Amplitude Of Ultrasonic Waves Research Articles

Study on Ultrasonic Characteristics and Prediction of Rock with Different Pore Sizes

The internal defects of rocks are the main cause of instability and failure in underground engineering. Therefore, using ultrasonic monitoring technology to study the defect characteristics of rocks containing voids is of great significance. The research results indicate that with the increase in the pore size, the longitudinal wave velocity and first wave amplitude of rocks containing voids decrease, the attenuation coefficient increases, and the difference in ultrasonic parameters between rocks containing voids and intact rocks increases, resulting in a significant decrease in the rock integrity. The propagation of ultrasonic waves in porous rocks can be divided into three stages, where obvious ultrasonic reflection, diffraction, and scattering occur. The attenuation of sound pressure is significant, and the ultrasonic sound pressure is negatively linearly correlated with the pore size. Based on the amplitude, velocity, and pressure of ultrasonic waves, an ANN-based method for predicting the pore size of rocks is proposed, which inverts and predicts the pore size of rock masses with high prediction accuracy.

Experimental verification of a translation model of linear transfer function of ultrasonic vibrations with nonlinear wave modulation for detection of contact-type failures

Contact-type failures, such as the crack closure at the tip of a fatigue crack, closed delamination of composite materials, and loosening of bolted joints, are difficult to detect through nondestructive inspections using linear ultrasonic waves or vibrations. When low-frequency vibrations, such as environmental disturbances, operating vibrations, and vibrations excited by actuators, are applied to a structure with contact-type failure, the contact condition of the failure surface fluctuates in synchronization with the low-frequency vibration. The amplitude and phase of ultrasonic waves or vibrations through contact-type failure with fluctuating contact conditions are modulated in synchronization with low-frequency vibrations, that is, realizing nonlinear wave modulation. Previous reports have presented evaluation and localization methods of contact-type failure using amplitude and phase demodulation signals. In this study, amplitude and phase demodulations were affected by the change in the viscous damping of a structure. Therefore, the essence of nonlinear wave modulation was considered to be the fluctuation of the natural frequencies. In this study, a visualization experiment of the fluctuation of natural frequencies caused by nonlinear wave modulation was conducted. The time-varying transfer function was reconstructed by measuring the amplitude and phase demodulation signals with the change in the excitation frequency. Moreover, the translation model of the transfer function of the ultrasonic vibration with nonlinear wave modulation was evaluated.

Process Optimization and Environmental Analysis of Ultrasound-Assisted Biodiesel Production from Pangasius Fat Using CoFe2O4 Catalyst.

This study optimized biodiesel synthesis from Pangasius fat using a Box-Behnken experimental design. The manipulation of key variables included the CoFe2O4 catalyst dosage, the methanol-to-fat molar ratio, and the ultrasonic wave amplitude. We determined optimal conditions for biodiesel synthesis through the central runs, resulting in a remarkable 96.5% yield. The produced biodiesel exhibited diverse fatty acid compositions and met specifications for viscosity, specific gravity, acid value, and iodine value. Furthermore, we conducted a comprehensive life cycle assessment (LCA) to shed light on the environmental implications of the process. The LCA revealed a minimal global warming potential of 0.21 kg CO2 per kg of biodiesel produced, demonstrating the environmental viability of the entire process. These significant findings highlight the promising potential of using Pangasius fat as a sustainable feedstock for biodiesel production. Additionally, they provide valuable insights into developing ecologically friendly energy sources.

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.

Optimization design of laser-EMAT and its application in high-temperature forgings detection

