Ultrasonics最新文献

{"title":"Anisotropic properties of fracture zone in sandstone inferred from seismic moment tensors of acoustic emissions","authors":"Václav Vavryčuk ,&nbsp;Matěj Petružálek ,&nbsp;Tomáš Lokajíček","doi":"10.1016/j.ultras.2025.107832","DOIUrl":"10.1016/j.ultras.2025.107832","url":null,"abstract":"<div><div>We present an inversion for elastic anisotropy parameters of rocks using a large set of accurate moment tensors (MTs) derived from acoustic emissions (AEs). This method is demonstrated using AEs observed in a sandstone sample during a semi-circular bend test. We inverted 539 highly accurate MTs of AEs and retrieved both the orientation of anisotropy axes and elastic parameters defining the orthorhombic anisotropy within the fracture zone that developed in the sample during the test. The anisotropy results from the presence of aligned cracks in the fracture zone and the background transverse isotropy of the sandstone specimen. The observed anisotropy is moderate, with strengths of 18%, 14% and 21% for the P, S1 and S2 waves, respectively. We show that neglecting this anisotropy introduces a significant bias when estimating crack orientation and tensility from MTs. When anisotropy effects are accounted for by recalculating moment tensors into source tensors, the scatter in crack orientations is reduced, and the slope angle, which characterizes crack tensility, is systematically increased by approximately 10°. Our results confirm that the presented inversion method is a powerful and robust tool, capable of analyzing anisotropy in rocks, even in cases of low anisotropy symmetry.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"159 ","pages":"Article 107832"},"PeriodicalIF":4.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145259297","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}

{"title":"Advancing ex-vivo meniscus tissue characterization: sensitivity and accuracy of shear modulus measurements via supersonic shear imaging vs. biomechanical testing","authors":"Sayed Shahabodin Hashemi ,&nbsp;Jose Luis Martin-Rodriguez ,&nbsp;Angel Ruiz Molina ,&nbsp;Antonio Manuel Callejas Zafra ,&nbsp;Guillermo Rus","doi":"10.1016/j.ultras.2025.107771","DOIUrl":"10.1016/j.ultras.2025.107771","url":null,"abstract":"<div><div>Non-invasive measurement of meniscal mechanical properties is critical for advancing both meniscal pathophysiology research and represents a critical advancement in musculoskeletal diagnostics. This study aimed to evaluate the accuracy and sensitivity of ultrasound-based stiffness measurements using Supersonic Shear Imaging (SSI) compared to low-strain and high-strain tensile testing and to assess the ability of SSI to detect meniscal degeneration. Sixty bovine menisci were analyzed across seven regions, covering including the tibial and femoral layers, as well as the circumferential region, using shear wave elastography (SWE) and tensile testing. To evaluate tissue degeneration, samples underwent mechanical testing both before and after being subjected to five freeze–thaw cycles. Shear stiffness values obtained from SSI were compared against tensile-derived parameters, including shear modulus at low strain, linear stiffness, and Young’s modulus measured from stress–strain curves up to failure, assuming small-amplitude shear wave propagation. Depth-dependent effects in Region of Interest (ROI) selection were evaluated, and Different SSI transducers were assessed using various receiver tests. Our results demonstrate significant agreement between SSI measurements and mechanical properties: 88 % sensitivity for stiffness and Young’s modulus in circumferential samples, and 91 % for shear modulus at 3 % strain in femoral and tibial regions. While intact samples showed strong positive correlations between stiffness measures, degenerated tissue exhibited inverse relationships. Our comprehensive transducer comparison and receiver tests yielded optimized protocols for ROI selection. Crucially, we identify for depth-dependent measurement artifacts, proposing the ROI selection guidelines specific to meniscal elastography. This depth-aware acquisition strategy, together with the observed sensitivity of SSI to degeneration (p &lt; 0.001), supports its clinical utility in contexts where conventional ultrasound elastography is limited. Overall, these findings validate SSI as a sensitive technique for biomechanical assessment of the meniscus, with direct translational potential for diagnosing degeneration and monitoring post/pre surgical tissue remodeling.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"159 ","pages":"Article 107771"},"PeriodicalIF":4.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145233506","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}

