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In this study, the stability of water-emulsified diesel (WED) prepared by different methods have been analyzed. In first phase, the optimum condition of Hydrophilic-Lipophilic Balance (HLB) value of the surfactant used for the preparation of emulsified diesel with respect to its stability has been determined. Different resultant HLB values have been obtained by mixing two surfactants in different proportion. The highest emulsion stability (ES) is found for WED prepared with the surfactant mixture of HLB value 8 which is obtained by mixing 65.5% Span 80 and 34.5% Tween 80. In second phase, WEDs containing 10% water and 2% surfactant mixture with resultant HLB value 8 have been prepared using mechanical homogenization as well as ultrasonication methods. In third phase, the emulsions are prepared adding 10, 20, and 30% water and 2% surfactant mixture with resultant HLB value 8 using ultrasonication process. The emulsion mixture has been kept in a cooled water bath to minimize hot spot effect during ultrasonication process. The polydispersity index (PDI), water particle size and auto correlation factor (ACF) of all four prepared WEDs have been measured by nano particle analyzer which works on dynamic light scattering (DLS) technique. These properties of the WEDs have been analyzed to investigate their stability behavior of the emulsion. Experimental investigations have also been carried out on performance and emission characteristics of a single cylinder, four-stroke diesel engine using WED prepared by both methods containing 10% water. At full load, the brake thermal efficiency is found to be marginally higher using emulsified diesel prepared using ultrasonicator compared to base diesel. The NOx and smoke emissions have been found to be lower for both types of emulsified diesel than pure diesel. The experimental results show more favorable emulsification, performance and emission characteristics for the emulsified diesel prepared by ultrasonic machine than that prepared by mechanical homogenizer. The density, viscosity, and calorific value of the emulsions prepared by the two methods have also been measured and compared with that of neat diesel. [ABSTRACT FROM AUTHOR]

To improve the ultrasonic energy and realize far-field ultrasonic abrasive machining of complex surfaces, a spherical-array-focused ultrasonic abrasive machining system was established. By combining ultrasonic field simulation, detection and a single-factor experiment, the influences of the ultrasonic generator current, abrasive concentration, and particle size on the material removal properties and surface quality evolution of quartz glass were investigated. When the current was less than 0.4 A, the material removal showed plastic removal at the nanoscale. When the current was more than 0.5 A, the cavitation phenomenon formed micron-scale impact removal traces on the workpiece surface. The increase in abrasive concentration increased the impact density and material removal rate, while excessive abrasive concentration increased the impeding effect between abrasive particles and reduced the material removal rate. Moreover, the increase in abrasive particle concentration enhanced heterogeneous cavitation nucleation, promoted the removal of abrasive impact materials under the action of a cavitation jet, and inhibited the removal of direct surface cavitation. The abrasive particle size affects the heterogeneous cavitation nucleation and the acceleration of the cavitation jet on abrasive particles, which affects the material removal rate and surface quality. By controlling the energy of the focused ultrasound and abrasive parameters, the plastic or brittle domain removal of quartz glass can be achieved at the micro- and nanoscales. [ABSTRACT FROM AUTHOR]

This research is focused on the drilling of Nickel based super alloy with diamond metal core drill and identified the significant parameters of rotary ultrasonic machining that optimise the machining rate (MR) and surface quality. Four general parameters: workpiece material, workpiece thickness, tool material, and tool size; and four RUM parameters: tool rotational, feed rate, ultrasonic power rating, and abrasive grit size of the tool were tested against and surface quality of the cut. The results indicated that the maximum value of MR of 0.8931mm3/sec is acquired at higher level of tool rotation, feed rate, ultrasonic power and moderate level of abrasive grit size of diamond. The minimum surface roughness (Ra) 0.554 µm is observed at higher level of rotational rotation, Moderate value of feed rate, ultrasonic power and diamond abrasive grit size. In addition, for single-objective and multi-objective functions, the particle swarm optimization (PSO) approach is used to find the optimum values for process parameters. Furthermore, a scanning electron microscope is also utilized to check the machined surface after RUM. It is concluded that microcracks are observed on the machined surface. [ABSTRACT FROM AUTHOR]

Amorphous alloys are a new type of multi-functional advanced material with the properties of general metal materials and glass, which are also called metallic glasses. They have good comprehensive properties, such as a wide application range, low cost, and high reusability. Using reasonable process parameters, non-traditional machining can not only realize the machining of complex amorphous parts, but also avoid the crystallization and oxidation of amorphous alloys, realizing tasks that cannot be accomplished by traditional machining. Therefore, this review systematically summarizes the research status and development potential of amorphous alloys fabricated using non-traditional machining methods. First, we introduce the principles of laser machining, ultrasonic machining, electrical discharge machining, electrochemical machining, and other non-traditional machining methods for amorphous alloys. Subsequently, the influence of the machining parameters and other external conditions on the machining effect is summarized. The machining cost, machining efficiency, and environmental impact of these non-traditional machining methods were compared. Finally, non-traditional machining technology for amorphous alloys is summarized and discussed. • The processing principles of non-traditional machining methods are summarized. • The influences of processing parameters on the machining effect are reviewed. • Costs, effects, and pollution of non-traditional machining are compared. • The limitations or shortages of non-traditional machining methods are summarized. [ABSTRACT FROM AUTHOR]

To solve the problems of high cutting forces, severe tool wear, and poor surface integrity faced by advanced materials in aerospace manufacturing, multi-dimensional vibration machining (MDVM) is receiving unprecedented attention. MDVM utilizes workpiece and/or tool vibration excited in different directions to achieve high quality and efficient machining of aeronautical hard-to-cut materials. This paper covered typical MDVM hardware systems based on different vibration mechanisms, vibration application methods, and control methods, discussed the machining mechanisms such as friction reversal and contact-separation, and displayed the application effects in extending tool life, improving surface integrity, and manufacturing functional surfaces. The diversity of vibration mechanisms and the complexity of vibration modes of the MDVM system made it difficult to develop a unified design method for vibration systems and to demonstrate the machining mechanism under the coupling of different ultrasonic-induced effects. Therefore, it is an important development direction for future research to investigate the vibration and machining characteristics of MDVM systems and reveal the unified law. [ABSTRACT FROM AUTHOR]

