Ultrasonic Wave Propagation Research Articles

Active sensing ultrasonic guided wave-based damage diagnosis via stochastic stationary time-series models

In the context of acousto-ultrasonic guided wave-based structural health monitoring, a statistical damage detection and identification (collectively referred to as damage diagnosis) framework for metallic and composite materials is proposed. Stochastic stationary time-series autoregressive (AR) models are used to model the ultrasonic wave propagation between piezoelectric actuator-sensor pairs on structural components and enable the damage diagnosis process via the use of the AR estimated parameters and corresponding covariance matrices. The proposed method exploits guided wave signals including the reflection parts, and thus the extraction of the S0 and/or A0 modes is not necessary, while the statistical properties and variation of estimated model parameters with respect to damage intersecting and non-intersecting wave propagation paths are presented and assessed. To investigate the method’s performance and robustness, two variations are proposed based on the singular value decomposition and principal component analysis. The obtained modified AR parameter vectors are then used to estimate appropriate statistical characteristic quantities used to enable the damage detection and identification tasks. The diagnosis is based on properly defined statistical hypotheses decision-making schemes and predetermined type I error probabilities. The performance and applicability of the method are explored experimentally via a series of tests on aluminum and composite coupons under various damage scenarios for damage intersecting and non-intersecting paths. The results of the present study demonstrated the effectiveness and robustness of the proposed modeling and diagnostic framework for guided wave-based damage diagnosis that can be implemented in a potentially automated way.

Porosity dependence of sound velocities in partially sintered alumina, zirconia, ATZ, and mullite ceramics

AbstractYoung's modulus and sound velocities of partially sintered alumina, zirconia, ATZ, and mullite ceramics with a broad range of porosities determined via the impulse excitation technique (IET) and the ultrasonic wave propagation pulse‐echo technique (UPT) are found to be in good agreement and exhibit sigmoidal curves as a function of the sintering temperature. The porosity dependence of the relative values of Young's modulus and sound velocities is either close to or below (but never above) the prediction based on an exponential relation, and none of them is significantly below the prediction based on a percolation relation or a recently proposed numerical benchmark relation for overlapping monosized spheres. Values are lower when concave pores or irregular anisometric grains are dominating. The correlation of the normalized longitudinal wave velocities and relative transverse wave velocities, with VL/VT ratios ranging from 0.50 to 1.91, is well predicted by models for Poisson's ratios between 0.35 and 0.2.

Investigation and optimization of ultrasound-assisted process of carbon dioxide absorption into amine-based nanofluids

In this study, the effect of the simultaneous application of the nanofluids and ultrasound waves on the carbon dioxide (CO2) absorption process has been investigated in a batch system. For this purpose, the methyl diethanolamine (MDEA)-based nanofluids containing zinc oxide (ZnO) nanoparticles were prepared through a two-step procedure and used as the liquid absorbents. The absorption experiments were carried out using the pressure drop method in an isothermal reactor equipped with a high-frequency (1.7 MHz) ultrasound transducer. The effects of various factors, including the temperature, initial pressure, MDEA concentration, nanoparticle concentration, and ultrasonic power upon the absorption process, were investigated using the design-of-experiments (DOE) method. At first, a parameter screening was applied to determine the significant factors affecting the process. After removing the insignificant parameters, the process optimization was performed using the response surface method (RSM). The results indicated that the employment of high-frequency ultrasound waves had a great effect on improving the CO2 absorption rate. By using a small amount of ultrasonic power (3.9 W), the absorption rate was increased by 632%. The results of the screening revealed that among the mentioned input factors, the effects of the ultrasound power, MDEA concentration, and initial pressure on the process were significant, and the effects of the other factors were insignificant. Based upon the results, among the input factors, the ultrasonic power had the greatest impact on the CO2 absorption rate. The results also revealed that the utilization of ZnO nanoparticles in the ultrasound-assisted process of CO2 absorption, could lead to a slight reduction in the absorption rate, resulting from attenuation of the ultrasonic wave propagation in the liquid due to the presence of nanoparticles. The results of RSM optimization demonstrated that the best model to describe the process behavior was the quadratic model. A polynomial relation was also presented in terms of the factors affecting the process. Additionally, the optimal values of the input factors were determined to attain the maximum absorption rate by using RSM optimization.