{"title":"A comparative evaluation of two subharmonic-aided pressure estimation (SHAPE) analysis methods","authors":"Hailee Mayer ,&nbsp;Priscilla Machado ,&nbsp;Trang Vu ,&nbsp;Annalisa Berzigotti ,&nbsp;Jaume Bosch ,&nbsp;Elton Dajti ,&nbsp;Antonina Antonenko ,&nbsp;Kirk Wallace ,&nbsp;Flemming Forsberg","doi":"10.1016/j.ultras.2025.107840","DOIUrl":"10.1016/j.ultras.2025.107840","url":null,"abstract":"<div><div>Pressure measurement in clinical practice is a valuable tool for diagnostic evaluation, especially in diseases such as portal hypertension. Currently, portal pressures are measured by invasive hepatic vein catheterization, posing risks to patients, and limiting how often measurements can be obtained. Subharmonic-aided pressure estimation (SHAPE) is an ultrasound-based technique that leverages ultrasound contrast agents (UCAs) to estimate changes in hydrostatic pressure. UCAs act as nonlinear oscillators when exposed to high enough acoustic pressures (typically &gt; 200 kPa) and produce significant energy components ranging from subharmonics to higher harmonics. Tissues do not generate significant subharmonic components, thus making it the optimal component for SHAPE. SHAPE is performed using subharmonic imaging complimented by an acoustic pressure optimization algorithm to induce the highest sensitivity to hydrostatic pressure in the UCAs. Traditionally, multiple acquisitions of contrast clips are used to identify the subharmonic amplitude and calculate SHAPE parameters, but recently, a faster method of SHAPE has been proposed, utilizing only the acoustic pressure optimization algorithm to obtain subharmonic amplitudes. The objective of this work is to compare the two methods, SHAPE and fast-SHAPE, in the same patients, to explore the utility of fast-SHAPE.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"159 ","pages":"Article 107840"},"PeriodicalIF":4.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222879","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}

{"title":"Simulation and experimental studies on the hydrodynamic behavior and induced erosion characteristics of ultrasonic cavitation","authors":"Chenwei Dai ,&nbsp;Xingwang Chen ,&nbsp;Qing Miao ,&nbsp;Zhen Yin ,&nbsp;Ming Zhang ,&nbsp;Jiajia Chen","doi":"10.1016/j.ultras.2025.107851","DOIUrl":"10.1016/j.ultras.2025.107851","url":null,"abstract":"<div><div>Ultrasonic cavitation has garnered extensive attention for its potential in surface modification due to its characteristics such as microjet impingement and high-pressure shockwaves generated during bubble collapse. Although the collapse dynamics of a single bubble have been widely examined, researches on the global fluid behavior remains insufficient. This study establishes a numerical model of ultrasonic cavitation with the aim of systematically examining how ultrasonic amplitude, ultrasonic frequency and standoff distance affect the bubble distribution and the absolute pressure in the fluid domain. On this basis, experiments were also conducted using a self-developed ultrasonic vibration device to investigate the cavitation erosion on aluminum alloy by measuring the surface morphology and roughness. The results show that the cavitation bubbles are primarily distributed within 0.7 mm beneath the tool end, reaching a peak absolute pressure of 4.22 MPa when the standoff distance is 1 mm. When the ultrasonic amplitude is increased, the peak absolute pressure is enlarged from 0.74 MPa to 3.53 MPa, the peak vapor volume fraction is increased from 6.5 % to 34.8 %, and the surface roughness of eroded workpiece is raised from 0.110 μm to 1.013 μm, with surface morphology evolving from microscopic pits to large-scale material removal. The vapor volume fraction reaches the maximum value of 97 % at a standoff distance of 0.25 mm, but sharply decreases to 0.08 % at 2 mm. The workpiece is most severely eroded to the largest roughness of 1.013 μm at the standoff distance of 0.5 mm. When the ultrasonic frequency is brought up, the peak absolute pressure is progressively increased, but the peak vapor volume fraction is diminished with accelerated change rate. Low-frequency ultrasonic vibration produces stronger impacts by fewer large bubbles, whereas high-frequency ultrasonic vibration generates weaker impacts by numerous small bubbles. The simulation and experimental results demonstrate strong agreement with each other, which provides deeper insights into the erosion mechanisms induced by ultrasonic cavitation. This article will enrich the fundamental theory of ultrasonic cavitation and provides theoretical support and guidance for material modification using ultrasonic cavitation.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"159 ","pages":"Article 107851"},"PeriodicalIF":4.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145293855","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}