Conventional surface grinding can be divided into up grinding and down grinding according to rotation direction of spindle. Nevertheless, the effects and differences of ultrasonic vibration on the two machining methods have been less reported. The influence of ultrasonic vibration amplitude on cutting force, surface roughness and surface topography were investigated in this paper by conducting tangential and radial ultrasonic vibration assisted down/up grinding comparison experiments on SiC. The results showed that the grinding force of down grinding was less than that of up grinding in conventional grinding, while the surface roughness was greater than that of up grinding. The grinding forces of both down grinding and up grinding were reduced to different ratios after applying different ultrasonic vibration, while the surface roughness increased. The grinding force of up grinding decreased and then increased with the increase of amplitude, while the grinding force of down grinding kept decreasing and the surface roughness decreased. The reasons for the differences in cutting forces and surface quality between the two grinding methods after the application of ultrasonic vibration are discussed. By observing the surface morphology, the percentage of ductile area on the machined surface decreases and then increases with the increase of amplitude. [ABSTRACT FROM AUTHOR]

Rotary ultrasonic machining (RUM) is an effective method of high-quality and high-efficiency machining for advanced composites. However, the machining mechanism and kinematic characteristics of ultrasonic machining of SiC particles-reinforced aluminum matrix (SiC p /Al) composites are yet unclear, limiting the applications of RUM in composites machining. In this study, a rotary ultrasonic vibration-assisted scratch (RUVAS) test was designed for the high-volume fraction of SiC p /Al composites. The kinematic and scratch force model of RUVAS was developed to describe the scratch process of SiC p /Al. Both RUVAS and conventional scratch (CS) tests were performed under various scratch speeds on SiC p /Al. The scratch trajectory was divided into three modes: continuous, semi-continuous, and intermittent. We observed the formation of different surface morphology under different modes. The scratch force difference between RUVAS and CS was insignificant when the scratch speed is high, which indicated that the effect of ultrasonic vibration diminished at a high speed when the ultrasonic frequency was fixed. When assisted by ultrasonic vibration, the scratch morphology of SiC p /Al indicated that the matrix has undergone significant plastic deformation. While the hard SiC particles tended to be ruptured and pressed into the plastic matrix, this mechanism can effectively suppress the initiation and propagation of cracks, which is beneficial to reducing the stress influence zone, healing the surface defects, and improving the surface integrity. The subsurface morphology indicates that the subsurface damage under CS and RUVAS mainly includes particle cracking, matrix tearing, and interface failure. Our experimental result shows that ultrasonic vibration can effectively reduce the subsurface damage of SiC p /Al composites, bringing insight into fundamental mechanisms of ultrasonic machining and providing guidance for the vibration-assisted processing of SiC p /Al composites. [ABSTRACT FROM AUTHOR]

Ultrahigh-temperature ceramic matrix composites are currently among the most promising high-temperature-resistant materials, owing to their high-temperature strength, high-toughness and excellent corrosion resistance; they are widely used in national defense and aerospace fields. However, it is a difficult material to machine, and high precision is difficult to achieve using traditional machining methods. Nontraditional machining methods are not constrained by material physical and mechanical properties, and good surface quality is easily obtained, which is an important direction in the field of ultrahigh-temperature ceramic matrix composites. This paper summarizes the recent nontraditional machining methods utilized in the fabrication of ultrahigh-temperature ceramic matrix composites. Firstly, various nontraditional machining methods for ultrahigh-temperature ceramic matrix composites based on borides, carbides and nitrides are reviewed, and the machining performances under different machining conditions are compared. Subsequently, the problems and challenges of ultrahigh-temperature ceramic matrix composite nontraditional machining are summarized and discussed. Lastly, the future development path of nontraditional machining methods for ultrahigh-temperature ceramic matrix composites is summarized and predicted. [ABSTRACT FROM AUTHOR]

The printability of artificial defects inside the additively manufactured laser powder bed fusion (LPBF) 316L stainless steel is investigated. The printing parameters of the LPBF process are optimized to produce artificial defects with reproducible sizes at desired positions while minimizing redundant porosity. The smallest obtained artificial defect is 90 μm in diameter. The accuracy of the geometry of the printed defect depends on both the height and the diameter in the input model. The effect of artificial defects on the very‐high‐cycle fatigue (VHCF) behavior of LPBF 316L stainless steel is also studied. The specimens printed with artificial defects in the center are tested under VHCF using an ultrasonic machine. Crack initiation is accompanied by the formation of a fine granular area (FGA), typical of VHCF. Despite the presence of relatively large artificial defects, FGA formation is observed around accidental natural printing defects closer to the surface, which can still be considered as internal. The causes for this occurrence are discussed. [ABSTRACT FROM AUTHOR]

Ceramic rock slab is a kind of new material with the advantages of high hardness, wear resistance, and high-temperature resistance, and it is widely used in industry and households. However, problems such as easy chipping and serious tool wearing occurred in conventional grinding (CG). To overcome these challenges, this work introduces rotary ultrasonic grinding (RUG) in processing ceramic rock slabs. Study the theoretical motion trajectory of single abrasive grain and the removal mechanism of hard and brittle materials in RUG, and analyzed the influence of amplitude on cutting force in finite element simulation of single abrasive grain. A comparative process experiment of RUG and CG was performed on the hole processing of ceramic rock slabs. The experimental results showed that compared with CG, the cutting force and chipping area of RUG were reduced by 40.4 and 14.3%, respectively. The cutting force and chipping area decreased with the increase of the spindle speed and increased with the increase of the feed speed. With the increase of ultrasonic amplitude, the cutting force and chipping area decreased gradually, and the tool wear rate decreased from 0.54 to 0.10%, which effectively suppresses the spalling of abrasive grains on the surface of the tool and extends the life of the tool. [ABSTRACT FROM AUTHOR]

