Ultrasonic Shear Wave Research Articles

Ultrasonic study of water adsorbed in nanoporous glasses.

Thermodynamic properties of fluids confined in nanopores differ from those observed in the bulk. To investigate the effect of nanoconfinement on water compressibility, we perform water sorption experiments on two nanoporous glass samples while concomitantly measuring the speed of longitudinal and shear ultrasonic waves in these samples. These measurements yield the longitudinal and shear moduli of the water-laden nanoporous glass as a function of relative humidity that we utilize in the Gassmann theory to infer the bulk modulus of the confined water. This analysis shows that the bulk modulus (inverse of compressibility) of confined water is noticeably higher than that of the bulk water at the same temperature. Moreover, the modulus exhibits a linear dependence on the Laplace pressure. The results for water, which is a polar fluid, agree with previous experimental and numerical data reported for nonpolar fluids. This similarity suggests that irrespective of intermolecular forces, confined fluids are stiffer than bulk fluids. Accounting for fluid stiffening in nanopores may be important for accurate interpretation of wave propagation measurements in fluid-filled nanoporous media, including in petrophysics, catalysis, and other applications, such as in porous materials characterization.

Noncontact and rapid measurement of elastic properties of metals with a dual-mode bulk-wave EMAT

ABSTRACT The elastic mechanical behaviour of materials is very important to the design and service safety evaluation of mechanical load components. In order to accurately measure the elastic mechanical behaviour of metal structures with a non-destructive testing way, a dual-mode bulk-wave electromagnetic acoustic transducer (EMAT) is developed for both ultrasonic longitudinal wave and shear wave measurement. The elastic modulus and Poisson’s ratio of metals are directly obtained with the velocities of the longitudinal and shear waves. In order to improve the efficiency of electromagnetic acoustic transducer, the electromagnetic acoustic parameters were characterised and optimised by numerical simulation. The results show that the developed dual-mode EMAT can successfully excite and receive longitudinal and shear waves, and the elastic modulus and Poisson’s ratio of different materials (copper, aluminium and steel) obtained through experiments using the developed dual-mode EMAT are very close to the reference values.

A Scholte wave approach for ultrasonic surface acoustic wave elastography.

Pathological changes in tissues are often related to changes in tissue mechanical properties, making elastography an important tool for medical applications. Among the existing elastography methods, ultrasound elastography is of great interest due to the inherent advantages of ultrasound imaging technology, such as low cost, portability, safety, and wide availability. Although ultrasonic shear wave elastography, as a platform technology, can potentially quantify the elasticity of tissue at any depth, its current implementation cannot assess superficial tissue but can only image deep tissue. To address this challenge, we proposed an ultrasonic Scholte-wave-based approach for imaging the elasticity of superficial tissue. The feasibility of the proposed technique was tested using a gelatin phantom with a cylindrical inclusion. To generate Scholte wave in the superficial region of the phantom, we proposed a new experimental configuration in which a liquid layer was introduced between an ultrasound imaging transducer and the tissue-mimicking phantom. We utilized an acoustic radiation force impulse to excite the tissue-mimicking phantom, analyzed the properties of the generated Scholte waves, and applied the waves for elasticity imaging. In this study, we first reported the observation that Scholte (surface) waves and shear (bulk) waves were simultaneously generated, and they propagated in the superficial and deeper regions of the phantom, respectively. Then, we presented some important properties of the generated Scholte waves. For a 5w/v% gelatin phantom, the generated Scholte waves have a speed of around 0.9m/s, a frequency of about 186Hz, and thus a wavelength of about 4.8mm. The speed ratio between the simultaneously generated Scholte wave and shear wave is about 0.717, which is 15% lower than the theoretical expectation. And we further demonstrated the feasibility of Scholte wave as a mechanism for imaging superficial tissue elasticity. Together with the simultaneously generated shear wave, the Scholte wave was shown to be able to quantitatively image both the background and the cylindrical inclusion (4mm in diameter) of the tissue-mimicking gelatin phantom. This work shows that the elasticity of superficial tissue can be evaluated by utilizing the generated Scholte wave alone, and it also shows that a comprehensive elasticity imaging of the tissue extending from the superficial to deep regions can be achieved by combining the proposed Scholte wave technique and the conventional shear wave technique.

