFA), along with such advantages as high resolution over the entire image recovery area of reflectors, the ability to obtain images taking into account the reflection and transformation of the wave type from the boundaries of the object of control, has several disadvantages: a large volume of measured echo signals, a long image recovery time and insufficient energy of ultrasonic waves introduced into the object of control.

Based on the velocities of ultrasonic waves propagation, it is possible to calculate the elasticity dynamic modulus, which let assess the tendency of the rock skeleton to compaction as a result of the effective stress action.

A combination of spectral characteristics of repeatedly reflected signals and speed of ultrasonic waves propagation is proposed as informative parameters based on experimental studies.