Pub Date : 2026-01-25DOI: 10.1016/j.ultras.2026.107974
Md Tausif Akram , Pinaki Mazumder , Kyungjun Song
Recent advancements in acoustic metasurfaces have significantly improved beamforming and steering capabilities, with beam multiplexing emerging as a key enabler of multidirectional sound projection. This paper proposes a cylindrical holographic acoustic metasurface integrated with surface wave reflectors (SWRs) to realize efficient acoustic beam multiplexing. By transitioning from conventional planar designs to a cylindrical geometry, the proposed metasurface supports the simultaneous generation of multiple highly directional beams at distinct combinations of elevation and azimuthal angles. The integration with SWRs enhances beam collimation and suppresses side lobes, thereby ensuring high directivity and acoustic field confinement. Both simulations and experimental validations confirmed that the metasurface could steer multiple beams generated by a single monopole source in specific directions in 3D space; this capability can help ensure reliable performance across various applications such as sonar, medical imaging, and acoustic communication. The proposed approach represents a versatile and scalable conformal platform for spatially multiplexed acoustic beam steering, marking a significant advancement in the development of multifunctional acoustic metasurfaces.
{"title":"Directional beam multiplexing using cylindrical holographic acoustic metasurfaces integrated with surface wave reflectors","authors":"Md Tausif Akram , Pinaki Mazumder , Kyungjun Song","doi":"10.1016/j.ultras.2026.107974","DOIUrl":"10.1016/j.ultras.2026.107974","url":null,"abstract":"<div><div>Recent advancements in acoustic metasurfaces have significantly improved beamforming and steering capabilities, with beam multiplexing emerging as a key enabler of multidirectional sound projection. This paper proposes a cylindrical holographic acoustic metasurface integrated with surface wave reflectors (SWRs) to realize efficient acoustic beam multiplexing. By transitioning from conventional planar designs to a cylindrical geometry, the proposed metasurface supports the simultaneous generation of multiple highly directional beams at distinct combinations of elevation and azimuthal angles. The integration with SWRs enhances beam collimation and suppresses side lobes, thereby ensuring high directivity and acoustic field confinement. Both simulations and experimental validations confirmed that the metasurface could steer multiple beams generated by a single monopole source in specific directions in 3D space; this capability can help ensure reliable performance across various applications such as sonar, medical imaging, and acoustic communication. The proposed approach represents a versatile and scalable conformal platform for spatially multiplexed acoustic beam steering, marking a significant advancement in the development of multifunctional acoustic metasurfaces.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"162 ","pages":"Article 107974"},"PeriodicalIF":4.1,"publicationDate":"2026-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-24DOI: 10.1016/j.ultras.2026.107975
Mohammed Elaouni , Noura Ezzahni , Soufyane Khattou , Madiha Amrani , Afaf Bouzidi , Abdellatif Gueddida , El Houssaine El Boudouti , Bahram Djafari-Rouhani
Topological materials have attracted significant attention due to their distinct edge states, known for their robustness to local perturbations. In the field of phononic crystals, these states manifest as topological surface or interface modes, offering promising applications in waveguiding and energy harvesting. This study explores the emergence and control of azimuthal symmetric torsional interface states in phononic nanowires (PNWs) composed of alternating cylindrical layers. In the framework of the Su–Schrieffer–Heeger (SSH) model, we use the Green’s function approach to derive analytical expressions of the dispersion relations to predict all Dirac-point positions and interface modes. The analytical results are confirmed by finite element method simulations performed using COMSOL Multiphysics. In PNWs with symmetric unit cells, band-structures and scattering calculations reveal tunable interface modes whose frequencies and propagation characteristics can be adjusted via geometrical parameters. We also demonstrate through Zak-phase, local density of states (LDOS), and transmission-spectrum analyses that these interface states remain fixed and topologically protected under variations of the dimerization parameter. These findings pave the way for exploiting topological interface states in PNWs, thus opening to innovative phononic devices and contributing to the advancement of the field of topological physics.