In high-temperature continuous forging process, according to the real-time monitoring of workpiece thickness and flaws, the processing parameters can be adjusted accordingly, so we can remove defective components in time, which has essential research value for avoiding the interruption of production line and improving their yield and quality grade. We established a finite element (FE) model of the carbon steel’s laser-electromagnetic acoustic transducer (laser-EMAT) testing process. Based on the simulation model, we analyzed the effects of laser parameters, EMAT parameters, and sample thickness on the detected ultrasonic signal amplitude, and we also achieved the optimized Laser-EMAT design parameters. Subsequently, we developed a high-temperature resistant spiral coil EMAT and measured the high-temperature forging with a thickness of 100 mm and temperatures from 300 °C to 730 °C. Based on the experiments, we researched the effect of specimen temperature on the received ultrasonic wave amplitude. The results show that the excitation efficiency of laser-induced ultrasonic waves improves by decreasing pulse duration, decreasing laser spot radius, and increasing pulse laser energy. The receiving efficiency of the shear wave (SW) detected by the EMAT enhances when reducing the diameter of the EMAT wire and increasing the permanent magnet height. When the radius of the permanent magnet is equal to the radius of the EMAT coil, the receiving efficiency of SW is the highest. As the sample thickness increases, the size of the EMAT should increase accordingly to the acoustic beam divergence for obtaining a higher ultrasonic wave intensity. The amplitude of the SW signal received by the EMAT increases by 679% after the optimization design. With rising carbon steel forging temperature, the SW signal amplitude increases first and then decreases sharply, reaching its maximum at 617 °C, which is 29% higher than at room temperature, and the signal-to-noise ratio (SNR) of the SW is 20.5 dB.

Holographic generation of arbitrary ultrasonic fields by simultaneous modulation of amplitude and phase

Acoustic holograms have been used widely to generate desired acoustic fields. Following the rapid development of 3D printing technology, the use of holographic lenses has become an efficient method to produce acoustic fields with high resolution and low cost. In this paper, we demonstrate a technique to modulate the amplitude and phase of ultrasonic waves simultaneously using a holographic method with high transmission efficiency and high accuracy. On this basis, we generate an Airy beam with high propagation invariance. We then discuss the advantages and disadvantages of the proposed method when compared with the conventional acoustic holographic method. Finally, we design a sinusoidal curve with a phase gradient and a constant pressure amplitude and realize transport of a particle on a water surface along a curve.

Optimisation of Rayleigh wave Laser-EMAT with the application of surface constraint mechanism

ABSTRACT A laser-electromagnetic acoustic transducer (Laser-EMAT) Rayleigh wave (RW) detection based on surface constraint mechanism and its optimisation design are proposed to solve the low signal-to-noise ratio (SNR) of its application in aluminium alloy detection at high-temperature. We established a finite element (FE) model of aluminium alloy’s Laser-EMAT RW detection process based on the surface constraint mechanism and investigated the effect of the surface constraint mechanism on laser-excited RW . We also studied the effects of laser parameters and meander-line coil (MLC) EMAT parameters on the ultrasonic wave amplitude and spectral composition. Finally, the enhancement effect of the surface constraint mechanism on RW amplitude was analysed by Laser-EMAT RW detection experiments on aluminium alloy at room temperature and high temperatures. The results show that the optimised MLC-EMAT can increase the RW amplitude by 1.97 times. When the laser line source width equals the MLC-EMAT turn spacing, the echo SNR is the highest. The enhancement effect of the surface constraint mechanism on the RW amplitude gradually decreasesas the specimen temperature increases. The RW amplitude can increase by 1.43 times when the surface constraint mechanism is applied at room temperature, and for the aluminium alloy specimen at 430°C, the RW amplitude can increase by 32%.

接触剛性によるボルト締結モデルと透過超音波パルスを用いた定量評価

Evaluation of bolt tightening plays an important role to keep a performance of a mechanical structure. Lack of the fastening force induces slack and falling of the tightening bolt. Excessive fastening force induces a plastic deformation of screw thread and causes the decline of the fastening force. Therefore, guarantee of the bolt tightening is an important subject in order to secure the mechanical structure against unforeseen accidents. However, most of preceding studies are restricted within qualitative evaluation of the slackness. In the field of industrial manufacturing, quantitative evaluation of the bolt tightening is strongly required. In this paper, the authors propose a technique for quantitative evaluation of bolt tightening, and in this technique, the flank of the screw thread is assumed to contact through a contact stiffness. The transmissivity and reflectivity of an ultrasonic pulse wave through the flank are derived as a function of contact stiffness, and the contact stiffness is capable of being identified from experimentally acquired amplitude of ultrasonic pulse wave. The contact stiffness is quantitatively identified and the surface pressure on the screw thread is estimated by the identified contact stiffness through the results of the preceding study. The proposed technique treats an ultrasonic pulse perpendicularly transmits a fastening bolt, and is applied to an experimentally acquired ultrasonic pulse which enters a side surface of nut and transmits a bolt-nut fastening element. The identified contact stiffness is shown to be adequate for the given fastening force to the bolt-nut fastening element, and validity of the proposed technique is demonstrated.

