Ultrasonics

In vivo 3D ultrasound imaging with 2D-array transducers is of great importance for both clinical application and biomedical research, but it is complicated in fabrication and also very expensive in hardware due to thousands of electronic channels. In this work, we demonstrate a new fabrication process of 7-MHz 128 + 128 elements row-column-array (RCA) transducer with relaxor ferroelectric PMN-0.28PT single crystal. With piezoelectric single crystal and improved acoustic matching, the optimized performance of -6 dB bandwidth of ∼82 % and insertion loss of -44...

In the field of structure health monitoring (SHM), the use of Lamb wave to locate damage is a common method. Energy focusing is beneficial for damage localization because of higher SNR and higher resolution. Optimization design of elastic metamaterials is promising for energy focusing based on speed modulation. However, current design scheme is effective only for narrowband Lamb waves. Compared to narrowband waves, broadband Lamb waves with a larger frequency range carry richer structural information. In this study, an energy focusing method based on broadband Lamb waves by simultaneous designing excitation waveforms and elastic metamaterials is proposed...

Conventional water immersion ultrasonic testing faces limitations due to factors such as environmental conditions, workpiece dimensions, corrosion, and resource wastage. Contact-based coupling methods, which employ coupling media or specific coupling structures, offer a convenient approach to coupling acoustic waves and reduce signal attenuation. However, these methods are time-sensitive and lack adaptability to uneven surfaces, particularly when dealing with workpieces featuring subtle undulations, resulting in significant signal decay...

Liquid level detection plays an important role in industry. For the liquid level detection of flammable, explosive and volatile liquids, the detection method based on the ultrasonic principle is usually adopted. Though a lot of efforts, the detection precision is still challenging. Herein, Ultrasonic liquid level detection method is studied to address the detection precision. A projection model of the inner wall of the sound beam is established. The transmitter-receiver probe is placed near the height of the liquid level on the outer wall of the liquid tank...

Ultrasonic techniques have been applied to assess crucial physical parameters in various types of fuels including the speed of sound (SoS), the bulk modulus and the acoustic attenuation coefficient. Such investigations may have important practical significance as the knowledge of fuel properties is directly related to the analysis of combustion characteristics, engine's overall performance and exhaust emission in the environment. Nevertheless, typical pulse-echo acoustic methods, require the exact determination of both acoustic source - reflector distance and the time of flight of a finite temporal width ultrasonic pulse, setting thus an upper limit as regards the accuracy of the measurements...

Piezoelectric semiconductors (PSs) possess the physical properties of piezoelectric and semiconductor simultaneously. When a piezomagnetic (PM) material is added to the PS, the composite structures will exhibit the comprehensive mageto-electro-semiconductive (MES) coupling effects. In this paper, the propagation characteristics of shear horizontal (SH) waves in a multiferroic composite semiconductor structure are investigated, where a n-type PS thin plate is perfectly bonded to a semi-infinite PM substrate...

High frame rate ultrasound (US) imaging techniques in 3D are promising tools for capturing abdominal aortic aneurysms (AAAs) over time, however, with the limited number of channel-to-element connections current footprints are small, which limits the field of view. Moreover, the maximal steering angle of the ultrasound beams in transmit and the maximal receptance angle in receive are insufficient for capturing the curvy shape of the AAA. Therefore, an approach is needed towards large arrays. In this study, high frame rate bistatic 3D US data (17 Hz) were acquired with two synchronized matrix arrays positioned at different locations (multi-aperture imaging) using a translation stage to simulate what a larger array with limited channel-to-element connections can potentially achieve...

Photoacoustic imaging (PAI) is an emerging biomedical imaging technique that combines the advantages of optical and ultrasound imaging, enabling the generation of images with both optical resolution and acoustic penetration depth. By leveraging similar signal acquisition and processing methods, the integration of photoacoustic and ultrasound imaging has introduced a novel hybrid imaging modality suitable for clinical applications. Photoacoustic-ultrasound imaging allows for non-invasive, high-resolution, and deep-penetrating imaging, providing a wealth of image information...

This paper calculates the acoustic shadow zone of the guided wave in a variable thickness plate. The variable thickness plate has a wide range of applications in bridges, ships, etc., and the guided wave is often used for its nondestructive testing. The velocity gradient induced by thickness variations will deflect the guided wave towards lower phase velocities. Both frequency and thickness variation play crucial roles in determining the extent of path bending. In particular, the guided wave can undergo reverse propagation at the non-boundary of the plate...

Numerous quantitative ultrasound imaging techniques have demonstrated superior monitoring performance for thermal ablation when compared to conventional ultrasonic B-mode imaging. However, the absence of comparative studies involving various quantitative ultrasound imaging techniques hinders further clinical exploration. In this study, we simultaneously reconstructed ultrasonic Nakagami imaging, ultrasonic horizontally normalized Shannon entropy (hNSE) imaging, and ultrasonic differential attenuation coefficient intercept (DACI) imaging from ultrasound backscattered envelope data collected during high-intensity focused ultrasound ablation treatment...