The vibration characteristics of a giant magnetostrictive transducer play a significant role in the stability and processing effect of spinning ultrasonic machining. The output characterization of the giant magnetostrictive transducer is unstable subject to an powerful external load, which severely restricts the application of giant magnetostrictive transducer in industry. In this study, the effect of change of load force and electrical parameter in the different directions on the high-frequency (about 20 kHz) vibration output characteristics of the giant magnetostrictive transducer is investigated, through finite element analysis and static loading experimental. The result shows that the electrical parameter of a giant magnetostrictive transducer has a similar changing trend with the increasing of the axis and radial force load; The resonant frequency also increases with the increase of electrical parameter and load force; The amplitude attenuation of ultrasonic vibration will become extraordinary intense even almost to stop beat when the axis force load increase to 750 N and radial force load increase to 550 N; The gradient of resonant frequency in a radial direction is more significant than that in an axial direction. Based on the results of theoretical analysis and static loading experimental, the measures to reduce amplitude attenuation and improve output stability of amplitude under resonant frequency are proposed. The results can provide theoretical guidance for a magnetostrictive transducer used in the actual spinning ultrasonic vibration processings. [ABSTRACT FROM AUTHOR]

Nomex honeycomb composites are used extensively in aerospace, automotive, and other industries due to their superior material properties. However, the tool wear during their machining can compromise the processing accuracy and the stability of the whole machining process, thus studies on the tool wear and strengthening method are urgently needed. This study presents a radial difference calculation method (RDC) to evaluate the tool wear of the disc cutter quantitatively in both conventional cutting and ultrasonic assisted cutting. The morphology of the tool wear process and its characteristics were analyzed. Two different heat treatments (salt bath quenching and vacuum quenching) were carried out to strengthen the tool performance. The research results demonstrated that ultrasonic vibration could significantly reduce the tool wear of the disc cutter, by up to 36%, after the same machining time. Salt bath quenching and vacuum quenching can both strengthen the tool performance. Particularly, after vacuum quenching treatment, the disc cutter's metallographic grains were refined, and the tool wear could be reduced by 64%, compared to the as-received disc cutter. The findings in this study could be instructive to obtain further understanding of the machining mechanism and to improve methods in ultrasonic assisted cutting of Nomex honeycomb composites. [ABSTRACT FROM AUTHOR]

A non-contact ultrasonic abrasive machining approach provides a potential solution to overcome the challenges of machining efficiency in the high-precision polishing of optical components. Accurately modeling the material removal distribution (removal function (RF)) and surface morphology is very important in establishing this new computer-controlled deterministic polishing technique. However, it is a challenging task due to the absence of an in-depth understanding of the evolution mechanism of the material removal distribution and the knowledge of the evolution law of the microscopic surface morphology under the complex action of ultrasonic polishing while submerged in liquid. In this study, the formation of the RF and the surface morphology were modeled by investigating the cavitation density distribution and conducting experiments. The research results showed that the material removal caused by cavitation bubble explosions was uniformly distributed across the entire working surface and had a 0.25 mm edge influence range. The flow scour removal was mainly concentrated in the high-velocity flow zone around the machining area. The roughness of the machined surface increased linearly with an increase in the amplitude and gap. Increasing the particle concentration significantly improved the material removal rate, and the generated surface exhibited better removal uniformity and lower surface roughness. [ABSTRACT FROM AUTHOR]

This article reports the improvement of the adhesion of the electroless seed layer deposited on glass substrates used in creating through-glass vias (TGV) by localized surface roughening. Four glass substrates having varying roughness characteristics were prepared by electrochemical discharge machining (ECDM) and ultrasonic machining (USM). The electroless nickel seed layer was deposited directly on glass without any adhesion layer, followed by electrodeposited copper layers. In-depth surface topography and morphology analysis reveal the mechanism behind the improved adhesion during standard peel and cross-hatch adhesion tests, which were used to determine the interlayer adhesion. Localized roughening techniques generated specific microfeatures, i.e., microgrooves (in USM) or ridges (in ECDM), increasing the surface area. These features acted as interlocking/nucleation sites to hold the electroless nickel atoms, resulting in higher interfacial adhesion. USM-roughened samples exhibited stronger interfacial adhesion than their ECDM-roughened counterparts, which indicated that the interlayer adhesion depends on topography and the roughened surface's morphology. The surface with negative skewness and positive excess kurtosis promotes mechanical interlocking, offering a promising strategy for enhancing interlayer adhesion. Finally, conformal deposition in a 6 × 6 array of through-holes having an aspect ratio of ∼4 was also demonstrated. • Localized roughening of glass by USM and ECDM is demonstrated for improving adhesion of electroless deposited film. • Adhesion strength depends on the topography and morphology of the roughened surface. • USM roughening renders better adhesion than ECDM due to mechanical interlocking in the microgrooves. [ABSTRACT FROM AUTHOR]

The present study employs a two-dimensional ultrasonic surface burnishing process (2D-USBP) to enhance the surface properties of aluminum alloy. A multi-ball surface burnishing tool, operating under the synergistic effects of ultrasonic vibration and machining pressure, induces a high strain rate of plastic deformation on the aluminum alloy surface. The deformation-induced heat and convective heat transfer from the lubricant achieve a dynamic equilibrium around 90 °C, facilitating quasi-isothermal processing conditions. Microstructural characterization of the machined specimens uses electron backscatter diffraction and transmission electron microscopy. Additionally, a microhardness tester and micro-measurement in-situ mechanical testing system are employed to evaluate the mechanical properties of the surface layer before and after machining. Lubricated wear tests are performed to compare the wear resistance of the original and machined specimens. The test results indicate that the 2D-USBP generates a gradient nanostructure approximately 660 μm thick on the specimen surface, with dislocation density exhibiting a high-low-high distribution pattern along the depth. The surface hardness of the machined specimens reached approximately 120 HV, 1.6 times that of the original specimens, with the hardened layer extending to a depth of approximately 800 μm. The machined specimens demonstrated higher yield strength, fracture strength, and elongation under high strain rates. Wear test results revealed that the wear scar area of the machined specimens is only 50 % of the original specimens, significantly enhancing wear resistance. • 2D-USBP creates an 800 μm thick gradient nanostructure on the aluminum alloy. • The dislocation density exhibits a low-high-low characteristic along the depth. • The gradient nanostructure has superior strength and toughness at high strain rates. [ABSTRACT FROM AUTHOR]