Imaging Concrete Structures with Ultrasonic Shear Waves—Technology Development and Demonstration of Capabilities

Since 1987 when dry-point-contact (DPC) transducers were invented in the USSR, ultrasonic shear wave devices based on those transducers have been commercialized and have become one of the most effective technologies for imaging concrete. That said, the objectives of this paper are (1) to provide a brief review of the historical development of these powerful devices and (2) to provide a comprehensive assessment of their capabilities in imaging internal entities and structural defects. Regarding the former, the paper presents the context that gave birth to DPC technology and different generations of ultrasonic shear wave devices for concrete inspection. For the latter, one of the state-of-the-art ultrasonic shear wave devices (MIRA 3D) was used to collect data on concrete specimens with different built-in flaws/defects. Those data are then visualized with a commonly used data processing algorithm, the so-called synthetic aperture focusing technique (SAFT). Finally, based on the resulting images, the capabilities of the device are discussed in detail for each concrete imaging problem. A main limitation of ultrasonic shear wave technique for concrete inspection is that it requires a significant amount of time and effort for data collection.

Quantifying the Impact of Imaging Through Body Walls on Shear Wave Elasticity Measurements.

In the context of ultrasonic hepatic shear wave elasticity imaging (SWEI), measurement success has been determined to increase when using elevated acoustic output pressures. As SWEI sequences consist of two distinct operations (pushing and tracking), acquisition failures could be attributed to (i) insufficient acoustic radiation force generation resulting in inadequate shear wave amplitude and/or (ii) distorted ultrasonic tissue motion tracking. In the study described here, an opposing window experimental setup that isolated body wall effects separately between the push and track SWEI operations was implemented. A commonly employed commercial track configuration was used, harmonic multiple-track-location SWEI. The effects of imaging through body walls on the pushing and tracking operations of SWEI as a function of mechanical index (MI), spanning 5 different push beam MIs and 10 track beam MIs, were independently assessed using porcine body walls. Shear wave speed yield was found to increase with both increasing push and track MI. Although not consistent across all samples, measurements in a subset of body walls were found to be signal limited during tracking and to increase yield by up to 35% when increasing electronic signal-to-noise ratio by increasing harmonic track transmit pressure.

Plane stress measurement on the cross-section of steel components using ultrasonic shear waves

Plane stress measurement is an important means to obtain the mechanical information of structural steel components. Traditional structural health monitoring techniques are difficult to perform non-destructive measurement of internal plane stress of the components. In this study, we theoretically and experimentally proposed a method for measuring average plane stress on the cross-section of steel components. We derived a new form of plane stress-acoustic relation based on shear wave birefringence and successfully achieved plane stress separation. The phase difference of two groups of echoes was used to calculate effective phase velocity information, where Fourier-transform was used for obtaining the echo phase spectra. The experimental calibration for determining the values of five stress coefficients was presented and the optimal frequency was found to be the center frequency of the probe. The strain gauge method was adopted to prove the effectiveness of the proposed method, and good experimental results were observed.

Optimal design of electromagnetic metamaterial electronic device sensor with specific performance based on multivariate big data fusion

As the basic unit structure of electromagnetic metamaterial, the structure size of open resonant ring directly determines the constitutive parameters of SRR (dielectric constant ε and permeability μ). In order to improve the energy exchange efficiency of the electromagnetic acoustic transducer, the coil backplane of the electromagnetic ultrasonic shear wave sensor was optimized. First, the influence of the thickness of the coil backplane on the ultrasonic signal is studied by the experimental method, and then, the magnetic field distribution of the coil backplane is simulated by the finite element simulation software. Finally, the SNR and lift distance of the shear wave sensor before and after the coil backplane optimization are compared by experiments. In this article, a multi-hypothesis data fusion method in distributed detection system is proposed, which extends the multi-sensor data fusion rules to more general cases. The results show that the optimum thickness of the coil back plate in the electromagnetic ultrasonic transverse wave sensor is 1.5–2.0 mm. Using iron powder with the same length and width as the working area of the coil as the coil backplane can significantly increase the magnetic field strength in the working area of the sensor. Compared with the coil backplane made of non-magnetic materials, the optimized backplane can increase the signal-to-noise ratio of the sensor by about one time and the lift-off distance by about 1 mm.