In offshore reinforced concrete (RC) structures, the phenomenon of rebar corrosion is widespread, seriously threatening the durability of the structures. However, the issue of rebar corrosion detection especially for the early corrosion situation is also challengeable. It is of great significance to use ultrasonic guided waves (UGWs) for monitoring the situation of the rebar corrosion entire process. In this paper, a mechanical model was used to establish the relationship between different rebar corrosion expansion states and layer-surface contact pressures in the layered RC components with radial cracks...

In this study the Non-Linear Ultrasonic Sideband Peak Count-Index (SPC-I) technique is used as the foundation for anovel approach towards acoustic source localization (ASL) in orthotropic composite plates. The SPC-I based technique proposed here does not require the signal attenuation information or any knowledge on the time of arrival of the signal. It should be noted that since individual sensors can have varying sensitivities, the signal attenuation measured from the recorded signal amplitude is not very reliable...

In micro-scale structures, the influence of scale effects on the mechanical properties cannot be ignored, and the continuum mechanics theory cannot effectively describe guided wave propagation. This paper studies modal displacements in an isotropic micro/nano-scale plate - an essential factor for the mode selection of Lamb waves in non-destructive testing technology. To achieve this, the consistent couple stress theory, which additionally accounts for the impact of scale effects on wave propagation, has to be employed...

Circumferential Shear Horizontal (CSH) guided waves provide an effective method for detecting defects like axial cracks and corrosion in pipes. Periodic Permanent Magnet Electromagnetic Acoustic Transducers (PPM EMATs) are typically used to generate CSH guided waves. However, there is an offset problem to which little attention has been paid. The offset problem refers to the offset of the center (position of maximum energy) of the operating region caused by the variation in the peak frequency of the spatial spectra of PPM with 2 or fewer cycles...

Fatigue cracks often initiate and propagate from edges of structural components. Detection and evaluation of edge cracks could be very challenging, specifically, due to the crack closure phenomenon, which makes fatigue cracks to be partially closed when the applied loading is removed; this usually corresponds to maintenance and NDE inspection conditions. Despite that fatigue crack closure is well investigated, past experimental and theoretical studies related to guided wave-based NDEs largely ignored this phenomenon...

On-demand droplet printing based on piezoelectric micro-jet device (PMJD) is considered a flexible and high-precision method to generate metal droplets directly for flip-chip bonding in industrial electronics. However, the quality of flip-chip bonding is closely related to the height deviation of the solidified droplets (the metal bumps), which is influenced by the complicated hydrodynamics of impacting and oscillation of the droplet with oxide film. Here, the numerical and experimental investigations are first conducted to study the effect of the liquid bridge and deposition parameters on the height deviation of the solidified droplets...

Elastography is a promising diagnostic tool that measures the hardness of tissues, and it has been used in clinics for detecting lesion progress, such as benign and malignant tumors. However, due to the high cost of examination and limited availability of elastic ultrasound devices, elastography is not widely used in primary medical facilities in rural areas. To address this issue, a deep learning approach called the multiscale elastic image synthesis network (MEIS-Net) was proposed, which utilized the multiscale learning to synthesize elastic images from ultrasound data instead of traditional ultrasound elastography in virtue of elastic deformation...

Ultrasonic standing waves with specific wavelengths generated in the multi-layered micro-resonators were numerically and experimentally analyzed. Using a three-dimensional scanning fluorescence microscope, the acoustophoretic motion of fluorescent microparticles within the micro-resonators was carefully and accurately measured. The manufactured micro-resonators were validated by comparing the location of the acoustic pressure nodal plane and the average energy density curves derived from numerical and experimental results...

This paper introduces a methodology to recover the morphology of a complex rough surface from ultrasonic pulse echo measurements with an array of equidistant sensors using the one dimensional convolution neural network (1DCNN). The neural network is trained by the datasets simulated from high-fidelity finite element simulations for surfaces with a range of roughness parameters and is tested on both numerical and real experimental data. To assess the performance of our proposed method, the rough surface reconstruction results from the deep learning approach are compared with those obtained from conventional ultrasonic array imaging methods...

Rayleigh waves travel along the surface of a solid structure, with most of their energy focusing within a depth of one wavelength. Thus, the reflection coefficient from a surface-breaking crack is highly sensitive to the ratio between the crack depth and the wavelength. It is possible to characterize the depth of surface-breaking cracks by measuring the features in the reflected waves. However, a feature value can correspond to multiple depth-wavelength ratios, i.e., the mapping is non-univalent, which brings difficulties for crack sizing using the feature...