{"title":"Dirac cones and topological torsional modes in phononic nanowires using Su–Schrieffer–Heeger Model","authors":"Mohammed Elaouni , Noura Ezzahni , Soufyane Khattou , Madiha Amrani , Afaf Bouzidi , Abdellatif Gueddida , El Houssaine El Boudouti , Bahram Djafari-Rouhani","doi":"10.1016/j.ultras.2026.107975","DOIUrl":"10.1016/j.ultras.2026.107975","url":null,"abstract":"<div><div>Topological materials have attracted significant attention due to their distinct edge states, known for their robustness to local perturbations. In the field of phononic crystals, these states manifest as topological surface or interface modes, offering promising applications in waveguiding and energy harvesting. This study explores the emergence and control of azimuthal symmetric torsional interface states in phononic nanowires (PNWs) composed of alternating cylindrical layers. In the framework of the Su–Schrieffer–Heeger (SSH) model, we use the Green’s function approach to derive analytical expressions of the dispersion relations to predict all Dirac-point positions and interface modes. The analytical results are confirmed by finite element method simulations performed using COMSOL Multiphysics. In PNWs with symmetric unit cells, band-structures and scattering calculations reveal tunable interface modes whose frequencies and propagation characteristics can be adjusted via geometrical parameters. We also demonstrate through Zak-phase, local density of states (LDOS), and transmission-spectrum analyses that these interface states remain fixed and topologically protected under variations of the dimerization parameter. These findings pave the way for exploiting topological interface states in PNWs, thus opening to innovative phononic devices and contributing to the advancement of the field of topological physics.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"162 ","pages":"Article 107975"},"PeriodicalIF":4.1,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-23DOI: 10.1016/j.ultras.2026.107973
Jan Horňas, Ondřej Vích, Lenka Šedková, Ivan Mlch, Bohuslav Cabrnoch, Michal Král
Reliable Lamb-wave–based Structural Health Monitoring (SHM) depends on accurate baseline selection under varying temperatures. This study presents LambNet-T, a lightweight path-conditional Transformer-based autoencoder for temperature-aware baseline learning across multiple transducer paths. LambNet-T employs Attention Pooling (AP) to generate contextual embeddings and enables robust baseline selection using Cosine Similarity (CS) with a Median-based evaluation strategy, improving diagnostic accuracy and temperature robustness in multi-path Lamb-wave SHM. Experiments on a composite panel over −10 to +50 °C used only four baseline temperatures to reflect practical constraints, with quadratic interpolation for data augmentation. LambNet-T demonstrated significantly higher training efficiency than a convolutional autoencoder (CAE-GAP). During inference, the Median of the highest path-specific CS values identified the optimal temperature-compensated baseline. The method achieved high precision (R2 = 0.994 ± 0.001), outperforming both CAE-GAP and conventional Optimal Baseline Selection (OBS). Integration with an existing damage localization framework reduced impact location errors to as low as 4.12 mm. A conservative statistical filter, based on baseline selection variability, was applied to manage uncertainty. All experimental datasets are openly available for reproducibility.
{"title":"LambNet-T: A lightweight path-conditional transformer autoencoder for temperature-aware baseline learning in Lamb-wave SHM","authors":"Jan Horňas, Ondřej Vích, Lenka Šedková, Ivan Mlch, Bohuslav Cabrnoch, Michal Král","doi":"10.1016/j.ultras.2026.107973","DOIUrl":"10.1016/j.ultras.2026.107973","url":null,"abstract":"<div><div>Reliable Lamb-wave–based Structural Health Monitoring (SHM) depends on accurate baseline selection under varying temperatures. This study presents LambNet-T, a lightweight path-conditional Transformer-based autoencoder for temperature-aware baseline learning across multiple transducer paths. LambNet-T employs Attention Pooling (AP) to generate contextual embeddings and enables robust baseline selection using Cosine Similarity (CS) with a Median-based evaluation strategy, improving diagnostic accuracy and temperature robustness in multi-path Lamb-wave SHM. Experiments on a composite panel over −10 to +50 °C used only four baseline temperatures to reflect practical constraints, with quadratic interpolation for data augmentation. LambNet-T demonstrated significantly higher training efficiency than a convolutional autoencoder (CAE-GAP). During inference, the Median of the highest path-specific CS values identified the optimal temperature-compensated baseline. The method achieved high precision (R<sup>2</sup> = 0.994 ± 0.001), outperforming both CAE-GAP and conventional Optimal Baseline Selection (OBS). Integration with an existing damage localization framework reduced impact location errors to as low as 4.12 mm. A conservative statistical filter, based on baseline selection variability, was applied to manage uncertainty. All experimental datasets are openly available for reproducibility.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"163 ","pages":"Article 107973"},"PeriodicalIF":4.1,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146114346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-23DOI: 10.1016/j.ultras.2026.107967
Zhongtao Hu , Xudong Chen