Evaluation of liver stiffness using ultrasonic shear wave elastography in patients with COVID-19 induced pneumonia.

In patients with COVID-19-induced pneumonia, shear wave elasticity (SWE) was used to assess liver stiffness. This study included 48 cases of COVID-19-induced pneumonia and 48 cases of normal physical examination. Basic and clinical data, including aspartate aminotransferase (AST), were evaluated. Color ultrasonography was used to test the liver's SWE. A biopsy of the liver was also performed. In patients with COVID-19-induced pneumonia, AST and alanine aminotransferase (ALT) levels were higher than those in the control group. Liver SWE showed that liver stiffness is hard (8.745 ± 0.2104) compared with the control group (7.386 ± 0.1521) (P < 0.0001). Pathological biopsy showed that liver inflammation accounted for 89.58%, steatosis accounted for 81.25%, necrosis accounted for 10.42%, and fibrosis accounted for 33.33% in patients with COVID-19-induced pneumonia. ROC curve analysis showed that the SWE is highly sensitive and specific for the diagnosis of liver inflammation and steatosis. The sensitivity was 88.76% and the specificity was 77.01% for the evaluation of liver inflammation. For steatosis, the sensitivity was 90.20%, and the specificity was 78.40%. The SWE of liver is useful to assess liver function and pathological status in COVID-19 patients.

Fatigue state characterisation of steel pipes using ultrasonic shear waves.

The phenomenon of the reduction in the propagation speed of an ultrasonic wave when it travels through a fatigue zone has been well studied in the literature. Additionally, it has been established that shear waves are more severely affected by the presence of such a zone, compared with longitudinal waves. Our study utilises these phenomena to develop a method able to characterise the fatigue state of steel pipes. Initially, the existing theory regarding the increased sensitivity of shear waves to the presence of fatigue is validated through measuring and comparing the change in propagation speed of both longitudinal and bulk shear waves on flat geometries, at different fatigue states. The comparison is achieved with the aid of ultrasonic speed C-scans of both longitudinal and shear waves, with the latter now being obtainable through our implementation of advances in Electromagnetic Acoustic Transducers (EMAT) technology. EMATs have not been traditionally used for producing C-scans, and their ability do to so with adequate repeatability is demonstrated here; we show that shear wave scanning with EMATs now provides a possibility for inspection of fatigue damage on the inner surface of pressure-containing components in the nuclear power industry. We find that the change in ultrasonic wave speed is amplified when shear waves are used, with the magnitude of this amplification agreeing well with the theory. Following the verification of the theory, the use of EMATs allowed us to tailor the shear wave scanning method to pipe geometries, where C-scans with conventional piezoelectric transducers would not have been possible, with the results successfully revealing the presence of fatigue zones.

Reference installation for measuring acoustic parameters of solids

The issues of providing working standards of the 1st category of metrological organizations of the country with regard to modern needs in the field of ultrasonic measurements in solids are considered. There is presented a modernized reference installation designed for precision measurements of propagation velocities of longitudinal and shear ultrasonic waves and damping coefficient of longitudinal ultrasonic waves in solids. Measurements of acoustic parameters of solid media are made by pulse-echo and resonance methods using contactless broadband capacitive methods of excitation and registration of ultrasonic waves. This installation is used as working standard of the 1st category in accordance with the state verification schedule for measuring instruments of the propagation velocities and damping coefficient of ultrasonic waves in solids. The technical means included in the installation (mechanical and electronic parts) have been improved, analog measuring means have been replaced with digital ones, methods for measuring acoustic parameters of solids based on the use of digital measuring means have been developed and the thickness range of installed ultrasonic measures has been expanded. The composition and main components of the reference installation, the used measurement methods and the principles of operation of the installation in various operating modes are described. The technical and metrological characteristics of the installation are given. Sources of measurement error (uncertainty) were analyzed. The field of application of the results is high-precision measurements of the acoustic characteristics of solid media, metrological ensuring of ultrasonic non-destructive testing and diagnostics.