Simulations and experimentation of ultrasonic wave propagation and flaw characterisation for underwater concrete structures

ABSTRACT Ultrasonic non-destructive evaluation of concrete submerged in water is a complex phenomenon that has important implications for the durability and safety of marine structures such as bridges, piers and offshore platforms. The scattering of ultrasonic waves inside concrete materials with aggregate size comparable to the ultrasound wavelength often limits the interpretation of inspection results. To enhance the understanding of ultrasonic wave propagation inside the underwater concrete, numerical simulations using the finite element method (FEM) with the Transient Acoustics-Piezoelectric Interaction application mode of Multiphysics software package have been developed. This study focuses on developing a 2D numerical model to reproduce and illustrate the propagation of ultrasound in seven types of underwater concrete test blocks with various types of inclusions and voids embedded inside it. The B-Scan 2D images of the concrete test blocks were acquired using the simulated data and compared with experimental results acquired using an in-house developed four-channel ultrasonic imaging system. Both simulation and experimental results showed a good resemblance, indicating that B-Scan imaging can be applied to identify and characterise various types of defects and inclusions in underwater concrete structures, providing better assessment of the material than conventional ultrasonic pulse velocity (UPV) method.

Experimental study on ultrasonic wave propagation characteristics of gas-liquid two-phase flow in riser annulus

Deepwater drilling projects face challenges such as delays in gas kick monitoring and a high risk of well control failure. How to monitor gas kicks as early and accurately as possible is one of the keys to preventing significant accidents such as well blowouts. Monitoring gas kicks at risers is a promising method for early monitoring of gas kicks in deepwater drilling. In this paper, by constructing an experimental device for ultrasonic gas kicks monitoring of the riser, the response law of the ultrasonic signal to the gas-liquid two-phase flow was tested under different air intake, drill pipe rotation speeds, and liquid flow rates. This was done by constructing an experimental riser ultrasonic gas kick monitoring device. The signal-to-noise ratio and the root-mean-square error are used as measurement standards, and the wavelet threshold noise reduction method is used to reduce noise-containing signals. The ultrasonic sensitivity characteristics of the gas-liquid two-phase flow are demonstrated by analyzing the signal in the time domain and frequency domain: peak amplitude, attenuation coefficient, wave velocity, and fundamental frequency. A non-linear relationship exists between peak amplitude, fundamental frequency, and air intake, whereas an approximately linear relationship is evident between the attenuation coefficient and wave velocity with air intake. A quantitative characterization relationship between ultrasonic characteristic parameters and air intake was obtained by conducting a multiple regression analysis using the least-squares method on the attenuation coefficient, wave velocity, fundamental frequency, and air intake. Experiments demonstrate that the relative error between the actual air intake of 86.4 % of the test data group and the theoretical air intake determined based on the quantitative characterization relationship is less than 10 %.

Effects of coral aggregate properties on the ultrasonic pulse velocity of concrete

For the non-destructive evaluation of concrete properties and internal damage monitoring, the ultrasonic pulse velocity (UPV) method has been widely employed; however, for coral concrete, crucial characterization parameters such as UPV are still unknown. Thus, this paper focuses on coral concrete UPV characteristics, especially with respect to porosity and compressive strength. The results show that the coral aggregate has diverse morphologies and complex internal structure, which greatly affects the homogeneity of its UPV, which ranges from 2550–3850 m/s, and these are also the main reason for the UPV dispersion effect in coral concrete. Due to the lower UPV of coral coarse aggregate, the UPV of coral mortar was higher than that of coral concrete in the same condition. In addition, the three-dimensional of large-aggregate distribution in coral concrete had a remarkable effect on ultrasonic wave propagation path in coral concrete. It was also found that the coral concrete porosity, compressive strength and UPV are strongly correlated specifically the compressive strength and UPV are linearly positively correlated. The UPV of coral concrete in the dry state is approximately 3950–4450 m/s and its porosity is approximately 14.3 %–21.5 %, and the relationship between the two is more reliably characterized by an exponential function. Furthermore, the linear correlation between coral concrete strength and UPV can be effectively improved by reducing aggregate particle size, thus, the strength can be inferred by the UPV method within a certain range.