XPS study on ultrasonic nitridation of graphite using high-frequency (1.64 MHz) sound wave

Nitrogen-doped graphene (N-doped graphene) has attracted tremendous attention as a metal-free and low-cost catalyst for the oxygen reduction reaction; however, its synthesis involves energy intensive processes and complex chemical reactions. This study is the first attempt for nitriding graphite powder through one-pot ultrasonication to develop a process for the mass production of nitrogen-doped (N-doped) graphene. Graphite powder was irradiated with high-frequency (1.64 MHz) ultrasonic wave in 10 % ammonia solution. The volume concentration of fine graphite in the solution after the irradiation process increased approximately three times compared to the solution containing graphite powder without irradiation. The XPS analysis revealed that graphite powder was directly nitrided by ultrasonic irradiation in spite of the fact that the nitrogen‑carbon concentration N/C was less than 0.1. Pyridinic-N bonding configuration was formed. The N/C ratio increased with increasing the irradiation time from 15 to 90 min. Increasing the voltage amplitude of ultrasonic wave accelerated the nitridation. The oxidation of graphite proceeds simultaneously with the nitridation process.

Contactless ultrasonic method for determining knitted fabrics tension

The values of the measured amplitudes of ultrasonic vibrations that have passed the controlled material have been obtained. These values were compared with the amplitude of the waves passing through the fabric sample when the initial tension was applied to it. After that, the total current value of the tension of each sample of the knitted fabric in its three zones was determined. The distribution of the total tension in different zones of the sample material was also determined. It has been established that the amplitude of ultrasonic waves passing through different zones of the textile material can be used to determine the tension of the knitted fabric over the entire width of its fabric. The possibility and expediency of determining the fabric tension on knitting equipment by using the ultrasonic contactless method has been shown. The tension of the knitted fabric in its manufacture is the main technological parameter, the value of which determines the physical, mechanical and consumer properties of the finished fabric, especially basis weight. The use of operational technological control of the tension of knitted fabrics directly during their production will improve the quality of finished products, and, accordingly, the reliability of use in personal protective equipment, in particular in body armour. It has been proposed to determine the tension of knitted fabrics in their production on knitting equipment by changing the amplitude of ultrasonic waves passing through the material under the action of tension, which also changes during the movement of the process equipment. The proposed contactless method is quite promising, since it has a number of significant advantages over the existing contact methods. In the course of the research, experimental measurements of the amplitude of ultrasonic waves have been carried out. These waves passed through samples of fabric of various materials while stretching. The samples of knitted fabrics were irradiated with an ultrasonic pulse signal with a wave frequency of 40 kHz. The samples of knitted fabrics from 58x2 Tex Kevlar threads and high molecular weight 44x3 Tex polyethylene yarns with double weave 1x1 elastic have been taken as a basis for the research. For textile fabrics, the structure of which does not allow stretching through pores under the action of tension, it is necessary to additionally adjust the contactless sensors in frequency and capacity depending on the corresponding sample. The values of the measured amplitudes of ultrasonic vibrations that have passed the controlled material have been obtained. These values were compared with the amplitude of the waves passing through the fabric sample when the initial tension was applied to it. After that, the total current value of the tension of each sample of the knitted fabric in its three zones was determined. The distribution of the total tension in different zones of the sample material was also determined. The dependences of the amplitude of ultrasonic waves, transmitted through the textile material in its different zones, on the value of the total tension, and on the value of the distribution of the tension of the fabric over its entire width were obtained. The deviations δP of the tension display between the determination of this parameter by the standard and ultrasonic methods are shown. The deviations δU between the amplitudes of waves passing through different zones of the controlled fabric are also determined.

