Probe Array Research Articles

Enhancing Image Contrast in Breast USCT Reflection Imaging Using Coherence Factor Beamforming

Abstract Breast cancer is the most common cancer worldwide, and early screening is essential. Existing breast ultrasound is affordable and convenient, but its 2D image quality is poor, and it heavily relies on the doctor’s skills. The novel breast ultrasound computed tomography (USCT) can use a ring array probe to implement hundreds of single transducer emission for full-view focusing synthetic aperture reflection imaging, thereby obtaining high-resolution 3D images. However, single transducer emission results in low acoustic intensity, which further leads to low signal-to-noise ratio and low contrast of reflection images. To improve image contrast, this study incorporated beamforming with coherence factor (CF) into reflection imaging using ring transducers, promising to produce high-contrast USCT reflection images. For evaluation, we developed a USCT prototype with 2048 elements and conducted phantom experiments. We conducted phantom experiments. Results showed that the contrast achieved by the coherence factor method of the breast phantom image is improved from 24.54 dB to 63.18 dB, and the artifacts are significantly suppressed. It can be seen that the CF method could significantly improve the contrast of the breast USCT reflection image.

Multi-angle speed-of-sound imaging with sparse sampling to characterize medical tissue properties

Medical Speed-of-sound (SoS) imaging, which can characterize medical tissue properties better by quantifying their different SoS, is an effective imaging method compared with conventional B-mode ultrasound imaging. As a commonly used diagnostic instrument, a hand-held array probe features convenient and quick inspection. However, artifacts will occur in the single-angle SoS imaging, resulting in indistinguishable tissue boundaries. In order to build a high-quality SoS image, a number of raw data are needed, which will bring difficulties to data storage and processing. Compressed sensing (CS) theory offers theoretical support to the feasibility that a sparse signal can be rebuilt with random but less sampling data. In this study, we proposed an SoS reconstruction method based on CS theory to process signals obtained from a hand-held linear array probe with a passive reflector positioned on the opposite side. The SoS reconstruction method consists of three parts. Firstly, a sparse transform basis is selected appropriately for a sparse representation of the original signal. Then, considering the mathematical principles of SoS imaging, the ray-length matrix is used as a sparse measurement matrix to observe the original signal, which represents the length of the acoustic propagation path. Finally, the orthogonal matching pursuit algorithm is introduced for image reconstruction. The experimental result of the phantom proves that SoS imaging can clearly distinguish tissues that show similar echogenicity in B-mode ultrasound imaging. The simulation and experimental results show that our proposed method holds promising potential for reconstructing precision SoS images with fewer signal samplings, transmission, and storage.

Automatic PAUT crack detection and depth identification framework based on inspection robot and deep learning method

Orthotropic steel bridge decks (OSD) are widely acclaimed for their lightweight, high load-carrying capacity, and adaptability, making them a popular choice in steel structure bridges. However, the complex nature of their structure makes them susceptible to fatigue cracking, posing significant safety concerns. To address the issues above, this study employs a robot equipped with an ultrasonic phased array probe to automate the detection of internal cracks within Orthotropic Steel Decks (OSD). A Deep Convolutional Generative Adversarial Network (DCGAN) is utilized to augment the training dataset of Phased Array Ultrasonic Testing (PAUT) images. The YOLO series algorithms are applied and compared for crack localization, with YOLO v7-tiny exhibiting the highest accuracy and speed. Integrating attention mechanisms into the YOLO v7-tiny algorithm to facilliate rapid and high-precision crack detection. Analyzing the echo region with an echo intensity bar enabled the identification of crack depth, with an identification error within 5%.