Recognition of mineralogical and technological varieties of iron ore on the basis of ultrasound backscatter spectrograms

The research is aimed to the analysis and modeling of the process of propagation of ultrasonic waves in iron ore samples to assess its mineralogical varieties. The paper analyzes domestic and foreign experience in modeling of ultrasonic waves propagation; methods of mathematical and computer modeling were used, as well as methods of mathematical statistics and probability theory for analysis of the results. Scientific novelty consists in developing and substantiating a method for recognizing the mineralogical and technological varieties of iron ore of a developed deposit based on spectrograms of a backscattered ultrasonic probing signal. Practical valueconsists in developing a methodology for non-contact non-destructive mineralogical analysis of iron ore to improve the efficiency and quality of its further processing and preparation for metallurgical processing. results. As measurable characteristic estimates of textural and structural features of iron ore varieties the results of spectral analysis of the reversed radiant ultrasonic signal were used. To implement the measurement results classification procedure, Adaptive Neuro-Fuzzy Inference System is used. At the vector of parameters of membership functions of terms of input variables and the vector of coefficients of linear functions in the conclusions of the rules was formed based on the characteristics of the processed ore and the spectrograms of the backscattered ultrasonic signal. The average accuracy of recognition of magnetite, chlorite-carbonate-magnetite, hematite-magnetite, magnetite-cummngtonite-chlorite-siderite mineral varieties of iron ore of the studied deposit was 93%.

Features of propagation of lateral transverse ultrasonic wave in a flat layer of material

The features of propagation of ultrasonic pulses of a lateral transverse wave from a point source of vibrations on the surface of the layer are considered. The mechanism of transformation of this wave during reflections from the boundaries of the layer into a transverse wave beam directed to the surface of the layer at an angle close to 45° is described. Experimental confirmation of the excess of the amplitudes of the lateral wave signals over the signals of other waves propagating in the layer is presented.

Modelling of ultrasonic vibration-assisted forming considering the distribution of ultrasonic field with structure deformation

Ultrasonic vibration-assisted (UVA) forming is typically used to promote the forming quality of complex structures due to the acoustic-plastic effect. Ultrasonic vibration (UV) is always applied via the contact of tools with the structure surface; thus a distribution of ultrasonic field exists owing to the propagation and attenuation of ultrasonic waves, which may vary with structural deformation. This makes the prediction and control of ultrasonic effect extremely difficult in achieving high forming quality. To develop a new coupling model considering the interaction between ultrasonic field and deformation field, UVA tensile experiments of superalloy sheet were performed first. The experimental results demonstrated that UV had a local effect on the tensile specimen, resulting in non-uniform distribution of temperature, strain and dislocation density. During the modelling, the intensity of ultrasonic field was quantified by acoustic energy density, which can be calculated using vibration velocity. A dislocation-based constitutive relation was also established, in which ultrasonic-related functions were introduced to reflect the effect of ultrasonic field on structural deformation. Then, a sequential coupling modelling method was proposed. Through the cyclic calculation of ultrasonic field and deformation field, the simulation of UVA forming considering the distribution of ultrasonic field with structure deformation was realised. With the coupling model, the non-uniform distribution of deformation accompanied by a non-uniform ultrasonic field during UVA forming was revealed. When applied to a complex W-bending process, the targeted softening effect on the W-bending specimen was precisely predicted. The coupling model is expected to lay a foundation for the optimisation and control of the UVA forming process.

Features of Propagation of Lateral Transverse Ultrasonic Waves in a Flat Layer of Material

Features of Propagation of Lateral Transverse Ultrasonic Waves in a Flat Layer of Material

Localization and classification of scattered nonlinear ultrasonic signatures in bio-mechanical media using time reversal approach.