Ultrasonic Synthesis of Nanochitosan and Its Size Effects on Turbidity Removal and Dealkalization in Wastewater Treatment

A detailed study on the synthesis of chitosan nanoparticles under ultrasonication is reported in this paper. By using this simple technique, chitosan particles in nanometer range can be easily prepared without using any harmful and expensive chemicals. The results show that increasing the ultrasonic irradiation time and ultrasonic wave amplitude are the key factors for producing discrete chitosan nanoparticles with narrow particle size distribution. The resulting nanoparticles show superior turbidity removal efficiency (75.4%) and dealkalization (58.3%) in wastewater treatment than the bulk chitosan solid (35.4% and 11.1%, respectively), thus offering an eco-friendly and promising approach for treating wastewater via the coagulation/flocculation process.

The effect of ultrasonic wave amplitude on the physical properties of zinc oxide (ZnO) deposited by ultrasonic spray method

In this study, high quality zinc oxide (ZnO) thin films, with improved properties, were prepared by a cost-effective ultrasonic spray pyrolysis technique via a careful optimization of the used ultrasonic wave amplitude. The deposition process was performed on glass substrate and were subsequently annealed at 400 °C. We investigated the effect of various ultrasonic wave amplitude on the structural, surface morphology, optical and electrical properties of the obtained thin films, after varying the applied wave amplitude. Furthermore, deposited thin films were studied by means of XRD, UV–vis spectrophotometer, scanning electron microscope, and four-point probe technique. XRD analysis confirmed that obtained ZnO thin films have polycrystalline structure and a wurtzite (hexagonal) phase, with a c-axis preferred orientation (002). The crystallite size was about 23–30 nm. The SEM micrographs of the surface morphology show uniform, homogenous and dense films with granular structures. The films thicknesses were found to be dependent on the used wave amplitude; they were ranged from 184 to 423.5 nm. In addition, the optical properties of the deposited thin films reveal that the films are highly transparent in the visible region above 80%, while the value of energy band gap varies from 3.24 to 3.27 eV. The Electrical properties investigation revealed a resistivity around 10-3 Ω.cm, showing also a non negligible dependency with the wave amplitude tuning. We obtained an improvement in the carrier concentration (1.6 × 1020–3.9 × 1020 cm−3) and mobility (4.2–15 cm2/V.s) with the ultrasonic wave amplitude rising. High quality ZnO thin films with enhanced properties are in demand and have a large wide of applications in optoelectronics and solar cells.

Performance degradation detection of 12CrMoV steel by magneto-acoustic compound inspection method

The performance degradation of 12CrMoV steel generally occurs under a long-term working period in a high-temperature environment. In order to improve the reliability of a single nondestructive testing method for the performance degradation analysis of 12CrMoV steel, an advanced magneto–acoustic compound inspection method, in which pulsed eddy current (PEC) and ultrasonic waves were obtained from a single electromagnetic acoustic transducer (EMAT) testing signal, was adopted. The magneto–acoustic compound inspection method was carried out on 12CrMoV steel plates heat-treated at different temperatures and times. New parameters, including the slope and peak value of PEC, and the amplitude and attenuation of ultrasonic waves, were introduced to evaluate the performance degradation of 12CrMoV steel. It was found that ultrasonic waves manifested higher sensitivity than eddy current when the microstructure changed significantly. Therefore, the magneto–acoustic compound inspection method is advantageous for evaluating the performance degradation of 12CrMoV steel.

Nano-emulsification of oriental lacquer sap by ultrasonic wave propagation: Improvement of thin-film characteristics as a natural resin