Ultrasound vortices have rapidly expanded their applications to areas like particle trapping, contactless manipulation, acoustic communications. In ultrasonic imaging and therapy involving bone tissues, these vortex beams offer intriguing possibilities but transmitting them through bone (especially the skull) poses challenges. Traditional acoustic lenses were engineered to rectify skull-induced beam aberration, and their capacity was limited to generating only static ultrasound fields within the brain. To overcome this constraint, our study presents a novel method for transcranially steering focused ultrasound vortex using 3D printed binary acoustic metasurfaces (BAMs) with a thickness of 0.8 λ. We tackled the challenge of skull-induced phase aberration by computing the phase distribution via a time reversal technique, which concurrently enabled the generation of a steerable focused vortex inside an ex vivo human skull by adjusting the operating frequency. Both numerical and simulations experiments were conducted to validate the capabilities of BAMs. We further conducted numerical demonstrations of higher-order vortices () inside the skull using the BAM, confirming that the approach is extensible beyond the fundamental case. This development paves the way for designing cost-effective particle-trapping systems, facilitating clot manipulation, and applying acoustic-radiation forces and torques within or across bone structures, thus presenting a new frontier for potential biomedical applications.
{"title":"Transcranial steering of focused ultrasound vortex with binary acoustic metasurfaces","authors":"Zhongtao Hu , Xudong Chen","doi":"10.1016/j.ultras.2026.107967","DOIUrl":"10.1016/j.ultras.2026.107967","url":null,"abstract":"<div><div>Ultrasound vortices have rapidly expanded their applications to areas like particle trapping, contactless manipulation, acoustic communications. In ultrasonic imaging and therapy involving bone tissues, these vortex beams offer intriguing possibilities but transmitting them through bone (especially the skull) poses challenges. Traditional acoustic lenses were engineered to rectify skull-induced beam aberration, and their capacity was limited to generating only static ultrasound fields within the brain. To overcome this constraint, our study presents a novel method for transcranially steering focused ultrasound vortex using 3D printed binary acoustic metasurfaces (BAMs) with a thickness of 0.8 λ. We tackled the challenge of skull-induced phase aberration by computing the phase distribution via a time reversal technique, which concurrently enabled the generation of a steerable focused vortex inside an <em>ex vivo</em> human skull by adjusting the operating frequency. Both numerical and simulations experiments were conducted to validate the capabilities of BAMs. We further conducted numerical demonstrations of higher-order vortices (<span><math><mrow><mi>l</mi><mo>=</mo><mn>2</mn><mo>-</mo><mn>4</mn></mrow></math></span>) inside the skull using the BAM, confirming that the approach is extensible beyond the fundamental case. This development paves the way for designing cost-effective particle-trapping systems, facilitating clot manipulation, and applying acoustic-radiation forces and torques within or across bone structures, thus presenting a new frontier for potential biomedical applications.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"163 ","pages":"Article 107967"},"PeriodicalIF":4.1,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-21DOI: 10.1016/j.ultras.2026.107972
Dingcheng Ji , Wenhao Li , Fei Gao , Jiadong Hua , Jing Lin
The increasing demand for high-accuracy damage quantification in carbon fiber reinforced plastics (CFRP) has led to the widespread adoption of ultrasonic Lamb wave testing (ULWT) for non-destructive testing (NDT) in various engineering applications. The non-contact Scanning Laser Doppler Vibrometer (SLDV) has emerged as a valuable tool for damage evaluation. However, despite significant research on Lamb wavefield analysis methods, the rapid and reliable acquisition of full wavefield data remains a substantial challenge, limiting SLDV’s applicability in real-world engineering scenarios. This study presents a novel deep learning-based approach to reconstructing full wavefield data from highly under-sampled wavefield data using the Spatial-Temporal Masked AutoEncoder (STMAE). By leveraging time-series high-sparsity Lamb wavefield data, our method achieves remarkable reconstruction performance with a sampling ratio as low as 5%. Furthermore, we propose a novel scanning path optimization method based on Bayesian Optimization, which generates adaptive sparse spatial sampling patterns for wavefield reconstruction. The integration of this adaptive sampling pattern with the STMAE, termed as AdaSTMAE, yields lower precision wavefield prediction error around the damage areas. A comprehensive parametric study on the sampling ratio was conducted and validated through comparative experiments in both single-damage, multi-damage scenarios. The implementation of the adaptive sampling strategy resulted in a 2–16% reduction in reconstruction error for single-damage scenarios and a 0.7–5% reduction for multi-damage scenarios around damage areas, compared to scenarios without the adaptive strategy. Our experimental results demonstrate the outstanding performance of the proposed technique in wavefield reconstruction, achieving an 87–88% reduction in reconstruction error relative to the original masked autoencoder (MAE) across different sampling ratios (5%-25%). Additionally, cross-structural validation using composite blades with variable thickness confirmed the model’s strong generalization capability, effectively reconstructing wavefront distortion and velocity variation without fine-tuning.