New high-field side magnetic probe array system for three-dimensional magnetic fluctuation measurements on EAST

To better study the magnetic fluctuations in the high-field side of EAST tokamak, a new high-field side magnetic probe array (HFS-MPA) has been developed on EAST recently. The HFS-MPA consists of 12 identical three-dimensional (3D) magnetic probes, which are mounted on the HFS wall with carefully designed arrangement. The HFS-MPA magnetic probes bring additional toroidal magnetic fluctuation measurements compared with the HFS regular magnetic probes which can only provide poloidal and radial magnetic fluctuation measurements. The upper limits of frequency and toroidal mode number (n) measurements of the magnetic fluctuations have been improved by comparing HFS-MPA with the HFS regular magnetic probes, i.e., 650 kHz vs 100 kHz and n = 23 vs n = 1. In developing the HFS-MPA diagnostic system, many practical challenges have been overcome and many special designs have been developed. These will be mentioned in the main subsystem description of the HFS-MPA diagnostic in this paper, which might be useful for developing new magnetic probe diagnostics in the future on EAST or other magnetically confined fusion devices. The calibration of the effective area and frequency response of the HFS-MPA is also described. The preliminary application in studying the frequency and propagation characteristics of the magnetic fluctuations with HFS-MPA compared with EAST regular magnetic probes shows that the HFS-MPA is well developed for plasma physics studies.

Aberration correction in 3D transthoracic echocardiography

Three-dimensional cardiac imaging has been available in the clinic for more than two decades. Continuous improvement in image quality has occurred in this period due to the development of probe technology and beamforming techniques. The purpose of this article is to quantitatively and qualitatively analyze the effect of a commercially available aberration correction algorithm on clinically acquired 3D transthoracic echocardiography (3D TTE) images. Clinical triplane and 3D volume cineloops of at least one cardiac cycle of pre-beamformed channel data were captured from 50 patients using a GE HealthCare Vivid E95 system with the 4Vc-D matrix array probe. This resulted in a total of 3200 vol and 3136 triplane frames. The data were post-processed with and without aberration correction. Quantitatively, assessed by an image quality parameter based on coherence, all recordings were improved by aberration correction compared to those without aberration correction. Triplane data obtained a larger improvement in image quality than volume data. Qualitatively, as demonstrated by case examples, aberration-corrected images appear sharper, have a brighter tissue signal compared to the cavity, and provide better delineation of cardiac structures. 3D rendering of valves can also be significantly improved. In general, aberration correction provides a systematic improvement in clinical cardiac triplane and 3D volume images.

Study on the internal waves induced by a submerged body moving in a continuously stratified fluid

This paper studies the characteristics of internal waves induced by the motion of a submerged body through a combination of experimental and numerical methods. First, by deploying an array of conductivity probes in an experiment, the temporal evolution of the internal wave at the plane of the conductivity probe array is obtained and compared with numerical simulation results based on the Navier–Stokes equations, thereby validating the accuracy of the Computational Fluid Dynamics (CFD) model. Subsequently, utilizing CFD calculations, further exploration is conducted on the spatiotemporal distribution characteristics of the internal wave, encompassing its generation and evolution, velocity field distribution, wake angle, and wave profile features. Finally, the variation of the internal wave with the Froude number (Fr) is investigated, revealing that it varies apparently with Fr, including the wave component, wave mode, wake length, wake angle, wave amplitude, and so on. It is found that when Fr is large, the internal wave converges toward the centerline behind the body, until forming a line. The wave magnitude changes with Fr in four stages, i.e., increasing with Fr from zero in the first stage, reaching a peak and decreasing thereafter in the second stage, then changing little in the third stage, and finally increasing approximately linearly in the fourth stage.

Unifying approaches to understanding capacity in change detection.