This paper deals with the time reversal approach along with signal classification using ϕ-divergences in biomedical applications for localization and statistical classification of ultrasonic nonlinearities. The time reversal (TR) approach in combination with nonlinear elastic wave spectroscopy (NEWS) is used to obtain the nonlinear signature of air bubbles with different sizes and ultrasound contrast agents in a liquid. An optimized chirp-coded signal in the range of 0.6-3 MHz is used as a compression coding. The signal classification is performed using the fuzzy classification method and the divergence decision tree algorithm using specific ϕ-divergence spectral measures extracted from the received ultrasonic response containing acoustic nonlinearities. The classification results prove that different types of nonlinearities extracted with classical "pulse inversion" based coding methods can be identified. Simultaneously, the different positions of scattered sources are distinguished by ϕ-divergence methods. The potential of time reversal nonlinear elastic wave spectroscopy methods for understanding of ultrasonic wave propagation in complex media is clearly exhibited.

Evaluation of the Uniaxial Compressive Strength of Gneiss from Southern Togo from Non-Destructive Tests

The mechanical and physical characteristics of rocks hold significant importance across various realms of research and engineering, particularly in the field of Civil Engineering. The utilization of rocks as construction materials hinges on several of their mechanical traits (Los Angeles, Micro Deval under water presence, Young's Modulus, Compression Strength) as well as physical attributes (homogeneity, porosity, etc.). Tests for determining certain of these characteristics are expensive, challenging, and time-consuming. Among these attributes, mention can be made of determining compression strength, which necessitates substantial equipment for proper sample preparation. This renders the process very costly, laborious, and leads to the complete destruction of samples during experimental measurements. Our objective in this study is to assess the uniaxial compression strength of gneiss from southern Togo using non-destructive testing. This would help mitigate the relatively high costs associated with this test. To address this issue, the development of new methods for determining this test using non-destructive testing approaches is necessary. Among the most commonly used reference techniques for characterizing materials and determining their physical and mechanical properties are non-destructive evaluation techniques based on ultrasonic wave propagation and rebound hammer testing. The adopted methodological approach involves the collection of rock samples (amphibole and biotite gneiss) from 33 sites in southern Togo, their proper sampling, and the execution of various tests on the obtained samples. The obtained results have facilitated the examination of several approaches, notably the ANFIS model (Adaptive Neuro-Fuzzy Inference System) and the MLR model (Multiple Linear Regression), for predicting the uniaxial compression strength value based on the sclerometer index and the ultrasonic wave propagation velocity (in parallel or perpendicular orientation to the foliations). It emerges from the ANFIS model, combining ultrasonic waves in the perpendicular orientation to the foliations and the sclerometer index, that the uniaxial compression strength can be predicted with an R² of 0.9884, an RMSE of 2.9271, a MAPE of 1.160, and a VAF of 98.83. In comparison, the MLR model yields an R² of 0.9832, an RMSE of 3.686, a MAPE of 1.402, and a VAF of 98.22. The derived ANFIS models can be utilized to estimate the uniaxial compression strength of gneiss in Togo and beyond. Keywords: Gneiss, Non-destructive Testing, Sclerometer Index, Ultrasonic, Compression Strength.

Using acoustic testing to estimate strength and stiffness of wood-polymer composites

This study used non-destructive testing with ultrasonic and stress wave propagation to evaluate bending strength and stiffness of wood-polymer composites. Twelve composite plate products were produced with different formulations of polymer matrix (high- and low-density polyethylene and polypropylene) and type and proportion of flour (coconut shell and wood). Mechanical and acoustic properties were influenced primarily by the type of matrix used in the composite. The greater the proportion of wood and coconut shell flour the higher the wave propagation velocity, stiffness, and strength. We found a correlation between mechanical properties (strength and stiffness) and wave velocity and stiffness coefficient. We also present linear regression equations of the stiffness and strength of the specimen as a function of wave velocity and stiffness coefficient obtained through non-destructive testing. For polypropylene and high-density polyethylene matrix composites, the stiffness coefficient provided a better estimate of stiffness, while for low-density polyethylene the wave velocity provided better results.