{"title":"Experimental characterization of a defect separating two poroelastic plates","authors":"Mehdi Mohammed,&nbsp;Pierre Maréchal,&nbsp;Abdellah Alem,&nbsp;Hervé Franklin,&nbsp;Huaqing Wang","doi":"10.1016/j.ultras.2025.107848","DOIUrl":"10.1016/j.ultras.2025.107848","url":null,"abstract":"<div><div>The detection of erosion is essential in engineering and material science, especially where progressive degradation can influence the performance of structures leading to stability problems. The present study investigates the potential use of acoustic waves in detecting degradation in the material and characterizing it in porous media systems. A multilayer system, where the porous plates are separated by a fluid layer, has been studied to show how variations in the fluid layer distance alter the acoustic wave behavior. Theoretical models based on Biot’s theory have been used and measurements were made experimentally by incrementing the thickness of the fluid layer from 0 to 11 mm and analyzing reflection coefficients over a variety of frequencies. Experimental results are compablue with theoretical modeling and while the model aligns with experimental results, some divergence occurs, possibly due to the complex nature of the medium. The comparison of the various water-layer thicknesses gives valuable information on acoustic-wave propagation in porous materials and demonstrates a way of evaluating the degree of erosion from layer thickness spacing variations.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"159 ","pages":"Article 107848"},"PeriodicalIF":4.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145330216","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}

{"title":"A miniature wireless robotic swimmer actuated by a vector acoustic system","authors":"Xin Wang ,&nbsp;Le Wang ,&nbsp;Hanlin Wang ,&nbsp;Xiqing Zuo ,&nbsp;Rongyang Wang ,&nbsp;Xianglei Zhang ,&nbsp;Chao Xu","doi":"10.1016/j.ultras.2025.107880","DOIUrl":"10.1016/j.ultras.2025.107880","url":null,"abstract":"<div><div>Untethered underwater robots are capable of navigating confined aquatic environments, offering significant potential for applications such as environmental monitoring, pipeline inspection and biological sample collection. However, traditional propeller propulsion systems suffer from limited maneuverability and potential safety risks in confined spaces. To address these challenges, we propose a miniature robotic swimmer (8.5 cm in diameter and 10 cm in height) actuated by a vector acoustic system. Specifically, the robot employs a piezoelectric transducer to generate high-intensity ultrasonic waves, which produce a directional jet in the fluid by acoustic radiation force. By using a miniature electromagnetic motor to adjust the alignment of the piezoelectric actuator, the system can modify the jet direction, achieving full-range propulsion without turning radius limitations. Moreover, the combined implementation of a vectorized propulsion system with a wireless control module enables superior maneuverability. Experiments show that the robot achieves a maximum linear velocity of 79.2 mm/s and can traverse a narrow gap of 1.5 times the body length under remote wireless control, demonstrating excellent maneuverability and obstacle avoidance capability.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"159 ","pages":"Article 107880"},"PeriodicalIF":4.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425019","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}