To navigate changes within a highly dynamic and complex environment, it is crucial to compare current visual representations of a scene to previously formed representations stored in memory. This process of mental comparison requires integrating information from multiple sources to inform decisions about changes within the environment. In the present article, we combine a novel systems factorial technology change detection task (Blunden et al., 2022) with a set size manipulation. Participants were required to detect 0, 1, or 2 changes of low and high detectability between a memory and probe array of 1-4 spatially separated luminance discs. Analyses using systems factorial technology indicated that the processing architecture was consistent across set sizes but that capacity was always limited and decreased as the number of distractors increased. We developed a novel model of change detection based on the statistical principles of basic sampling theory (Palmer, 1990; Sewell et al., 2014). The sample size model, instantiated parametrically, predicts the architecture and capacity results a priori and quantitatively accounted for several key results observed in the data: (a) increasing set size acted to decrease sensitivity (d') in proportion to the square root of the number of items in the display; (b) the effect of redundancy benefited performance by a factor of the square root of the number of changes; and (c) the effect of change detectability was separable and independent of the sample size costs and redundancy benefits. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Identifying grain size in ASTM A36 steel using ultrasonic backscattered signals and machine learning

Ultrasonic nondestructive techniques can be useful tools in the microstructural classification of metallic alloys. Among the most common techniques for characterizing materials, backscattered signal analysis stands out because it does not require a back surface echo. This study classifies five ASTM A36 steel samples with varying grain sizes using ultrasonic waves. For each sample, ultrasound signals were obtained using two ultrasonic array probes with center frequencies of 5 and 10 MHz. An extensive feature engineering process was conducted using the tfresh package in Python, which extracts a wide range of features from time series data, transforming raw ultrasound signals into a structured format. Seven machine learning models were evaluated based on accuracy, precision, recall, and F1 score, with performances ranging from 70 to 100%. The XGBoost model exhibited the best performance with 10 MHz probe signals, achieving 100% accuracy. An additional validation test was conducted to evaluate the models’ generalization capability, considering inter-specimen variabilities. Despite a slight reduction in prediction metrics, the XGBoost model maintained good performance, with accuracy between 89% and 100% across all frequencies. Such findings demonstrate that backscattered grain noise can effectively identify grain sizes provided that an adequate machine learning model is used.

Noninvasive microvascular imaging in newborn rats using high-frequency ultrafast ultrasound

Ultrasound imaging stands as the predominant modality for neonatal health assessment, with recent advancements in ultrafast Doppler (μDoppler) technology offering significant promise in fields such as neonatal brain imaging. Combining μDoppler with high-frequency ultrasound (HF-μDoppler) presents a potential efficient avenue to enhance in vivo microvascular imaging in small animals, notably newborn rats, a crucial preclinical animal model for neonatal disease and development research. It is necessary to verify the imaging performance of HF-μDoppler in preclinical trials. This study investigates the microvascular imaging capabilities of HF-μDoppler using a 30 MHz high-frequency linear array probe in newborn rats. Results demonstrate the clarity of cerebral microvascular imaging in rats aged 1 to 7 postnatal days, extending to whole-body microvascular imaging, encompassing the central nervous system, including the brain and spinal cord. In conclusion, HF-μDoppler technology emerges as a reliable imaging tool, offering a new perspective for preclinical investigations into neonatal diseases and development.

Validation study of a novel diaphragmatic excursion measurement method: evaluation of diaphragmatic excursion by phased-array probe in hepato-renal/spleno-renal section