Acoustic Birefringence Changes in the Base Metal and Heat Affected Zone of ASTM 1020 Steel under Plastic Deformation and Fatigue

This paper deals with metallographic studies and ultrasonic investigations of acoustic birefringence in the base metal and heat affected zone of welded specimens of ASTM 1020 steel under uniaxial tension and low-cycle fatigue. We examined microstructural changes on the surface using optical microscope. It was found that development of slip bands differs in the base metal and heat affected zone. The ultrasonic pulse echo method was used for the determination of acoustic birefringence and velocities of ultrasonic shear waves. The differences in the change in velocities in the base metal and in heat affected zone were revealed. Acoustic birefringence was found to change monotonously in the base metal under fatigue as well as in the base metal and heat affected zone under uniaxial tension. For heat affected zone, during fatigue, acoustic birefringence was found to change non-monotonously up to cycle ratio of 0.3 and decrease monotonously after cycle ratio of 0.3. Based on the relationship between relative number of loading cycles, or plasticity resource, and acoustic birefringence, ultrasonic techniques were proposed for assessing damage.

Effect of frequency on the evaluation of the concrete defects by ultrasonic shear wave tomography

Effect of frequency on the evaluation of the concrete defects by ultrasonic shear wave tomography

Effect of frequency on the evaluation of the concrete defects by ultrasonic shear wave tomography

Effect of frequency on the evaluation of the concrete defects by ultrasonic shear wave tomography

TEMPERATURE DEPENDENCE OF ACOUSTIC BIREFRINGENCE OF SHEAR ELASTIC WAVES IN POLYCRYSTALLINE ALUMINUM

The article presents the results of a study of the temperature dependences of the shear elastic waves velocity of polycrystalline aluminum alloy AD0 in the temperature range from 20 °C to 45 °C. For the studied material the temperature dependence of the acoustic birefringence parameter characterizing the a shear ultrasonic wave splitting into two orthogonally polarized waves propagating at different velocities is determined. The calculation of the acoustic birefringence parameter was carried out according to the data of the propagation time precision measurement of shear elastic waves (the measurement error of the propagation time is 1-2 ns), polarized along and across the direction of rolling. Theoretical studies have shown that for materials with weak anisotropy, the temperature dependence of the acoustic birefringence parameter is mainly related to the influence of temperature on the elastic anisotropy of the crystals that make up the polycrystalline material and the characteristic of the crystallographic texture – the coefficient of the orientation distribution function W420. Corrections to the value of the birefringence parameter with temperature change are given. It was experimentally obtained that the acoustic birefringence parameter increases by 9% with increasing temperature, which must be taken into account by using it as a diagnostic parameter to evaluation changes in the characteristics of static and fatigue strength. An algorithm is proposed for estimating the prediction of the temperature dependence of the acoustic birefringence parameter of a single-phase material when the crystallographic texture changes as a result of plastic deformation, for example. A good coincidence of the predicted temperature dependence of the acoustic birefringence parameter with the experimental one was obtained – the deviation error of the calculated curve from the experimental one was 0.2–2% in the temperature range of 20 °С to 45 °С.