{"title":"A stochastic approach for calculating elastic constants of polymer lattice structures based on spectral ultrasonic data","authors":"Abdullah Al Masud ,&nbsp;Paul F Egan ,&nbsp;Jingfei Liu ,&nbsp;Karl A Fisher","doi":"10.1016/j.ultras.2025.107870","DOIUrl":"10.1016/j.ultras.2025.107870","url":null,"abstract":"<div><div>Additively manufactured polymer lattices are increasingly used in biomedical and structural applications due to their tunable mechanical properties and architectural similarity to biological materials. However, accurately resolving their anisotropic elastic response remains challenging due to fabrication inconsistencies, energy loss mechanisms, and differences between static and dynamic characterization techniques. In this study, a dynamic technique, resonant ultrasound spectroscopy (RUS) was applied to a stereolithography-fabricated body-centered tetragonal (BC-Tetra) lattice composed of a polyurethane-like resin. Elastic constants were extracted from both experimental and model (FEA) eigenfrequencies using a particle swarm optimization (PSO) scheme with modified parameter tuning to improve exploration of the non-convex inversion space. Comparison of inverted elastic tensors showed strong agreement for the axial stiffness,<span><math><mrow><mspace></mspace><msub><mi>C</mi><mn>33</mn></msub><mspace></mspace></mrow></math></span> and shear-related coefficients <span><math><mrow><mspace></mspace><msub><mi>C</mi><mn>44</mn></msub></mrow></math></span>​ and <span><math><mrow><mspace></mspace><msub><mi>C</mi><mn>66</mn></msub></mrow></math></span>, , while in-plane stiffness constants <span><math><mrow><mspace></mspace><msub><mi>C</mi><mn>11</mn></msub></mrow></math></span>​ and <span><math><mrow><mspace></mspace><msub><mi>C</mi><mn>12</mn></msub></mrow></math></span>​ and the axial coupling term <span><math><mrow><mspace></mspace><msub><mi>C</mi><mn>13</mn></msub><mspace></mspace></mrow></math></span> exhibited the greatest variance, reflecting inversion sensitivity and the limited number of resonances below the continuum cutoff. Engineering moduli derived from RUS were internally consistent and in-plane values agreed closely with FEA predictions, but quasi-static measurements of the in-plane moduli <span><math><mrow><mspace></mspace><msub><mi>E</mi><mn>1</mn></msub><mo>=</mo><msub><mi>E</mi><mn>2</mn></msub></mrow></math></span> and out-of-plane modulus <span><math><mrow><mspace></mspace><msub><mi>E</mi><mn>3</mn></msub><mspace></mspace></mrow></math></span> were 20 % and 32 % lower, respectively. This divergence highlights fundamental differences in compliance across loading regimes: quasi-static compression is strongly influenced by strut bending, resin pooling, and boundary effects, whereas RUS probes free–free global vibrational modes that enforce affine deformation at the scale of the entire lattice, suppressing local compliance mechanisms and yielding higher effective moduli. Our study is an effort to test the boundaries of RUS for high-loss polymer lattices and to develop practices that could eventually reduce operator dependence.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"159 ","pages":"Article 107870"},"PeriodicalIF":4.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145318767","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}

{"title":"Optimized Apodizations with Training Simulations (OATS): Learned depth-dependent apodizations via differentiable beamforming for reduced operator tuning","authors":"Di Xiao ,&nbsp;Hassan Nahas ,&nbsp;Misaki Hiroshima ,&nbsp;Aya Kishimoto ,&nbsp;Alfred C.H. Yu","doi":"10.1016/j.ultras.2025.107827","DOIUrl":"10.1016/j.ultras.2025.107827","url":null,"abstract":"<div><div>Ultrasound is a point-of-care imaging modality that allows for real-time operation. While real-time capabilities are advantageous, one potential concern is the operator dependency of the modality as settings selected by the operator can alter the image appearance. Improvement of the B-mode image to necessitate fewer adjustments can reduce the operator dependency. Here, we propose a supervised learning framework (Optimal Apodizations with Training Simulations – OATS) to devise new apodization weights for image quality improvement. Our framework relies on the use of a differentiable beamformer to iteratively optimize apodization weights by comparing differences between simulated ground truth images and the corresponding post-beamformed images (simulated training set of over 200 images). We experimentally verified that these apodization weights resulted in higher quality B-mode images on both simulated and real-world data for focused and unfocused imaging scenarios. In the focused imaging scenario, the OATS-apodized images demonstrated reduced sidelobe artifact, improved lateral resolution (11 %), and improved signal equalization across depth when compared to a conventional Hanning apodization. In the unfocused imaging scenario, we observed reduced sidelobe artifacts and improved tissue-to-lesion contrast by up to 13 dB when compared against fixed F-number beamforming. Additionally, the OATS apodization weights were physically interpretable and learned to emulate image formation parameters such as time-gain compensation, F-number limited aperture, and transmit focus through the supervised learning procedure. Overall, the proposed framework successfully learned generalizable receive apodizations to improve image quality.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"159 ","pages":"Article 107827"},"PeriodicalIF":4.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145259294","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}