To investigate the accuracy and reproducibility of diaphragmatic excursion (DE) measurements through hepato-renal/spleno-renal section as a novel method for assessing diaphragmatic function. Twelve healthy participants were recruited. Each participant underwent DE measurements performed by four operators with varying levels of experience using traditional methods (liver/spleen section) and novel methods (hepato-renal/spleno-renal section), respectively. Among them, two experienced operators were critical care clinicians, and diaphragmatic ultrasound was performed in more than 50 cases. The other two inexperienced operators were respiratory therapists, with less than 10 cases of diaphragmatic ultrasound operations, who received a 2-hour theoretical and operational training before the study. Operators initially used the conventional method with a 1.5-6.0 MHz convex probe in M-mode, placing the sampling line perpendicular to the diaphragm at the point of maximum excursion, and the liver/spleen section DE was determined during normal breathing of participant. Then, they used the novel method with a 1.6-4.5 MHz phased array probe to observe diaphragmatic movement cranio-caudally along the mid-axillary line, employing anatomic M-mode with the sampling line placed perpendicular to the diaphragm at the level of the renal midpoint, and the DE of the hepato-renal/spleno-renal section was measured during normal breathing. The liver and hepato-renal sections were used to assess the right diaphragm, and spleen and spleno-renal sections were used to assess the left diaphragm. Correlation analysis of DE measurements from different sections was conducted using the Deming method, while consistency was assessed using the Bland-Altman method. The consistency of clinical acceptability was defined as the absence of fixed and proportional bias, with a difference of two standard deviations less than 40% of the mean measurement value. Percentage consistency limit = two standard deviations of the differences between measurements/mean measurement value×100%. Four operators performed image scans of DE in all four sections for each of the twelve subjects, with a high DE acquisition rate of 100% (48/48) for hepato-renal and spleno-renal sections, followed by the liver section [91.7% (44/48)] and the spleen section [66.7% (32/48)], particularly for the left diaphragm assessment, where the DE acquisition rate of spleno-renal section was significantly higher than that of traditional spleen section (P < 0.01). The overall measurement results showed that no significant difference was found in DE determined via the hepato-renal and spleno-renal sections using the novel method (cm: 1.64±0.10 vs. 1.55±0.14, P > 0.05), and they were significantly higher than those determined via the conventional liver and spleen sections (cm: hepato-renal section vs. liver section was 1.64±0.10 vs. 1.44±0.09, spleno-renal section vs. spleen section was 1.55±0.14 vs. 1.09±0.14, both P < 0.01). Correlation analysis revealed good correlations of DE between hepato-renal section and spleno-renal section, between liver section and hepato-renal section, between liver section and spleno-renal section (r values were 0.62, 0.59, and 0.42, all P < 0.01). Consistency analysis showed that the consistency in DE between hepato-renal section and spleno-renal section, as well as between liver section and hepato-renal section was good (both % consistency limits < 40%). However, the DE measured in the spleen section were not correlated with the other three sections, and there was no inconsistency (all % consistency limits > 40%). There was no statistically significant difference in DE measured by the four operators in the liver, spleen, hepato-renal, and spleno-renal sections (cm: 1.49±0.34, 1.44±0.37, 1.43±0.30, and 1.40±0.27 in liver section; 1.10±0.36, 1.05±0.18, 1.09±0.22, and 1.06±0.26 in spleen section; 1.67±0.43, 1.57±0.34, 1.63±0.32, and 1.66±0.36 in hepato-renal section; 1.45±0.33, 1.48±0.34, 1.50±0.24, and 1.65±0.26 in spleno-renal section; all P > 0.05). According to the clinically acceptable range of consistency limits, the DE measured by the four operators in all four sections showed good consistency (all % consistency limits < 40%). The novel method of measuring DE through hepato-renal/spleno-renal sections is accurate, highly reproducible, and has a high acquisition rate, serving as a viable alternative to the conventional method involving the liver/spleen section.

Detecting Near-Surface Sub-Millimeter Voids in Additively Manufactured Ti-5V-5Al-5Mo-3Cr Alloy Using a Transmit-Receive Eddy Current Probe.