ON THE ISSUE OF LIVER BIOPSY IN PATIENTS WITH METABOLICALLY ASSOCIATED FATTY LIVER DISEASE

The aim of the work was to evaluate the possibility of replacing liver biopsy with other methods of examination in patients with metabolically associated fatty liver disease. All patients were examined according to a single diagnostic algorithm consisting of four stages: physical, laboratory, instrumental (using non-invasive bioimpedansometry, multiparametric ultrasound examination, dual-energy X-ray absorptiometry in the "Whole body" mode, computer and magnetic resonance imaging), histological (evaluation of liver micropreparations on the SAF scale). the patients were divided into three groups, taking into account the results of histological examination of biopsies on the SAF scale: group 1 – patients with hepatic steatosis without signs of inflammation, fibrosis (n = 56, 53.9%); group 2 – patients with steatohepatitis and clinically insignificant hepatic fibrosis F0-F1 (n = 30, 28.8%); group 3 – patients with steatohepatitis and clinically significant liver fibrosis F2-F3 (n = 16, 15.4%). the correlation of findings obtained by the histological examination of liver biopsies and the data of ultrasound quantitative liver steatometry is high – r = 0.95 (for liver steatosis S1), r = 0.84 (for liver steatosis S2), r = 0.91 (for liver steatosis S3); ultrasonic shear wave elastography – r = 0.84 (for clinically insignificant liver fibrosis F0-F1), r = 0.88 (for clinically significant liver fibrosis F2-F3). the data obtained using dual-energy X-ray absorptiometry in the "Whole Body" mode quantitatively reflect the state of the patient's metabolic status, they can be evaluated in dynamics due to low radiation load. Thus, the diagnostic complex consisting of assessing the level of hepatic transaminases, multiparametric ultrasound examination and dual-energy X-ray absorptiometry in the "Whole body" mode is optimal to examine the patients who have contraindications to liver biopsy or completely refuse to pass this study. in case of the patient's consent, absence of contraindications, as well as in the presence of a number of diffuse liver diseases, histological examination is recommended to identify and to assess in detail the dystrophic, inflammatory, sclerotic, regenerative processes.

Pricking-cupping therapy for cervical spondylotic radiculopathy with qi stagnation and blood stasis based on Young's modulus value

To compare the clinical effect between pricking-cupping therapy and acupuncture-cupping therapy on cervical spondylotic radiculopathy (CSR) with qi stagnation and blood stasis, and to evaluate the trapezius muscle objectively and quantitatively with ultrasonic shear wave elastography (SWE). A total of 70 patients with CSR of qi stagnation and blood stasis were randomly divided into a pricking-cupping group (35 cases) and an acupuncture-cupping group (35 cases). In both groups, Dazhui (GV 14), Jianjing (GB 21), C5-C7 Jiaji (EX-B 2), positive sensitive points, etc. were selected. In addition, the patients in the pricking-cupping group were treated with pricking-cupping therapy, seven-star needle was used to tap the acupoints and positive sensitive points, and cupping was added after slight bleeding. The patients in the acupuncture-cupping group were treated with conventional acupuncture and cupping. Both groups were treated once every other day, three times a week, for two consecutive weeks. The difference of Young's modulus value, pain visual analogue scale (VAS) score and neck disability index (NDI) score were observed before treatment, after the first treatment, after one-week treatment and after two-week treatment, and the efficacy was evaluated in the two groups. At each time point after treatment, the difference of Young's modulus value, VAS scores and NDI scores in the two groups were lower than those before treatment (P<0.001). Except for the NDI score after two-week treatment, all the indexes in the pricking-cupping group were lower than those in the acupuncture-cupping group (P<0.001). The total effective rate was 91.4% (32/35) in the pricking-cupping group, which was higher than 68.6% (24/35) in the acupuncture-cupping group (P<0.05). The pricking-cupping therapy could improve trapezius muscle elasticity, relieve pain and improve cervical function in patients of CSR with qi stagnation and blood stasis, which is more effective than acupuncture-cupping therapy.

Assessment of the Ulnar Collateral Ligament of the Elbow Using Ultrasonic Shear Wave Elastography in Professional Baseball Players.