Lacquer sap has received much attention as a traditional natural resin because it is a renewable and eco-friendly biopolymer resource unlike artificial coating materials. However, strict drying conditions and long drying times of lacquer sap should be modified to expand its applications. This study presents the first attempt to investigate the effect of different amplitudes of ultrasonic waves on the lacquer sap composed of water-in-oil (W/O) emulsion droplets and the mechanical properties of the resultant film by solvent evaporation. Acoustically induced cavitation via batch ultrasonication facilitates the generation of submicron-sized W/O emulsion. The drying time of sonicated lacquer sap was noticeably shortened as the amplitude of acoustic power increased. Interestingly, the transparency of the film cast from lacquer sap consisting of the smallest emulsion droplets increased significantly, weakening the degree of colour change from caramel-like yellow to dark brown as polymerisation progressed. These are attributed to the effective and frequent contact of laccase enzyme with urushiol at the increased interfacial area of nano-emulsified W/O droplets pulverised by ultrasonic waves. The quinone radical-generation in the interface layer and its transfer to the urushiol oil phase through water-insoluble glycoprotein emulsifier are greatly promoted, resulting in highly cross-linked, dense three-dimensional polymer networks, which also increased the lacquer film hardness after drying. As the emulsion droplet size decreased, the mutual interaction between the catechol moiety of urushiol and the substrates increased, resulting in improved adhesion. The nano-emulsification of the lacquer sap by ultrasonic waves can be used in a simple, effective, and eco-friendly way to shorten the drying time and improve the film characteristics of natural resins. This approach could pave the way for its wide range of applications in industrial fields, taking into account green and sustainable chemistry.

Linear and Nonlinear Ultrasonic Techniques for Monitoring Stress-Induced Damages in Concrete

Abstract When stress in concrete exceeds certain threshold value, microcracks are nucleated, these microcracks can propagate and coalesce forming macrocracks, resulting in the gradual decay of the mechanical properties of concrete and eventual failure of the concrete structures. For safety concerns, one needs to develop suitable nondestructive testing methods capable of detecting past overloads of concrete structures during its service life. In this work, the stress-induced damage in concrete is monitored using ultrasonic techniques, exploiting the coupling between the stress level experienced by concrete and its wave propagation parameters. Cyclic compression tests with increasing maximum load level have been performed on specimens made of concrete with coarse-grained (CG) aggregates. Experimental results have been analyzed by two different ultrasonic methods—the linear and the nonlinear ultrasonic techniques. In linear ultrasonic technique, the stress level experienced by the specimens is related to the variations in signal amplitude and velocity of ultrasonic waves. In nonlinear ultrasonic method, the sideband peak count (SPC) technique is used for revealing the stress-induced damage corresponding to each load step. In comparison to linear ultrasonic parameters, the nonlinear ultrasonic parameter SPC-I appears to be more sensitive to the variations of the internal material structures during both loading and unloading phases. Moreover, the SPC technique has shown to be capable of identifying both the initial damage due to the evolution and nucleation of microcracks at the microscopic scale, and the subsequent damages induced by high overload, resulting in an irreversible degradation of the mechanical properties.

Determination of biodiesel purity through feature mapping to the multi-dimensional space by the LS-SVM approach

Purity is one of the essential properties of biodiesel. Since the purity parameter depends on different operating conditions, its direct measurement is too hard and can only be obtained for specific ranges of conditions. Therefore, this work considers the least-squares support vector machines (LS-SVMs) that transform operating conditions to a multi-dimensional space to simulate biodiesel purity in wide ranges of operating conditions. Indeed, we develop a reliable LS-SVM approach for modeling the biodiesel purity as a function of catalyst type and its concentration, reaction time, temperature, methanol-to-oil volume ratio, frequency, and amplitude of ultrasonic waves. The designed LS-SVM’s predictive performance is compared with four available artificial intelligence (AI) techniques in reliable literature. The obtained results confirm that the LS-SVM paradigm outperforms other considered AI-based techniques regarding five different statistical criteria. Our LS-SVM model provides AARD = 2.2%, RMSE = 3.46, and R2 = 0.9868 for the prediction of 267 experimental data points, which includes 267 data points. This model is finally employed for investigating the effect of different influential variables on biodiesel purity.