{"title":"Adaptive sampling for efficient Lamb wavefield reconstruction in composite laminates with Spatial-Temporal Masked AutoEncoder","authors":"Dingcheng Ji , Wenhao Li , Fei Gao , Jiadong Hua , Jing Lin","doi":"10.1016/j.ultras.2026.107972","DOIUrl":"10.1016/j.ultras.2026.107972","url":null,"abstract":"<div><div>The increasing demand for high-accuracy damage quantification in carbon fiber reinforced plastics (CFRP) has led to the widespread adoption of ultrasonic Lamb wave testing (ULWT) for non-destructive testing (NDT) in various engineering applications. The non-contact Scanning Laser Doppler Vibrometer (SLDV) has emerged as a valuable tool for damage evaluation. However, despite significant research on Lamb wavefield analysis methods, the rapid and reliable acquisition of full wavefield data remains a substantial challenge, limiting SLDV’s applicability in real-world engineering scenarios. This study presents a novel deep learning-based approach to reconstructing full wavefield data from highly under-sampled wavefield data using the Spatial-Temporal Masked AutoEncoder (STMAE). By leveraging time-series high-sparsity Lamb wavefield data, our method achieves remarkable reconstruction performance with a sampling ratio as low as 5%. Furthermore, we propose a novel scanning path optimization method based on Bayesian Optimization, which generates adaptive sparse spatial sampling patterns for wavefield reconstruction. The integration of this adaptive sampling pattern with the STMAE, termed as AdaSTMAE, yields lower precision wavefield prediction error around the damage areas. A comprehensive parametric study on the sampling ratio was conducted and validated through comparative experiments in both single-damage, multi-damage scenarios. The implementation of the adaptive sampling strategy resulted in a 2–16% reduction in reconstruction error for single-damage scenarios and a 0.7–5% reduction for multi-damage scenarios around damage areas, compared to scenarios without the adaptive strategy. Our experimental results demonstrate the outstanding performance of the proposed technique in wavefield reconstruction, achieving an 87–88% reduction in reconstruction error relative to the original masked autoencoder (MAE) across different sampling ratios (5%-25%). Additionally, cross-structural validation using composite blades with variable thickness confirmed the model’s strong generalization capability, effectively reconstructing wavefront distortion and velocity variation without fine-tuning.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"162 ","pages":"Article 107972"},"PeriodicalIF":4.1,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146067304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-20DOI: 10.1016/j.ultras.2026.107970
Vindhyesh Pandey, S.S. Mishra
Cracks in concrete buildings, pavements and bridges are important signs of structural deterioration and present serious concerns to integrity and safety. Tradionally, manual inspection has been in use to detect the cracks which is labour-intensive, subjective and prone to errors. Recently, researchers have evolved an advanced automated techniques such as YOLO (You Only Look Once), to overcome the manual errors. Continuous refinements have led to the developments of sophisticated versions YOLOv4 to YOLOv11 in the YOLO series. This study suggests a customisation of YOLOv11, for the purpose of its quickness, high accuracy and recall. Using data augmentation, hyperparameter optimisation and transfer learning on a composite dataset of concrete crack images, this model is specifically customized for crack detection. Based on experimental and publicly accessible data like SDNET2018 (Structural Defects Network), this customized version outperforms baseline versions YOLOv5, YOLOv8, YOLOv9, YOLOv10 and YOLOv11. An mAP50 (mean Average Precision) value of 68.6% is achieved which is 3.47% higher as compared to YOLOv11. Similarly, a precision of 80.8% and recall of 63.6% are achieved. The study provides 50, 100, 200, 300 and 400 epochs for training and validation. The 100 layers and 6.3 GFLOPs (Giga Floating Point Operations Per Second) of this model are also very less compared to other given models which is an indicator of less complex model. This model has proved computationally efficient and suitable for real-time applications and robust to challenging conditions such as low contrast and complex backgrounds, making it a valuable tool for structural health monitoring.