Injury to the ulnar collateral ligament (UCL) of the elbow can cause chronic pain and loss of throwing ability. Ultrasonic shear wave elastography (SWE) is a new imaging method that can be used for quantitative assessment of tissue elasticity. To evaluate the properties of the UCL in professional baseball players using SWE. Cross-sectional study; Level of evidence, 3. This study included 35 professional baseball players (mean age, 23.0 years) without elbow injuries. Both elbows of each player were examined using ultrasound, and comparisons between the dominant and nondominant arms were conducted. The thickness of the anterior bundle of the UCL at its midportion was measured in the resting position on ultrasound. We also measured the difference in the ulnohumeral joint space with and without gravity stress on the forearm. Tissue elasticity was evaluated using a built-in software program. The relationship between UCL elasticity and ultrasound findings was analyzed using the Pearson correlation coefficient. The mean ± SD thickness of the UCL was significantly greater in the dominant arm versus the nondominant arm (6.0 ± 1.4 vs 5.3 ± 1.3 mm; P = .004). The mean joint space difference was significantly wider in the dominant arm as compared with the nondominant arm (0.81 ± 0.42 vs 0.52 ± 0.31 mm; P = .002), and the mean UCL elasticity was lower in the dominant arm than in the nondominant arm (34.9 ± 11.6 vs 43.3 ± 10.6 kPa; P = .002). UCL elasticity was negatively correlated with UCL thickness (r = -0.27; P = .02) and joint space difference (r = -0.34; P = .003). In professional baseball players, the elbow UCL of the dominant arm demonstrated increased thickness, with a larger joint space gap on gravity stress and lower elasticity in SWE as compared with the nondominant arm. Greater medial joint laxity can be predicted by assessing the elasticity of the UCL using SWE.

Dynamic mechanical characteristics of aged silicone rubber blend

The effect of aging on the mechanical properties of silicone rubber (SR) was investigated by means of ultrasonic, dynamic mechanical analysis, and FTIR techniques. Both longitudinal and shear (Ultrasonic wave velocities) were measured at room temperature and at frequencies of 2 MHz. Density, molar volume, ultrasonic wave velocities, tensile strength, mechanical properties, and FT–IR showed the improvement of the silicone rubber network with aging time from 0 to 70 days, while loosening of the network structure was observed at 14 days and 50 days aging. These behaviours were explained in terms of the change in cross-link density and average stretching force constant of bonds with aging. Thermogravimetric analysis and differential scanning calorimetric techniques showed quite low thermal stability and temperature performance for aged SR at 14 and 50 days than virgin SR which was confirmed by the cracks and voids appeared under scanning electron microscope.

Laser ultrasonic loading and optical interference detection of closed cracks in K9 glass.

The traditional optical detection method has a limitation in detecting closed cracks in optical elements. In this Letter, a novel, to the best of our knowledge, method has been developed for the detection of closed cracks in transparent samples. Firstly, behaviors of closed cracks under ultrasonic waves loading are demonstrated through the finite-element method (FEM). Simulation results show that the crack can be opened by the laser ultrasonic shear wave (S-wave). Then, a Mach-Zehnder interferometer system is experimentally established to detect closed cracks under ultrasonic waves loading in the sample. It is demonstrated that closed cracks which cannot be detected by interferometry become visible in interferogram images under ultrasonic waves loading. The width of the opened crack can also be quantitatively estimated. Thus the method would be a promising approach to detect initially closed cracks in optical elements.

Characterization of the elastic modulus of ceramic–metal composites with physical and mechanical properties by ultrasonic technique

Abstract The scope of this study, that is, the effect of the elastic modulus obtained by ultrasonic method on the physical and mechanical properties of tungsten carbide (WC)-based ceramic–metal composites, which have Ni and Co metallic binder composition produced by powder metallurgy and represented by high strength and hardness criteria, was investigated. In order to obtain composite samples in the study, it was sintered in a microwave furnace at different temperatures to combine the powder particles prepared at the rate of 60% Ni, 20% Co, and 20% WC by weight. Then, the velocities and longitudinal attenuation values of longitudinal and shear ultrasonic waves along the composite sample were measured using the ultrasonic pulse-echo method. The elastic modulus of the composites was determined using ultrasonic velocities and sample density. Hardness testing, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analyses were also performed. The results show that the elastic modulus increases with the increase in sintering temperature and ultrasonic wave speeds, but decreases with the longitudinal attenuation value, considering the SEM images and XRD analysis. There is also a linear relationship between elastic modulus and stiffness.