The Law of Response of Propagation Time and Amplitude of Ultrasonic LCR Wave in the Elastic-Plastic Deformation of X70 Steel

The Law of Response of Propagation Time and Amplitude of Ultrasonic LCR Wave in the Elastic-Plastic Deformation of X70 Steel

In-situ prediction of α-phase volume fraction in titanium alloy using laser ultrasonic with support vector regression

A laser ultrasonic based non-contact detection method combined with support vector regression (SVR) was proposed for the first time for in-situ predicting the volume fraction of α-phase in titanium alloy (Ti-10V-2Fe-3Al). The alloy specimens were heated with incremental temperatures from 820 to 1100 °C to obtain different microstructures and volume fraction of α-phase, and the nonlinear relationship between the parameter of Rayleigh ultrasonic wave (velocity, amplitude and peak frequency) and the volume fraction of α-phase was established and analyzed by the combination of laser ultrasonic experiment and metallographic analysis. The SVR, with ultrasonic parameters and heat treatment parameters (heating and cooling rate, holding time and holding temperature) as input features, was implemented to predict the volume fraction of α-phase, achieving a relative mean error less than 5%. The results indicate that the SVR-based laser ultrasonic technique can be applied as a reliable and effective method for in-situ characterization of volume fraction of α-phase in titanium alloy.

ДОСЛІДЖЕННЯ ЗГАСАННЯ УЛЬТРАЗВУКОВИХ ХВИЛЬ ПРИ ЇХ ПРОХОДЖЕННІ ТА ВІДБИТТІ ВІД ОДНОШАРОВИХ МАТЕРІАЛІВ З ПОРАМИ РІЗНОГО РОЗМІРУ

Research of attenuation of ultrasonic waves in various single-layer materials with available pores of different sizes changes in this work. The above is necessary for the possibility of creating non-contact means of ultrasonic testing of such materials. In the work to analyze the processes of interaction of ultrasonic waves with single-layer materials and various changes depending on the thickness or basis weight of the material. Expressions are given for the modules of the complex coefficient of transmission and reflection of ultrasonic waves from single-layer materials with small pores, as well as from textile single-layer materials with through pores, through which most of the vibrations pass. The dependences of relative changes in the amplitude attenuation of waves on the oscillation frequency, thickness and basis weight of the material are given. It is shown that the attenuation of the amplitude of ultrasonic waves that interact with single-layer materials with small pores, and the damping of vibrations for single-layer textile fabrics can be very different from each other. This difference is caused by the bending of part of the sound waves of the fibers of textile fabrics with through pores during the interaction of vibrations. The dependences of the relative changes in the difference of the modules with and without attenuation are obtained for the complex reflection and transmission coefficients of ultrasonic waves. These vibrations interacting with single-layer materials with different pores are considered taking into account the frequency of ultrasonic waves, pore sizes, thickness or basis weight of the material itself. The obtained dependences for determining the attenuation of the amplitude of the probe ultrasonic waves on the structure, porosity of the material, its thickness or surface density. This will allow to create non-contact control tools for materials with complex internal structures and automatically configure them to change pore sizes, which can significantly affect the errors of such devices. The accuracy of the devices that will be tuned to the complex structure of the monolayer material being controlled will be affected precisely by the attenuation parameter of the probe oscillations. In the future, this line of research will make it possible to create non-contact methods and means of monitoring the technological parameters of various single-layer materials and integrate such devices and systems directly into the production process.

Treatment of olive wastewater by using sonocatalytic oxidation and synthesis of activated carbon supported catalysis systems

Olive mill wastewater (OMW) generated by the olive oil extracting industry is a major pollutant, because of its high organic load and phytotoxic and antibacterial phenolic compounds which resist biological degradation. Mediterranean countries are mostly affected by this serious environmental problem since they are responsible for 95% of the worldwide olive oil production. The aim of this study was to purify the high toxic substance by using advanced oxidation techniques using sonocatalytic oxidation method. For these processes, TiO2/AC, WO3/TiO2/AC, V2O5/TiO2/AC and WO3/V2O5/TiO2/AC nanoparticles were synthesized on activated carbon (AC). Then, Using the catalysts obtained in the experimental studies, changes of the lignin and Chemical Oxygen Demand (COD) in OMW were investigated depending on the pH of the suspension, the amount of catalyst, the initial concentration and the ultrasonic wave amplitude. Optimum values for these parameters were found as pH = 10, 1.5gL−1 WO3/TiO2/AC, 250 mL/L of concentration, 60% of amplitude, respectively.