混凝土建筑物、路面和桥梁的裂缝是结构恶化的重要标志,对完整性和安全构成严重关切。传统上,人工检查一直用于检测裂缝,这是劳动密集型的,主观的,容易出错。最近,研究人员开发了一种先进的自动化技术,如YOLO (You Only Look Once),以克服人工错误。不断的改进导致了YOLO系列中复杂版本YOLOv4到YOLOv11的发展。本研究建议对YOLOv11进行定制,以提高其速度、准确性和召回率。在混凝土裂缝图像的复合数据集上使用数据增强、超参数优化和迁移学习,该模型是专门为裂缝检测定制的。基于SDNET2018(结构缺陷网络)等实验和公开可访问的数据,该定制版本优于基准版本YOLOv5, YOLOv8, YOLOv9, YOLOv10和YOLOv11。mAP50 (mean Average Precision)值达到68.6%,比YOLOv11高3.47%。同样,准确率为80.8%,召回率为63.6%。本研究提供了50、100、200、300和400个epoch用于训练和验证。与其他给定模型相比,该模型的100层和6.3 GFLOPs(每秒千兆浮点运算)也非常少,这是一个不太复杂的模型的指标。该模型已被证明具有计算效率,适合实时应用,并且对低对比度和复杂背景等具有挑战性的条件具有鲁棒性,使其成为结构健康监测的宝贵工具。
{"title":"Lightweight frameworks for real-time crack monitoring in civil infrastructure","authors":"Vindhyesh Pandey, S.S. Mishra","doi":"10.1016/j.ultras.2026.107970","DOIUrl":"10.1016/j.ultras.2026.107970","url":null,"abstract":"<div><div>Cracks in concrete buildings, pavements and bridges are important signs of structural deterioration and present serious concerns to integrity and safety. Tradionally, manual inspection has been in use to detect the cracks which is labour-intensive, subjective and prone to errors. Recently, researchers have evolved an advanced automated techniques such as YOLO (You Only Look Once), to overcome the manual errors. Continuous refinements have led to the developments of sophisticated versions YOLOv4 to YOLOv11 in the YOLO series. This study suggests a customisation of YOLOv11, for the purpose of its quickness, high accuracy and recall. Using data augmentation, hyperparameter optimisation and transfer learning on a composite dataset of concrete crack images, this model is specifically customized for crack detection. Based on experimental and publicly accessible data like SDNET2018 (Structural Defects Network), this customized version outperforms baseline versions YOLOv5, YOLOv8, YOLOv9, YOLOv10 and YOLOv11. An mAP50 (mean Average Precision) value of 68.6% is achieved which is 3.47% higher as compared to YOLOv11. Similarly, a precision of 80.8% and recall of 63.6% are achieved. The study provides 50, 100, 200, 300 and 400 epochs for training and validation. The 100 layers and 6.3 GFLOPs (Giga Floating Point Operations Per Second) of this model are also very less compared to other given models which is an indicator of less complex model. This model has proved computationally efficient and suitable for real-time applications and robust to challenging conditions such as low contrast and complex backgrounds, making it a valuable tool for structural health monitoring.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"162 ","pages":"Article 107970"},"PeriodicalIF":4.1,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-20DOI: 10.1016/j.ultras.2026.107968
Nahae Kim, In-Hwan Yang
Electrical signals driving piezoelectric transducers in acoustofluidic applications are crucial for acoustic manipulation efficiency, as sinusoidal wave excitation at the resonance frequency determines the acoustic radiation force in application systems. In this study, particle levitation in half-wavelength ultrasonic standing wave fields generated by both continuous-wave and tone-burst excitations of a cylindrical microresonator was investigated by measuring the average velocity of levitating particles and their equilibrium positions. The dependence of these parameters on the characteristics of the sinusoidal voltage amplitude applied to the resonator was examined by evaluating the net force exerting on spherical fluorescent microparticles, including the time-averaged effect of tone-burst excitation. A semi-empirical correlation was proposed to predict the average energy density of the established standing wave field in the resonator. By incorporating a correction factor that quantitatively accounts for the time-averaged effect over the tone-burst repetition period, the model allows one to evaluate the average energy density of half-wavelength ultrasonic standing wave fields generated by continuous-wave and tone-burst voltage amplitudes. The predicted values in good agreement, within less than 18 % of the experimental measurements.