Additive Manufacturing (AM) Direct Laser Fabrication (DLF) of Ti-5Al-5V-5Mo-3Cr (Ti5553) is being developed as a method for producing aircraft components. The additive manufacturing process can produce flaws near the surface, such as porosity and material voids, which act as stress raisers, leading to potential component failure. Eddy current testing was investigated to detect flaws on or near the surface of DLF Ti5553 bar samples. For this application, the objective was to develop an eddy current probe capable of detecting flaws 500 µm in diameter, located 1 mm below the component's surface. Two initial sets of coil parameters were chosen: The first, based on successful experiments that demonstrated detection of a near surface flaw in Ti5553 using a transmit-receive array probe, and the second, derived from simulation by Finite Element Method (FEM). An optimized transmit receive coil design, based on the FEM simulations, was constructed. The probe was evaluated on Ti5553 samples containing sub-surface voids of the target size, as well as samples with side-drilled holes and samples with holes drilled from the opposing inspection surface. The probe was able to effectively detect 80% of the sub-surface voids. Limitations included the probe's inability to detect sub-surface voids near sample edges and a sensitivity to surface roughness, which produces local changes in lift-off. Multifrequency mixing improved signal-to-noise ratio when surface roughness was present on average by 22%. A probe based on that described in this paper could benefit quality assurance of additively manufactured aircraft components.

Ultrasonic convex array probe applied to increase success rate of external cephalic version without anesthesia

Objective: To explore the feasibility of using ultrasonic convex array probe compressing abdominal wall to increase success rate of external cephalic version (ECV) without anesthesia in full-term and near-term pregnancy. Methods: Totally 190 singleton and non-cephalic presentation pregnant women in 36-39+4 weeks of gestation performed ECV from April 2019 to August 2023 in the First Affiliated Hospital of Nanjing Medical University were analyzed. According to whether use the ultrasound probe compressing fetal breech or not, the pregnant women were divided into two groups: 81 cases in the probe-compressing group (including primipara 61 cases and multipara 20 cases) and 109 cases in the non-probe-compressing group(including primipara 72 cases and multipara 37 cases). Clinical data, ECV related factors and complications were analyzed and compared between the two groups. Results: (1) The overall success rate of ECV was 64.2% (122/190). There was no significant difference in the success rate of ECV between probe-compressing group and non-probe-compressing group [69.1% (56/81) vs 60.6% (66/109), χ2=1.490, P=0.222]. The total vaginal delivery rate after successful ECV was 81.1% (99/122), while 71.1% (54/76) in primipara and 97.8% (45/46) in multipara, respectively. (2) Compare to the non-probe-compressing group, the success rate of ECV in primipara was significantly higher in the probe-compressing group [45.8% (33/72) vs 70.5% (43/61)], but the gestational age was shorter and the height was higher in the probe-compressing group (all P<0.05). The success rate of ECV of multipara in the probe-compressing group (65.0%, 13/20) was lower than that in the non-probe-compressing group (89.2%, 33/37), but there was no significant difference between the two groups (P>0.05). (3) Multivariate logistic regression analysis showed that abdominal wall compressed by ultrasound probe (OR=2.601, 95%CI: 1.113-6.075; P=0.027) and amniotic fluid index (AFI; OR=1.010, 95%CI: 1.001-1.020; P=0.028) were positive factors for the successful rate of ECV in primipara pregnant women. (4) The main complication of ECV was transient fetal heart rate reduction (8.9%,17/190), the incidence in the probe-compressing group was significantly higher than that in the non-probe-compressing group [14.8% (12/81) vs 4.6% (5/109); χ2=5.967, P=0.015]. No statistical differences were found in rates of complications between the ECV successful and unsuccessful pregnant women, and between probe-compressing and non-probe-compressing groups (all P>0.05). No adverse maternal and neonatal outcomes related to ECV were observed. Conclusions: The ultrasonic convex array probe compressing could significantly improve the success rate of ECV in primipara without increasing the incidence of adverse maternal and fetal outcomes. The success rate of ECV in primipara is influenced by AFI and operation mode.