• A 3DOF ultrasonic vibration tool holder was proposed for rotary ultrasonic machining. • Proposed tool holder achieve 1DOF, 2DOF and 3DOF vibration machining. • Structural optimization achieve multi-vibration integration and switching, high rotary speed practicality. • Machining effects of various vibration forms were compared. • Vibration mode affect the machining quality and tool life in grinding. • 2DOF elliptic vibration has better comprehensive machining performance. The vibration form of the tool has a significant impact on the machining effect in rotary ultrasonic machining. Compared with 1DOF rotary ultrasonic machining, multi-DOF rotary ultrasonic machining have comprehensive advantages in the machining performance. However, the current multi-DOF rotary ultrasonic machining faces the challenges of miniaturization, multi-DOF vibration integration and high rotary speed. Therefore, a 3DOF ultrasonic vibration tool holder with decoupled three-channel contactless energy transfer was proposed, which realize 1DOF, 2DOF and 3DOF rotary ultrasonic machining with the same resonant frequency and the vibration conversion functions at high rotation speed. Structure design, principle analysis and simulation verification was carried out to determine the structure size and material. Through manufacturing and testing of prototype, the results show that under the performance of high speed, high transfer efficiency with 93 % and low temperature rise. The prototype of 3DOF ultrasonic vibration tool holder can not only integrate six vibration forms with high amplitude, but also has the function of replacing the milling tool for metal and grinding tool for brittle materials. Finally, through machining experiments with different vibration forms, two kinds of elliptical vibration produce regular textures with different shapes in the Ti-6Al-4V milling. In Al2O3 grinding, the surface roughness is the lowest under 2DOF vertical elliptical vibration grinding. While the 2DOF horizontal elliptical vibration grinding significantly improves the chip removal and prolongs the tool life. These findings provide guidance for machining performance under various vibration mode. It was proved that this tool holder integrated and switch with multiple vibration modes is of great value for high efficiency and high-quality multi-procedure machining. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A high-order bilateral matching network for high-frequency piezoelectric rotary ultrasonic machining system is proposed. • The feasible region and dynamic adjustment criterion of asymmetric dynamic LCC matching parameters are designed. • High efficiency and high stability of energy conversion are achieved. The processing efficiency and machining quality of piezoelectric rotary ultrasonic machining (PRUM) system are closely related to its electromagnetic energy conversion units and electroacoustic energy conversion units. Generally, the high efficiency and high-power capacity of PRUM systems are limited by several energy conversion devices including the capacitive piezoelectric transducer (PT) load, loosely coupled rotating transformer (RT), and non-soft switching inverter. This article improves the overall performance of high-frequency PRUM system by bilateral matching network. On the rotating side, the compared results of five different static matching schemes show that the CS matching scheme ensures stable and efficient vibration of capacitive PTs even under incomplete matching. On the stationary side, a dynamic LCC matching scheme is adopted to keep the output impedance angle of H-bridge inverter in the weak inductive state. Finally, the proposed high-order matching network in this article makes the efficiency of high-frequency PRUM system over 90 % steadily. [ABSTRACT FROM AUTHOR]

Ultrasonic technology is widely used in the field of rail defects detection. 3D reconstruction of rail defects can intuitively restore the 3D size and spatial position of the defects inside the rail. Currently, ultrasound-based 3D reconstruction requires a multi-probe or mechanical scanning platform in a laboratory setting, which is not suitable for the railway environment. In addition, 3D reconstruction requires a large amount of data, making it difficult to collect sufficient ultrasonic 3D defect data for long-distance rail inspections. This paper proposes an ultrasonic field-guided 3D reconstruction method combined with machine learning hybrid physics for rail defects. It combines both sound field GAN model to reconstruct the defect 3D model from the 2D B-scan data. The proposed method can generate a defect cross-sectional image using a deep learning algorithm guided by the acoustic field in the B-scan space, and extract the 3D size information of the defect from the 2D B-scan information by establish a defect echo model. By stablishing a spatial mapping relationship between the B-scan and the rail coordinate system, the position of the defect in the rail coordinate system is obtained. The defect data of standard damage rails are tested. Experiment results indicate that the defects in different parts of the rail can be reconstructed by the proposed method. The average size error rate is 9.56%–21.14 %, and the average height error is 3.458mm–6.353 mm. [ABSTRACT FROM AUTHOR]

A prediction model based on XGBoost is proposed for ultrasonic degradation of micropollutants' kinetic constants. After parameter optimization through iteration, the model achieves Evaluation metrics with R2 and SMAPE reaching 0.99 and 2.06%, respectively. The impact of design parameters on predicting kinetic constants for ultrasound degradation of trace pollutants was assessed using Shapley additive explanations (SHAP). Results indicate that power density and frequency significantly impact the predictive performance. The database was sorted based on power density and frequency values. Subsequently, 800 raw data were split into small databases of 200 each. After confirming that reducing the database size doesn't affect prediction accuracy, ultrasound degradation experiments were conducted for five pollutants, yielding experimental data. A small database with experimental conditions within the numerical range was selected. Data meeting both feature conditions were filtered, resulting in an optimized 60-data group. After incorporating experimental data, a model was trained for prediction. Degradation kinetic constants for experiments (k E) were compared with predicted constants (for 800 data-based model: k P -800 and for 60 data-based model: k P -60). Results showed ibuprofen, bisphenol A, carbamazepine, and 17β-Estradiol performed better on the 60-data group (k P -60/k E : 1.00, 0.99, 1.00, 1.00), while caffeine suited the model trained on the 800-data group (k P -800/k E : 1.02). [Display omitted] • Database of kinetic constants of micro pollutants degradation by ultrasound. • Comparative analysis of US degradation kinetic constant prediction using ML and MLR models. • Validate ML models with experimental data. [ABSTRACT FROM AUTHOR]