{"title":"Particle levitation in tone-burst-excited half-wavelength ultrasonic standing waves in cylindrical microresonator","authors":"Nahae Kim, In-Hwan Yang","doi":"10.1016/j.ultras.2026.107968","DOIUrl":"10.1016/j.ultras.2026.107968","url":null,"abstract":"<div><div>Electrical signals driving piezoelectric transducers in acoustofluidic applications are crucial for acoustic manipulation efficiency, as sinusoidal wave excitation at the resonance frequency determines the acoustic radiation force in application systems. In this study, particle levitation in half-wavelength ultrasonic standing wave fields generated by both continuous-wave and tone-burst excitations of a cylindrical microresonator was investigated by measuring the average velocity of levitating particles and their equilibrium positions. The dependence of these parameters on the characteristics of the sinusoidal voltage amplitude applied to the resonator was examined by evaluating the net force exerting on spherical fluorescent microparticles, including the time-averaged effect of tone-burst excitation. A semi-empirical correlation was proposed to predict the average energy density of the established standing wave field in the resonator. By incorporating a correction factor that quantitatively accounts for the time-averaged effect over the tone-burst repetition period, the model allows one to evaluate the average energy density of half-wavelength ultrasonic standing wave fields generated by continuous-wave and tone-burst voltage amplitudes. The predicted values in good agreement, within less than 18 % of the experimental measurements.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"162 ","pages":"Article 107968"},"PeriodicalIF":4.1,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-20DOI: 10.1016/j.ultras.2026.107971
Sukanya Basu , Saptarshi Sasmal
In the case of concrete, the predominant damages develop at the microscale level, mostly at a length lesser than the size of inclusions. Again, if the vibrational energy induced by the dynamic loading does not get effectively dissipated by cement-based materials, it may prolong the original micro-defects that strike down the structural durability and safety. Such nontrivial and sensitive investigations require detailed inspection. The incoherent diffuse ultrasonic wave energy carries essential information about the material microstructure. Analysis based on statistical diffusion theory derives two parameters- diffusivity (D) and dissipation (σ), where, D reflects the material microstructure and σ indicates the material’s viscoelastic property and damping effect. Initially, a numerical study is performed for understanding on wave-matter interaction in two scales of heterogeneity (concrete, cement paste) using diffusion-based analysis, so that role of inclusion (in cementitious matrix) on diffusion can be brought out in an uncoupled manner. The diffusivity parameters depend on tortuosity of wave path, transmission modes and the corresponding excitation frequencies. For experimental purpose, prismatic specimens are cast in two scales; ultrasonic measurements are taken with two excitation frequencies (200 and 300 kHz) under three transmission modes (direct, semi-direct, indirect). Signal processing in the Time-Frequency domain is performed to find the characteristic differences in the material microstructures at the same age of hydration (28 days) for both samples. The Spectral Energy Density of the signals provides information on spectral energy over the time window for a particular wave field. In this study, the influence of microstructure in wave propagation is explicitly demonstrated, and theoretical explanations are quantitatively validated with the actual experimental measurements.