Experimental investigation of PDI bifurcation of lower hybrid waves during electron density ramp-up in EAST

The effect of parametric decay instability (PDI) on the current drive efficiency of 4.6 GHz lower hybrid (LH) waves in EAST is investigated experimentally, showing the PDI channel bifurcation of LH waves for the first time in EAST. First, experiments with three platforms of LH power were performed, achieving the LH power required for the PDI occurrence. Second, PDI bifurcation experiments were further carried out by ramping up the plasma electron density. The loop voltage increases with an increase in density, implying a decrease in the current driven by the LH wave. PDI bifurcation during electron density ramp-up was studied by analyzing the parallel refractive index ( n∥ ) and the frequency spectrum broadening, which is measured with a radio frequency magnetic probe array recently installed close to the LH antenna. It is observed for the first time that they both first increase with density, then there is not much variation and a clear sideband in the frequency spectrum is also observed when the density is up to 4×1019 m−3 , suggesting a change in the PDI channel. Calculation of the mode growth rate driven by PDI shows that when the edge electron density is up to 1.9×1018 m−3 , the growth rate of the ion cyclotron quasi-mode (ICQM) will exceed that of the ion sound quasi-mode (ISQM), quantitively explaining that with an increase in density, the PDI channel partly transits from the ISQM to the ICQM channel. Studies provide a possible way to reduce the power deposition in the edge region and improve drive capability by means of mitigating PDI behavior.

Design, Synthesis, and Biological Evaluation of Novel Nonsteroidal 18F-Labeled PET Probes Specifically Targeting Estrogen Receptor α.

The estrogen receptor α positive (ERα+) subtype represents nearly 70% of all breast cancers (BCs), which seriously threaten women's health. Positron emission computed tomography (PET) characterizes its superiority in detecting the recurrence and metastasis of BC. In this article, an array of novel PET probes ([18F]R-1, [18F]R-2, [18F]R-3, and [18F]R-4) targeting ERα based on the tetrahydropyridinyl indole scaffold were developed. Among them, [18F]R-3 and [18F]R-4 showed good target specificity toward ERα and could distinguish MCF-7 (ERα+) and MDA-MB-231 (ERα-) tumors efficiently. Especially, [18F]R-3 could differentiate the ERα positive/negative tumors successfully with a higher tumor-to-muscle uptake ratio (T/M) than that of [18F]R-4. The radioactivity of [18F]R-3 in the MCF-7 tumor was 5.24 ± 0.84%ID/mL and its T/M ratio was 2.49 ± 0.62 at 25 min postinjection, which might be the optimal imaging time point in PET scanning. On the contrary, [18F]R-3 did not accumulate in the MDA-MB-231 tumor at all. The autoradiography analysis of [18F]R-3 on the MCF-7 tumor-bearing mice model was consistent with the PET imaging results. [18F]R-3 exhibited the pharmacokinetic property of rapid distribution and slow clearance, making it suitable for use as a diagnostic PET probe. Overall, [18F]R-3 was capable of serving as a PET radiotracer to delineate the ERα+ tumor and was worthy of further exploitation.

Investigations of high-Performance Ultrasonic Transducers based on PMN-PT Single Crystals

Ultrasonic transducers for NDE applications are commonly based on Lead Zirconate Titanate or PZT, an inorganic compound and ceramic perovskite material. Until now the advantages of PMN-PT are used in medical applications, but are not implemented in NDE. Lead Magnesium Niobate-Lead Titanate (PMN-PT) is well known for its high sensitivity and broad frequency spectrum. While conventional PZT materials have an electromechanical coupling factor K33 (a measure of the conversion between electrical and acoustic energy) of about 0.72, PMN-PT materials reach peak values of more than 0.93. For applications with low signal amplitudes, high electronic noise and small transducer elements, the performance of ultrasonic probes can be significantly enhanced by using Lead Magnesium Niobate-Lead Titanate (PMN-PT) instead of PZT. This single-crystal material offers significantly better piezo parameters and leads to a higher sensitivity and larger bandwidth. There is a better depth resolution possible with this transducers as practical tests have shown. Similar to PZT it can also be fabricated in 1-3 piezo- composite technology. In a cooperation between Fraunhofer IKTS, iBULe Photonics, and IFU Diagnostic Systems, PMN-PT ultrasonic transducers are developed and optimized. The performance of phased array probes and single element transducers was measured by a so called PCUS® pro electronic front end from Fraunhofer and compared with equivalent PZT-based probes. As a result various single element and phased array transducers with im-proved performances are available for NDT of typical aerospace materials and applications. These test setups were used to weigh up the advantages and disadvantages, such as achievable precision or costs, for the implementation of a PMN-PT-based UT matrix probe. Based on this, a wiring variant adapted to the PMN-PT was developed and optimised for the matrix setups by pre- assembling the matching layers. The most favourable setup turned out to be bonding the PMN- PT composites to the prefabricated matching layers together with a rigid-flexible PCB frame. This enabled direct wire bonding of 64 matrix elements to the matching PCB pads on the rigid frame.