This brief proposes a field programmable gate array (FPGA) based real‐time inference machine for A‐mode ultrasonic echo pattern recognition. The proposed scheme can aid a probe positioning of single‐transducer based ultrasound devices by detecting specific echo patterns on a scanline. The inference machine is based on a combination of a support vector machine and a finite state machine. The proposed inference machine utilizes a minimal pre‐processing for a feature extraction, considering a nature of distinctive echo patterns. In addition, a primary computation of linear support vector machine is performed sequentially, and the finite state machine for robust binary classification is relatively compact. As a result, the overall structure of the inference machine can be concisely implemented on FPGA. The proposed inference machine was assembled with a customized A‐mode ultrasound scanner. The maximum utilization percentage of look‐up‐tables in FPGA was less than 1.5%. In evaluation of inferences, the resultant sensitivity and the specificity were 96.2% and 99.87%, respectively. [ABSTRACT FROM AUTHOR]

This study investigated the applicability of using ultrasonic wave signals in detecting early fire damage in concrete. This study analyzed the reliability of using the linear (wave velocity) and nonlinear (coherence) parameters from ultrasonic pulse measurements and the applicability of machine learning in assessing the thermal damage of concrete cylinders. While machine learning has been used in some damage detections for concrete, its feasibility has not been fully investigated in classifying thermal damage. Data was collected from laboratory experiments using concrete specimens with three different water-to-binder ratios (0.54, 0.46, and 0.35). The specimens were subjected to different target temperatures (100 °C, 200 °C, 300 °C, 400 °C, and 600 °C) and another set of cylinders was subjected to room temperature (20 °C) to represent the normal temperature condition. It was observed that P-wave velocities increased by 0.1% to 10.44% when the concretes were heated to 100 °C, and then decreased continuously until 600 °C by 48.46% to 65.80%. Conversely, coherence showed a significant decrease after exposure to 100 °C but had fluctuating values in the range of 0.110 to 0.223 thereafter. In terms of classifying the thermal damage of concrete, machine learning yielded an accuracy of 76.0% while the use of P-wave velocity and coherence yielded accuracies of 30.26% and 32.31%, respectively. [ABSTRACT FROM AUTHOR]

This research focuses on the load characteristics of piezoelectric transducers in the process of longitudinal vibration ultrasonic welding. We are primarily interested in the impedance characteristics of the piezoelectric transducer during loading, which is studied by leveraging the equivalent circuit theory of piezoelectric transducers. Specifically, we propose a cross-value mapping method. This method can well map the load change in ultrasonic welding to the impedance change, aiming to obtain an equivalent model of impedance and load. The least-squares strategy is used for parameter identification during data fitting. Extensive simulations and physical experiments are conducted to verify the proposed model. As a result, we can empirically find that the result from our model agrees with the impedance characteristics from the real-life data measured by the impedance meter, indicating its potential for real practice in controller research and transducer design. [ABSTRACT FROM AUTHOR]

The paper presents the fixtures with movably mounted turning and drilling cutting tools. The fixtures were developed on the principle of oscillating tooltip similar to the principle of the ultrasonic vibration-assisted machining process. However, presented fixtures do not need an electricity source and utilize mainly forced and self-excited oscillations. In general, the tool vibrations during the cutting process are recognized as a negative phenomenon as it causes a shortening of the tool life and worsens the roughness of the machined surfaces. However, a deeper understanding of the cutting process proposes possible positive effects of tool vibration in terms of chip shapes, flank wear, chip volume coefficient, and quality of the machined surface. Experimentally obtained dependence of mentioned quantities is provided in the paper. [ABSTRACT FROM AUTHOR]

In the process of ultrasonic vibration cutting (UVC), the acoustic performance parameters of ultrasonic machining system change because of systems heating up and cutting loads. The changes of acoustic performance parameters will affect resonant frequency, impedance, and power match of the ultrasonic machining system, and stability of the amplitude of UVC system. It is hard to monitor the acoustic performance parameters online. Based on the analysis of the correlation mechanism between transducer temperature and acoustic performance parameters, the correlation models between transducer temperature and resonance frequency, static capacitance, and dynamic resistance of ultrasonic vibration machining system are established by curve regression analysis modeling method. The acoustic performance parameters of an ultrasonic vibration machining system are determined by transducer temperature using the correlation models. The effectiveness of the model is verified by experiments. It gives the information for the stability evaluation of the ultrasonic vibration machining process, the dynamic impedance matching of the ultrasonic machining system, and the power matching adjustment of the ultrasonic power supply. [ABSTRACT FROM AUTHOR]

The core of the ultrasonic machining system is the acoustic vibration component. Due to the inconsistency of the assembly conditions between the junction surfaces of the acoustic vibration component, the resonant frequency of the ultrasonic acoustic vibration component after the size adjustment of the ultrasonic horn is low, and the Impedance mismatch occurs in the ultrasonic system. In this paper, considering the influence of assembly conditions, the optimal assembly parameters were studied to reduce the junction surface's influence on the ultra-sonic horn's performance parameters. The paper analyzed the assembly structure, assembly parameters, and static and dynamic performance parameters of the acoustic vibration components and established a static and dynamic performance parameter measurement system. The assembly parameters of the ultrasonic acoustic vibration components were analyzed and determined. The static performance parameters of the ultrasonic acoustic components were measured and analyzed for the assembly parameters of the junction surface at the ultrasonic horn and the straight-edged knife. The optimal assembly parameters were preliminarily determined based on the analysis of the static performance parameters. The optimal assembly parameters of the junction surface of the ultrasonic horn and the straight-edged knife were determined through the measurement and analysis of the dynamic performance parameters of the two junction surfaces. The work is the basis for the adjustment of the ultrasonic horn. It also provides a basis for improving the working performance, manufacturing precision, and production efficiency of the ultrasonic horn while further popularizing the application of ultrasonic processing. [ABSTRACT FROM AUTHOR]