{"title":"Experimental and numerical simulations of ultrasonic wave- multi-phase matter interactions in cement-based composites","authors":"Sukanya Basu , Saptarshi Sasmal","doi":"10.1016/j.ultras.2026.107971","DOIUrl":"10.1016/j.ultras.2026.107971","url":null,"abstract":"<div><div>In the case of concrete, the predominant damages develop at the microscale level, mostly at a length lesser than the size of inclusions. Again, if the vibrational energy induced by the dynamic loading does not get effectively dissipated by cement-based materials, it may prolong the original micro-defects that strike down the structural durability and safety. Such nontrivial and sensitive investigations require detailed inspection. The incoherent diffuse ultrasonic wave energy carries essential information about the material microstructure. Analysis based on statistical diffusion theory derives two parameters- diffusivity (D) and dissipation (σ), where, D reflects the material microstructure and σ indicates the material’s viscoelastic property and damping effect. Initially, a numerical study is performed for understanding on wave-matter interaction in two scales of heterogeneity (concrete, cement paste) using diffusion-based analysis, so that role of inclusion (in cementitious matrix) on diffusion can be brought out in an uncoupled manner. The diffusivity parameters depend on tortuosity of wave path, transmission modes and the corresponding excitation frequencies. For experimental purpose, prismatic specimens are cast in two scales; ultrasonic measurements are taken with two excitation frequencies (200 and 300 kHz) under three transmission modes (direct, semi-direct, indirect). Signal processing in the Time-Frequency domain is performed to find the characteristic differences in the material microstructures at the same age of hydration (28 days) for both samples. The Spectral Energy Density of the signals provides information on spectral energy over the time window for a particular wave field. In this study, the influence of microstructure in wave propagation is explicitly demonstrated, and theoretical explanations are quantitatively validated with the actual experimental measurements.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"162 ","pages":"Article 107971"},"PeriodicalIF":4.1,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-17DOI: 10.1016/j.ultras.2026.107966
Guangdong Zhang , Meng Wang , Othmane Achouham , Umar Amjad , Hamad Alnuaimi , Charfeddine Mechri , Rachid EI Guerjouma , Tribikram Kundu
The sideband peak count–index (SPC-I) technique has been widely used to assess material nonlinearity. However, its ability to capture true nonlinear responses of materials and structures has not convinced some researchers yet. This is because SPC-I variations can be generated by both linear scattering effects and nonlinear responses. Since changes in linear scattering modes can also influence SPC-I values, it is sometimes difficult to determine whether the observed variations stem from material nonlinearity or purely from linear scatterings. This work investigates whether SPC-I is sensitive to the variation in material nonlinearity. It also gives clear guidelines on how the upper and lower bounds of the moving threshold line should be set for capturing the linear and nonlinear variations separately, or together as a hybrid technique. Numerical simulations are conducted using an isotropic nonlinear elastic material (a hyperelastic material) modeled as a “Murnaghan material” characterized by second- and third-order elastic constants (SOECs and TOECs). Linear elastic (classic theory of linear elasticity) and nonlinear elastic plates are excited at different amplitudes for comparison and the amplification factor (AF) for these excitations is defined as the ratio of the input ultrasonic excitation to its baseline value (the first input excitation value). Numerical results demonstrate that for different AF values, SPC-I computed from normalized spectral plots remains constant for linear materials but varies for nonlinear materials. This trend is also observed for nonlinear elastoplastic materials in another sets of numerical modeling. Experimental measurements on aluminum and carbon fiber composite plates confirm the findings of the numerical modeling based observations that SPC-I can capture the nonlinear responses, reinforcing its significance in material characterization and damage detection. Finally, this capability of SPC-I is used for solving a real-world structural health monitoring (SHM) problem – monitoring bolt-loosening – where SPC-I responses and resonance frequency shifts are shown to follow similar trends. Both techniques are capable of tracking evolving contact conditions from bolt loosening while the SPC-I technique is easier to implement.