Systematic investigations on frequency mixing response of ultrasonic shear horizontal and Rayleigh Lamb waves

The study of self- and cross-interactions of shear horizontal (SH) waves has garnered significant attention in the field of nonlinear ultrasonic practice. This interest stems from the potential high sensitivity of SH waves to microdamage and their low out-of-plane attenuation characteristics. However, due to the dispersive nature and intricate mechanisms governing guided wave propagations and interactions, the nonlinear responses of SH waves, particularly the third-order harmonic generation and wave mixing with Rayleigh Lamb (RL) waves, remain largely unexplored. This study presents a comprehensive investigation into the ultrasonic harmonic wave generation of SH guided waves. The research approach combines theoretical considerations and finite element modeling to investigate and discuss guided wave mixing involving SH and RL waves. Six cases of phase-matched wave mode pairs are developed based on deduced synchronism and symmetry conditions. A nonlinear material constitutive model, encompassing both the third- and fourth-order elastic constants, is incorporated into the simulation. The results of the numerical analysis reveal the existence of newly generated higher and combined harmonic waves in an intuitive manner. Specifically, the interactions between ultrasonic SH and RL guided waves are observed to generate second- and third-order combined harmonic waves at the mixing frequencies under internal resonant conditions. The nonlinear waves have a cumulative effect during the mixing period, with their amplitude remaining constant after passing through the mixing zone. This study provides the first observation of mode conversion and third-order combined harmonic generation of SH waves. The insights gained from the numerical perspective offer understandings of the frequency mixing response of SH waves.

Physical and dynamic characteristics of high-amplitude ultrasonic wave propagation in nonlinear and dissipative media

This study presents a comprehensive investigation into the soliton solutions for the Khokhlov–Zabolotskaya–Kuznetsov ([Formula: see text]) problem using the Bernoulli sub-equation function approach, generalized Kudryashov method, and Homotopy perturbation method. The [Formula: see text] equation, a nonlinear wave equation that governs the propagation of high-amplitude ultrasonic waves through nonlinear media, is studied in detail. Perturbation theory and asymptotic expansions are employed to derive approximate solutions for the [Formula: see text] problem. These methodologies offer valuable insights into the behavior of ultrasonic waves in different media, thereby facilitating the optimization of ultrasonic transducer design and enhancing the precision of ultrasonic imaging systems. The analytical and semi-analytical methods utilized for solving the [Formula: see text] equation are computationally efficient and serve as valuable resources for researchers and engineers working in the field of ultrasonics. The outcomes of this study carry significant implications for the understanding of ultrasonic wave behavior in nonlinear and dissipative media, ultimately contributing to the development of more accurate and efficient ultrasonic imaging techniques.

Quantitative detection and evaluation of Rayleigh ultrasonic wave for fatigue crack on turbine blade surface

In this paper, different characteristics of micro-cracks on the surface of turbine blades have been successfully evaluated based on the detection of Rayleigh ultrasonic wave by numerical simulation and experimental study. The quantitative relationship between the maximum amplitude of Rayleigh ultrasonic wave and the features of cracks including width, depth, excitation position, and inclination angle was established. Numerical calculations of different curvature models show that curvature has no significant effect on the propagation of Rayleigh ultrasonic wave. According to the developed multi-functional ultrasonic equipment, cracks on complex surfaces can be detected by clamping two probes on the arc guide rail. The experimental results verify the validity of the numerical simulations. It gives an excellent basis for the effective automatic detection of cracks on the surface of turbine blades. This research provides a suitable method and new equipment for rapid quantitative inspection of turbine blades.

3D Hybrid Modeling for the Ultrasonic Phased Array Inspection of Porosity in Heavy Plates: Simulation and Experimental Validation

Quantitative non-destructive testing (NDT) modelling and simulation tools are important in design and fabrication of ultrasonic phased array (UTPA) sensors with optimum characteristics and reduce the number of experimental efforts and development time. In order to achieve high accuracy with a low computational time in the simulation, the modeling tools require not only the high-frequency approximation of the ultrasonic wave propagation but also the high-precision electro-acoustic coupling model. In this work, an application specific 4 MHz, 32-element linear phased array probe with an optimized angle beam wedge for the inspection of porosity in heavy plates was developed based on the new 3D hybrid modeling approach. As a first step, we performed the FEA modeling of an UTPA sensor, which includes the full 1-3 piezo-composite design with the arrangement of array elements, conducting electrodes, multi-phase damping material, acoustical matching layer and the electrical circuit of a 50 Ω coaxial cable. In addition, the real excitation pulse of an industrial UT equipment was included in the current modelling to achieve the high accuracy in the simulated result. In the second step, the FEA simulated pulse-echo characteristics of an array element were further used as the reference signal in the CIVA-UT Software to simulate the imaging of porosity in heavy plates, quantitatively. Furthermore, the 3D wedge-geometry of the array sensor was modeled and optimized to suppress the unwanted wedge-boundary reflected echoes and to improve the signal-to-noise ratio (SNR) in the detected signals. The 3D hybrid model simulated Time Corrected Gain (TCG) curves for the 3 mm SDH at different depths in the reference steel plate were compared with the real experiments and a good quantitative agreement was achieved.