Zirconia (ZrO 2) ceramics, as advanced structural ceramics, are gradually used in manufacturing, aerospace and other fields due to their excellent properties. However, it is problematic to process the ZrO 2 ceramics by conventional machining. This study adopted the longitudinal-torsional coupled rotary ultrasonic machining to process the ZrO 2 ceramics. Firstly, the material removal mechanism was clarified in the view of a single abrasive particle. Then, the longitudinal-torsional coupled rotary ultrasonic machining experiment was conducted to explore the effect of processing parameters on the cutting force, hole surface roughness, surface morphology, and single abrasive particle wear with those in the conventional machining. It was found that the cutting force reduced with the spindle speed and ultrasonic power, growing with the feed rate. The hole surface roughness declined with spindle speed, enhanced with feed rate, and decreased first and then increased with ultrasonic power. Compared with the conventional machining, both the cutting force and surface roughness were significantly reduced in the longitudinal-torsional coupled rotary ultrasonic machining. The test results proved that the hole surface quality was improved, and the single abrasive particle wear was reduced in the longitudinal-torsional coupled rotary ultrasonic machining. This study's results are considered instrumental in the longitudinal-torsional coupled rotary ultrasonic machining processing of hard and brittle materials. [ABSTRACT FROM AUTHOR]

The welding of foils, textiles, and textile composites made of thermoplastic polymer materials using machines with an ultrasonic rotary sonotrode is a high-tech welding technique. Many authors have dealt with only a few parameters in earlier papers, mainly mentioning the speed, i.e., the welding time, and the power of the ultrasonic generator. In this paper, the acoustic model of ultrasonic welding is defined. Based on the model, a group of 44 different parameters important for ultrasonic welding of polymer materials has been summarised, namely 12 parameters of the polymer material, 11 general acoustic and electroacoustic parameters, and 21 technical parameters depending on the ultrasonic machine. Based on this, a comprehensive mathematical derivation was carried out, linking parameter groups with other findings from acoustics, thermodynamics of polymers, and technical and technological parameters of welding polymer materials. The most important parameters are the power of the ultrasonic generator and the welding time, which in practice are adjusted to produce a solid weld. The method of measuring the amplitude of the sonotrode using a photonic sensor is presented in this paper. For 42 groups of welds done at various welding speeds and ultrasonic generator powers, the breaking forces of ultrasonic welds were measured. There are illustrations of power dependence and breaking forces. The accuracy of the mathematical model was confirmed by comparison with the calculation results based on the findings of these measurements. [ABSTRACT FROM AUTHOR]

The traditional machining process is not suitable for machine brittle material like glass, ceramics and hard alloys. To machine such kinds of materials, the non-traditional machining process is used. In today's modern industry, ultrasonic machining is used for machine hard and brittle materials. Operation conditions of USM very high frequency (18 to 46 kHz) and tool vibration gives around 6-μm amplitude. Cutting tools have an amplitude of around 5–90 μm for achieving good machining quality. In the USM process, horn transfers the vibration force from the transducer to the cutting tool end. Novel horn design gives the magnification factor (MF) for vibration amplitude. In this paper, the horn is invented for the USM process with the help of ANSYS and finite element analysis (FEA) to manage the necessary performance for the industry. First of all, the horn profile is designed by using the differential equations for getting a 3D model. The shape of mode and frequencies is found out by modal analysis performance. Similarly, design feasibility is verified by balanced retaliation performance analysis to found out the magnification factor with the help of a novel horn. Finally, the design of the novel horn is compared with the suggestive horn. [ABSTRACT FROM AUTHOR]

This paper is focused on the issue of preparing the cutting edge microgeometry of cutting inserts made of cubic boron nitride (CBN). The aim of this research was to investigate the possibilities of rotary ultrasonic machining (RUM) for preparing asymmetric cutting edge microgeometries of various shapes (chamfers, circular, and elliptical rounding and their combinations) on a CBN cutting tool. In this article, a new type of advanced cutting edge preparation method is presented. CBN is relatively resistant to the most often used (abrasive) methods of cutting-edge preparation, due to its very high hardness (which is a prerequisite property for machining difficult-to-cut materials). Such hard materials could be processed using advanced manufacturing methods, and rotary ultrasonic machining (RUM) is one such method. Experiments have shown that RUM can be used for machining CBN. However, high hardness is not the only challenge here. For cutting edge preparation, it is necessary to achieve an adequate accuracy of size and dimensions. The presented paper analyzes the suitability of the RUM process for processing CBN inserts. The results of the experiment showed that this method can be used for preparing asymmetric cutting edge microgeometries with various shapes. [ABSTRACT FROM AUTHOR]

In this article, the effect of optimal selection of vibration and cutting parameters on cutting forces in the machining process with ultrasonic vibration assistance has been investigated and the results have been compared in two modes of conventional machining and of ultrasonic vibration assisted machining. In the investigation of the effect of ultrasonic vibration assistance on the machining process, analyzes have been carried out in different cutting speeds, and the effect of changing the cutting speed in relation to the tool's oscillation speed has been investigated. Finite element modeling and simulation has been done with DEFORM finite element software. The results show that the application of ultrasonic vibration in the machining process leads to the reduction of tangential and axial cutting and the reduction of heat resulting from the cutting process. By examining the results, it was found that in the machining process with ultrasonic vibration assistance, when the cutting speed is at least 30% lower than the vibration speed of the tool tip, the process has a favorable efficiency, and the favorable effects of applying ultrasonic vibration on the process include reducing shear forces, reducing the heat generated From cutting, reducing the friction coefficient between the tool and the workpiece, helping to improve the chip flow, etc. [ABSTRACT FROM AUTHOR]