Fatigue crack detection in orthotropic steel deck bridges applied by FMC/TFM using reflected waves of multiple paths (1)

We introduce the latest developed FMC/TFM (Full Matrix Capture and Total Focusing Method) and its application for fatigue crack detection in orthotropic steel deck bridge. This developed inspection system consists of the advanced high-speed ultrasonic inspection equipment and the remotely operated four-wheel scanner with a 32- channel ultrasonic array probe for angle beam inspection. We developed MP-FMC/TFM (Multiple Paths Phased- array FMC/TFM) in this project. MP-FMC/TFM enables to visualize outline image of cracks clearly by image synthesis based on the propagation route information of direct path and the other paths reflected on the bottom of an inspection object against clacks. This developed inspection system enables to generate clear B-scope images of deck plate crack and bead (in deck-to-rib weld) crack with high-resolution. Furthermore, it enables to synthesizes 3D images of crack propagation with high-resolution along the weld line in real time by integrating the B-scope images every time the scanner moves 2mm. As a result of verification test of fatigue crack propagation test specimens, it was confirmed that this inspection system enables to visualize crack shape clearly and to achieves measurement accuracy of ±0.8mm for depth of deck plate crack, and ±1.0mm for depth of bead crack. Currently, verification tests are being conducted on an actual bridge, and practical application is planned in near future.

Development of a High-Frequency Mini-Convex Array Probe for Intraluminal Ultrasonic Imaging Applications

Development of a High-Frequency Mini-Convex Array Probe for Intraluminal Ultrasonic Imaging Applications

Development of an Infrared Marker based Encoder System as a Non-Contact Positioning System for Ultrasonic Probes

The digitalization of testing procedures is one of the challenges in the development of modern non-destructive testing systems. In order to guarantee a high level of inspection reliability, the assignment of measurement data to the measurement position plays an important role as well as the optimal inspection hardware. In a cooperative research and development project, an optical tracking system has been developed with which it is possible to determine the positions of different ultrasonic probes in space without contact. Thus, the position of the measurement is linked to the measurement results directly. Infrared LED markers attached to the ultrasonic probes are used for this purpose. The position of the markers are tracked in space with a camera. By linking several cameras and trackers, a positional accuracy of a few millimeters can be achieved for a camera specimen distance of 2 m. The more cameras are used the bigger the investigated part can be. For the tracking system, an existing optical camera system is coupled with a conventional of the shelve ultrasonic phased array device by means of a newly developed universal encoder. Different single transducer probes or phased array probes can be used. The costly and time consuming use of mechanical encoders is thus eliminated. This combination enables the further digitalization of hand-guided ultrasonic testing precisely in those areas where robot-based testing is not feasible. Additionally, a much easier way of documentation is possible. Due to the exact position determination a better evaluation of the measurement data can be carried out via a subsequent 3D display of the ultrasound data.