{"title":"Interpreting material anisotropy through the fractional wave equation","authors":"Ghatu Subhash ,&nbsp;Michael MacIsaac ,&nbsp;Charlie Tran ,&nbsp;Amanda Beck ,&nbsp;Woohyun Eum ,&nbsp;Joel B. Harley","doi":"10.1016/j.ultras.2025.107866","DOIUrl":"10.1016/j.ultras.2025.107866","url":null,"abstract":"<div><div>In the fields of structural health monitoring and non-destructive evaluation (NDE), guided waves are often used for detection of material and structural defects. In this research, we have developed a comprehensive understanding of the generalized superelliptical form of the 2D scalar wave (Helmholtz) equation to predict structural features in anisotropic materials. The exponent of the terms in the superelliptical wave equation was systematically varied, while simultaneously varying the ratio of the wave velocities in two orthogonal directions, to develop 3D maps of wave propagation characteristics in the wavenumber domain as a function of frequency. These wave profiles were then interpreted to reveal structural features and material anisotropy. To validate these predictions, an experimental scheme was designed where a piezoelectric sensor excites a thin specimen, and the ensuing guided wave propagation features were captured on several materials using a laser Doppler vibrometer. The resulting responses in the wavenumber domain were compared against the predicted profiles and a good agreement was observed. Thus, the understanding developed from the superelliptical wave equation and its relationship to a material’s anisotropic structure were experimentally validated on an isotropic material, a uniaxial fiber reinforced composite, and three biaxial composites with different ratios of fiber and matrix stiffnesses. The proposed framework based on guided wave propagation of ultrasonic waves is shown to be a valuable tool to identify structural anisotropy.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"159 ","pages":"Article 107866"},"PeriodicalIF":4.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363813","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}

{"title":"Wearable flexible ultrasonic transducers: materials, applications, and challenges","authors":"Lin Guo ,&nbsp;Jing Liu ,&nbsp;Ying Li ,&nbsp;Ruixia Xu ,&nbsp;Guangsheng Song ,&nbsp;Jianan Wu ,&nbsp;Zhihui Qian ,&nbsp;Lei Ren ,&nbsp;Luquan Ren ,&nbsp;Qiang Zhou","doi":"10.1016/j.ultras.2025.107872","DOIUrl":"10.1016/j.ultras.2025.107872","url":null,"abstract":"<div><div>Flexible Ultrasonic Transducers (FUTs) represent a rapidly evolving technology in wearable medical devices, enabling real-time, noninvasive, and continuous physiological monitoring on curved and moving body surfaces. By combining advanced piezoelectric materials with stretchable electrodes and soft encapsulation layers, FUTs overcome the limitations of traditional rigid transducers, including poor conformability, limited wearability, and the potential to cause pressure-induced deformation of the imaging target. This review first summarizes the working principles and typical architectures of FUTs, highlighting key material systems such as flexible substrates and electrodes, high-performance piezoelectric elements, flexible backing and matching layers, and electronic systems. It also summarizes the applications of FUTs in areas such as novel ultrasound diagnostic methods, ultrasonic treatment, advancing healthcare accessibility, and human–machine interaction. Finally, the paper discusses some of the technical challenges faced by FUTs and their corresponding future works, including long-term wearable performance, miniaturization, wireless capability, and the array element localization problem.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"159 ","pages":"Article 107872"},"PeriodicalIF":4.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145402069","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}