Ultrasonic machining is a new technique, and one of the new and promising processes for machining metals, especially metal alloys with low machinability. In this paper, a set of laboratory studies is used to investigate the effect of using ultrasonic vibrations on the force required for drilling of the thin aluminum workpieces. For this perpuse, three aluminum workpieces with different thicknesses are drilled under three different rotation speeds, and four different advance rates. The results showed that in two aluminum workpieces, 1 and 1.5 mm, the use of ultrasonic vibrations generally reduced the axial force, but in the 2 mm workpiece, it is not possible to understand a meaningfull effect of adding ultrasonic vibrations. In other words, it can be said that adding ultrasonic vibrations with constant amplitude and frequency does not have the same effect on drilling in different conditions, and to reach the most efficient drilling, the characteristics of optimal vibration should be studied. [ABSTRACT FROM AUTHOR]

A study on ultrasonic vibration-assisted electrical discharge machining (UVEDM) micro-hole, which mainly includes three key designs, was conducted to improve the machining performance of the electric discharge machining (EDM) micro-holes on TC4 titanium alloy. First, a mathematical model for the velocity of the flow field in the interelectrode gap was established. Consequently, the effect of the presence or absence of ultrasonic vibration on the flow velocity was analyzed. Furthermore, based on COMSOL Multiphysics, the two distributions of the flow field and the debris in the interelectrode gap were simulated, and the influence of ultrasonic amplitude on them was analyzed. Finally, the study of UVEDM micro-hole machining with different ultrasonic amplitudes was conducted. The machining performance of the UVEDM micro-hole was found to increase with the increment of the ultrasonic amplitude and the optimal value of 5.22 μm, while the performance decreases when the ultrasonic amplitude goes beyond the optimal value. Compared with EDM micro-hole, the MMR is increased by 2.4 times, and the electrode loss and hole taper are reduced by 56% and 24%, respectively. [ABSTRACT FROM AUTHOR]

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Ultrasonic machining is an advanced machining process which is applied for the machining of tough and fragile materials viz. glass, ceramics, etc. The ultrasonic horn is a most essential component used to transfer the longitudinal mode of vibration to the ultrasonic tool through a transducer. This investigation has considered the design of two different profiles of ultrasonic horns (cylindrical & stepped) using tungsten carbide material in dynamic conditions. Modal analysis is performed to calculate the mode shapes and natural frequencies of both the horn profiles. The dimension of the horns under the frequency of 20 kHz is considered. The analysis is performed using ANSYS 18.1 workbench interface. Harmonic response analysis is executed to compute the stress and deformation behaviour of both the horn profiles. After the stresses are generated, a defect is introduced at the maximum stress point in both the horn design. The defects are generated in three different orientations, viz. along the longitudinal axis, perpendicular axis, and another one is inclined with respect to the oscillation of the horn. The maximum stress is generated in the stepped horn that is 370.55 MPa, where the defect is located at perpendicular to the longitudinal axis with respect to the oscillation of the horn. The current analysis can be considered as the tool to understand the behaviour of the horn in the presence of a defect in ultrasonic machining. [ABSTRACT FROM AUTHOR]

To address the phenomenon that ultrasonic-assisted machining might improve the microstructural properties of high-strength aluminum alloy surfaces by forming micro-scoring surfaces on the workpiece surfaces, an experimental study on the microstructure of surfaces milled by single- excitation rotary ultrasonic longitudinal torsion composite milling was conducted: the effects of machining parameters on the water contact angle were analyzed based on the water contact angle theory and the kinematic theory of longitudinal torsion milling; secondly, a single-excitation ultrasonic longitudinal torsion milling test platform was built, and the orthogonal method was used to study the effects of different machining parameters on the surface roughness, milling forces and surface wetting performances. The results show that the surface quality is best when the ultrasonic amplitude is as 4 µm, and the cutting speed and feed are positively correlated with the surface roughness and water contact angle; the surface water contact angle under ultrasonic machining mode is larger than that of the normal mode, and the surface water contact angle machined by low amplitude is larger than that of high amplitude during ultrasonic machining. And the differences between the surface water contact angle machined by high amplitude and low amplitude are not significant when the speed reaches a certain amount. Suitable machining parameters under the ultrasonic longitudinal revise processing method may reduce the roughness of the machined surfaces and change the wettability of the surfaces. [ABSTRACT FROM AUTHOR]

As a new method developed for machining difficult-to-cut materials, ultrasonic vibration–assisted machining technology not only could be effective in reducing cutting force and temperature but also could be significant in obtaining residual compressive stress. Especially, residual compressive stress is essential to realize anti-fatigue manufacturing for components. However, in recent years, research on residual stresses of ultrasonic vibration–assisted machining mainly focuses on experimental and finite element analysis methods. In this paper, an analytical model was established by considering the effect of ultrasonic vibration to predict residual stresses and reveal the mechanism for UVM of in situ TiB2/Al-MMCs. And a series of experiments were conducted to verify the residual stress model proposed and analyze the effect of ultrasonic vibration and cutting parameters on the surface residual stress. The results show that the predicted residual stresses are in good agreement with measured residual stress. Cutting parameters have a significant effect on the surface residual stress by influencing cutting force and cutting temperature. Residual compressive stresses could be achieved in both UVM and conventional milling, and residual compressive stresses in the former are larger than that in the latter. With cutting speed and cutting depth increasing, the relative increase ratio between UVM, and CM decreased gradually, while with feed rate increasing, it increased first and then decreased slightly. [ABSTRACT FROM AUTHOR]