Real-Time Phased Array Ultrasonic Monitoring of Debonding Growth Under Cycling Loading in CFRP

Carbon Fibre Reinforced Polymer (CFRP) composites are widely employed in diverse industries due to their specific stiffness and strength, and corrosion resistance. However, over time, service-induced damage can initiate a failure that can threaten the operation’s safety and reliability, especially in critical industries like aerospace applications. The challenge lies in identifying and monitoring the defects before they escalate into serious issues. Non-Destructive Testing (NDT) methods play a pivotal role in this scenario, aiming to detect and evaluate defects without causing harm to the material. Detecting flaws in composite materials such as CFRP remains a complex task. Traditional NDT methods often struggle to effectively pinpoint and assess defects within these intricate structures. However, recent advancements in ultrasonic testing, especially Phased Array Ultrasonic Testing (PAUT), show promise in examining the internal composition of CFRP composites with higher accuracy and reliability. This study aims to demonstrate the applicability of PAUT for real-time monitoring of debond growth under dynamic loading. The loading was applied to the test specimens up to one million cycles, and 64 elements 2 MHz linear phased array probe was attached to the specimen. The acquired signals were analyzed and could also be recorded for offline processing or archiving. To validate the credibility of the findings, the performance of PAUT was compared to Acoustic Emission (AE), a well-established method for detecting and analysing high-frequency signals emitted by materials undergoing deformation or damage. Encouragingly, both methods exhibited similar trends in capturing the growth of debond. Furthermore, to verify the final defect lengths, post-test ultrasonic C-Scans utilizing the through transmission technique were conducted, complemented by visual inspections. These assessments served to confirm the accuracy and reliability of the results obtained through Phased Array Ultrasonic Testing. Real-time monitoring of composite structures using phased array technology comprises a valuable tool for real- time assessment of debonding in the composite. As industries continue to rely on Carbon Fibre Reinforced Polymer composites for multifaceted applications, the utilization of advanced Non-Destructive Testing methodologies like Phased Array Ultrasonic Testing emerges as a cornerstone in guaranteeing their continued integrity and performance.

3D Hybrid modeling for the ultrasonic phased array inspection of porosity in heavy plates: Simulation and experimental validation

Quantitative NDT modeling and simulation tools are important in design and fabrication of ultrasonic phased array probes with optimum characteristics and reduce the number of experimental efforts and development time. In order to achieve high accuracy (Amplitude deviation &lt; 1 dB) with a low computational time in the simulation, the modeling tools require not only the high-frequency approximation of the ultrasonic wave propagation but also the high-precision electro-acoustic coupling model. This paper describes a computationally efficient 3D time-dependent hybrid model for the simulation of ultrasonic phased array inspection of porosity in heavy plates. This method combines the results of both 3D finite element analysis (PZFLex-FEA) and the semi-analytical ultrasonic simulation “Ray-Tracing”. As a first step, we demonstrate the FEA modeling of an ultrasonic phased array probe, which includes the full 1-3 piezocomposite design with the arrangement of array elements, conducting electrodes, multi-phase backing material, acoustical matching layer and electrical circuit of a 50 Ohm coaxial cable. In the current FEA simulation, we considered the acoustical and electrical cross-talk between the adjacent elements of an ultrasonic array sensor. In the second step, the FEA-simulated ultrasonic pulse-echo signal and its frequency spectrum of an array element in the farfield region are further used as the reference input signal in the CIVA-UT software to simulate the imaging of porosity in heavy plates, quantitatively. The design of the 3D wedge-geometry of the application specific array sensor is modeled and optimized using the CIVA raytracing and multi-phase backing models. The real excitation pulse of the industrial ultrasonic testing equipment “ROMIS (ROSEN Modular Inspection System)” is also included in the simulation to achieve high accuracy in the current hybrid modeling. The dependency of the detectability of the porosity on the frequency of the array sensor and the active element group so-called “Virtual Probe” are quantitatively analyzed. Finally, the 3D hybrid model simulated Time Corrected Gain (TCG) curves of the porosity like defects in the reference steel plates are compared with the real experiments and a good quantitative agreement is achieved.