{"title":"Validating sideband peak count-index (SPC-I) technique as a hybrid linear/nonlinear ultrasonic technique through numerical modeling and experiment","authors":"Guangdong Zhang , Meng Wang , Othmane Achouham , Umar Amjad , Hamad Alnuaimi , Charfeddine Mechri , Rachid EI Guerjouma , Tribikram Kundu","doi":"10.1016/j.ultras.2026.107966","DOIUrl":"10.1016/j.ultras.2026.107966","url":null,"abstract":"<div><div>The sideband peak count–index (SPC-I) technique has been widely used to assess material nonlinearity. However, its ability to capture true nonlinear responses of materials and structures has not convinced some researchers yet. This is because SPC-I variations can be generated by both linear scattering effects and nonlinear responses. Since changes in linear scattering modes can also influence SPC-I values, it is sometimes difficult to determine whether the observed variations stem from material nonlinearity or purely from linear scatterings. This work investigates whether SPC-I is sensitive to the variation in material nonlinearity. It also gives clear guidelines on how the upper and lower bounds of the moving threshold line should be set for capturing the linear and nonlinear variations separately, or together as a hybrid technique. Numerical simulations are conducted using an isotropic nonlinear elastic material (a hyperelastic material) modeled as a “Murnaghan material” characterized by second- and third-order elastic constants (SOECs and TOECs). Linear elastic (classic theory of linear elasticity) and nonlinear elastic plates are excited at different amplitudes for comparison and the amplification factor (AF) for these excitations is defined as the ratio of the input ultrasonic excitation to its baseline value (the first input excitation value). Numerical results demonstrate that for different AF values, SPC-I computed from normalized spectral plots remains constant for linear materials but varies for nonlinear materials. This trend is also observed for nonlinear elastoplastic materials in another sets of numerical modeling. Experimental measurements on aluminum and carbon fiber composite plates confirm the findings of the numerical modeling based observations that SPC-I can capture the<!--> <!-->nonlinear responses, reinforcing its significance in material characterization and damage detection. Finally, this capability of SPC-I is used for solving a real-world structural health monitoring (SHM) problem – monitoring bolt-loosening – where SPC-I responses and resonance frequency shifts are shown to follow similar trends. Both techniques are capable of tracking evolving contact conditions from bolt loosening while the SPC-I technique is easier to implement.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"162 ","pages":"Article 107966"},"PeriodicalIF":4.1,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146020080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Developing high wear resistance is crucial for the application of magnesium alloy components under extreme service conditions. In this study, temperature-assisted ultrasonic shot peening (TUSP) incorporating graphene particles was applied to enhance the surface properties of AZ91D magnesium alloy. A composite reinforced surface layer, consisting of micro-dimples, a graphene coating, and a gradient-hardened layer, was successfully fabricated on the surface. The samples treated by low temperature-assisted ultrasonic shot peening (LTUSP) achieved the highest surface hardness of 146.6 HV, corresponding to increases of approximately 69.7% and 23.0% compared with the untreated and conventional USP-treated samples, respectively. The tribological properties of the treated samples were evaluated using a ball-on-disc rotational friction tribometer under normal loads of 5, 7.5, and 10 N, with sliding speeds of 20, 30, and 40 r/min. At a normal load of 5 N and a sliding speed of 30 r/min, the LTUSP-treated samples exhibited a wear rate of approximately 1.63 × 10−4 mm3/N·m, representing reductions of 91.8% and 54.5% relative to the untreated and conventional USP samples, respectively. An in-depth study revealed that the enhanced wear resistance was primarily attributed to the composite reinforced layer, which mitigated three-body wear, direct contact, and shear failure during the sliding process. This work presents a viable approach for enhancing the wear resistance of AZ91D magnesium alloy.
{"title":"Composite layer formation on AZ91D magnesium alloy via temperature-assisted ultrasonic shot peening for enhanced wear resistance","authors":"Jinrui Xiao , Xu Liang , Sentao Diao , Xincheng Xie , Lilin Zhang , Zhongwei Liang","doi":"10.1016/j.ultras.2026.107965","DOIUrl":"10.1016/j.ultras.2026.107965","url":null,"abstract":"<div><div>Developing high wear resistance is crucial for the application of magnesium alloy components under extreme service conditions. In this study, temperature-assisted ultrasonic shot peening (TUSP) incorporating graphene particles was applied to enhance the surface properties of AZ91D magnesium alloy. A composite reinforced surface layer, consisting of micro-dimples, a graphene coating, and a gradient-hardened layer, was successfully fabricated on the surface. The samples treated by low temperature-assisted ultrasonic shot peening (LTUSP) achieved the highest surface hardness of 146.6 HV, corresponding to increases of approximately 69.7% and 23.0% compared with the untreated and conventional USP-treated samples, respectively. The tribological properties of the treated samples were evaluated using a ball-on-disc rotational friction tribometer under normal loads of 5, 7.5, and 10 N, with sliding speeds of 20, 30, and 40 r/min. At a normal load of 5 N and a sliding speed of 30 r/min, the LTUSP-treated samples exhibited a wear rate of approximately 1.63 × 10<sup>−4</sup> mm<sup>3</sup>/N·m, representing reductions of 91.8% and 54.5% relative to the untreated and conventional USP samples, respectively. An in-depth study revealed that the enhanced wear resistance was primarily attributed to the composite reinforced layer, which mitigated three-body wear, direct contact, and shear failure during the sliding process. This work presents a viable approach for enhancing the wear resistance of AZ91D magnesium alloy.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"162 ","pages":"Article 107965"},"PeriodicalIF":4.1,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146019919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}