Objective To investigate the effects of different ultrasonic machines on the performance of radiomics models using ultrasound (US) images in the prediction of lymph node metastasis (LNM) for patients with cervical cancer (CC) preoperatively. Methods A total of 536 CC patients with confirmed histological characteristics and lymph node status after radical hysterectomy and pelvic lymphadenectomy were enrolled. Radiomics features were extracted and selected with US images acquired with ATL HDI5000, Voluson E8, MyLab classC, ACUSON S2000, and HI VISION Preirus to build radiomics models for LNM prediction using support vector machine (SVM) and logistic regression, respectively. Results There were 148 patients (training vs validation: 102:46) scanned in machine HDI5000, 75 patients (53:22) in machine Voluson E8, 100 patients (69:31) in machine MyLab classC, 110 patients (76:34) in machine ACUSON S2000, and 103 patients (73:30) in machine HI VISION Preirus, respectively. Few radiomics features were reproducible among different machines. The area under the curves (AUCs) ranged from 0.75 to 0.86, 0.73 to 0.86 in the training cohorts, and from 0.71 to 0.82, 0.70 to 0.80 in the validation cohorts for SVM and logistic regression models, respectively. The highest difference in AUCs for different machines reaches 17.8% and 15.5% in the training and validation cohorts, respectively. Conclusions The performance of radiomics model is dependent on the type of scanner. The problem of scanner dependency on radiomics features should be considered, and their effects should be minimized in future studies for US images. [ABSTRACT FROM AUTHOR]

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rotary ultrasonic machining is a cost-effective and precise machining method for hard and brittle materials. Aiming at processing SiCp/Al composites, a rotary ultrasonic grinding spindle is proposed in the present study. Expressions were established to calculate the displacement, rotation angle, bending moment, and shear force of the vibrating elements based on the Mindlin moderately thick plate theory. Combining continuous and boundary conditions of vibrating elements with the proposed expressions, the vibration model and frequency equation of a longitudinal-flexural resonating transformer with a large load were established. Then two transformers were designed according to the frequency equation. The resonant characteristics of the transformers were studied using finite element analysis, impedance analysis, and ultrasonic resonance experiments. The obtained results show that the maximum deviation between the resonant frequency and the design frequency of the transformers was 4.95%. Moreover, the maximum deviation of the positions of the pitch circles was 6.51%. It is concluded that the proposed designs have high accuracy. Finally, the orthogonal single-factor experiments of SiCp/Al composites were performed with and without ultrasound. The obtained results show that introducing ultrasonic vibrations significantly reduces the grinding force and the surface roughness while improving the surface quality of the SiCp/Al workpiece. The present study is expected to provide experimental fundamentals to further improve the structure of the grinding spindle, optimize process variables of ultrasound-assisted grinding, and improve the processing efficiency. [ABSTRACT FROM AUTHOR]

This study was carried out to determine different forms of the effectiveness of oxalic and formic acid applied against Varroa destructor parasite, which is seen as the main cause of colony losses and low yield in honeybees (Apis mellifera L.) worldwide. Formic acid was tested in two trial groups (FormicProTM; 70% liquid formic acid) and oxalic acid in six trial groups (Dribbling; Spray; Sublimation; Glycerine Shop towel; sunflower Oil Shop Towel; Ultrasonic Fogging). The control group was not exposed to the application during the study. According to the results, the highest effect against varroa was determined in the FormicProTM group (P<0.001). However, incubation activity of colonies almost completely ceases in formic acid groups. The rate of varroa infestation increased control group and the oxalic acid group treated with an ultrasonic fogging machine (P<0.001). In the autumn, it was concluded that not every application provided effective control against varroa at the location where the study was conducted. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced polymer (CFRP) is prone to surface damage such as delamination, uncut fibers and tear during the process of hole-making in aerospace field. Helical milling greatly improves the exit damage of CFRP holes, but the entrance damage will further deteriorate. To further diminish hole entrance damage and enhance hole machining quality, this paper proposed a longitudinal torsional ultrasonic assisted helical milling method to investigate the formation mechanism of hole entrance damage based on a cutting fracture mechanism with a fiber angle of 0° to 180°. The differences of hole entrance damage between longitudinal torsional ultrasonic helical milling (LTUHM) and traditional helical milling (THM) were analysed by a series of comparative experiments. The results showed that longitudinal torsional ultrasonic machining significantly reduced the damage of CFRP holes compared to THM. The delamination damage factor and uncut fibers factor of the hole entrance are reduced to 24.92% and 20.28%, respectively, and the fiber fracture surface is flatter under LTUHM. The study provides a production guide for efficient hole-making of CFRP. [ABSTRACT FROM AUTHOR]

In the current paper, the effect of tool wear for a constant period of time (360 s) during conventional and ultrasonic assisted machining of Inconel 718 is investigated in terms of cutting forces, temperature, and deviation measurements. For fixed process parameters turning experiments have been performed with and without the application of tangential vibration. Ultrasonic assisted turning (UAT) experiments have been compared with conventional turning (CT). The experimental results reveal that cutting forces and temperature increase linearly in the case of UAT whereas remaining constant in CT for a constant period of time. Besides the tool wear rate in the case of UAT is more than that in the CT. [ABSTRACT FROM AUTHOR]

SiCp/Al composites are a kind of particle-reinforced composite material, which has been widely used in various fields due to its excellent performance. However, during the machining, the damage and failure of the SiC particles, the aluminum matrix, and the interface phase will cause many surface and edge defects. These defects will seriously affect the application of SiCp/Al composites. In this paper, a finite element model of randomly distributed multi-cell SiCp/Al composites with longitudinal-torsional ultrasonic vibration-assisted milling was established to analyze the formation mechanism of edge defects of the material. The simulation results showed that the main reason for the formation of edge defects was that the interface, SiC particles, and the Al matrix will produce cracks during machining, and these cracks will propagate and cause particle breakage, matrix tearing, and edge gaps. According to different machined parameters, the ultrasonic vibration-assisted milling experiment was carried out. The test results showed that the actual processed workpiece does have defects such as edge gaps. The depth of cut and the feed per tooth had a serious influence on the edge defect value, while the cutting speed had a small effect. Moreover, under the condition of applying appropriate ultrasonic amplitude, the phenomenon of edge defects and the surface quality were significantly improved. Therefore, the application of ultrasonic vibration-assisted milling can improve the surface and edge quality of SiCp/Al composites. [ABSTRACT FROM AUTHOR]