Comparison of grain structure models for wave propagation analysis in centrifugally cast stainless steel

Centrifugally cast stainless steel (CASS) is widely used in primary coolant piping of pressurized water reactor plants because of its high corrosion resistance and high strength. An in-service inspection based on ultrasonic testing (UT) has to be conducted for weld joints of primary coolant piping on the basis of JSME Rules on Fitness-forService for Nuclear Power Plants. However, it is difficult to detect and size flaws in CASS components with high accuracy because of the following reasons: Ultrasonic waves are scattered and attenuated due to coarse grains, and anisotropic and heterogeneous properties in CASS lead to ultrasonic beam skewing. Numerical simulations are useful and reasonable ways for better understanding the ultrasonic wave propagation behavior in CASS. To effectively achieve this, the simulation model should include a three-dimensional (3D) grain structure. In this study, we modeled three kinds of the solidification grain structures of centrifugally CASS. One is obtained by using a cellular automaton method, another consists of many hexagonal columns with the same dimensions, and the other is transversely isotropic material. Then these structures were fed into an explicit finite element model for simulating wave propagation and the simulated results were compared with those measured by a laser Doppler vibrometer. Through the comparison, we investigated the applicability of these three kinds of solidification grain structure models to simulation for wave propagation.

Quantitative analysis and evaluation of the optimization method of transformer partial discharge ultrasonic sensor monitoring

Abstract Accurate partial discharge (PD) measurement is critical to ensure the stable operation of transformers. The ultrasonic method is a low-cost, safe, and reliable technology that is widely available and provides real-time monitoring capability. The PD ultrasonic signals propagation is complex and severely attenuated in the transformer, which greatly affects the measurement accuracy of the sensor. In order to improve the accurate monitoring of PD in complicated transformer environments, an optimization monitoring method based on sub-scene detection and quantitative analysis and evaluation is proposed in this paper. Firstly, to address this concern, a sub-scene monitoring method is designed and explores the optimal monitoring points separately. In addition, establish the partition model of an oil-immersed power transformer, and compare the ultrasonic wave propagation characteristics and sound pressure attenuation characteristics of different monitoring points. Then, analyzed by wavelet transform algorithm and Pearson correlation coefficient to determine the best monitoring point location for each scene. Finally, we further tested the proposed method through extensive experiments based on simulations, testbed, and trial deployment. The experimental results have demonstrated the feasibility and accuracy of the proposed method in transformer PD monitoring under complicated environments.

Experimental study on damage law of liquid CO2 cyclic freeze–thaw coal

In order to study the damage characteristics of coal under liquid CO2 (LCO2) cyclic freeze-thaw (F-T), ultrasonic detector and infrared thermal imaging technology were used to discuss the ultrasonic wave propagation of coal and the surface temperature evolution law of coal samples during LCO2 cyclic F-T. The nuclear magnetic resonance technology was used to study the pore structure evolution of coal body. The results show that the velocity of primary wave and secondary wave is reduced. The more cycles, the lower the minimum temperature of coal side and end face. The temperature difference at different points on the same measuring line is large, indicates that the heterogeneity of coal sample under the same temperature causes anisotropy of heat transfer inside the matrix. The pore structure changes greatly under the LCO2 cyclic F–T action. With the increase of the number of cycles, the proportion of adsorption pores decreased, the proportion of seepage pores increased, and the pore volume increased，the total porosity and effective porosity showed an exponential upward trend, the bound porosity showed an exponential downward trend, indicating that LCO2 cyclic F–T is conducive to the increase of crack volume and the improvement of crack connectivity.