Phased Array Technique Research Articles

Phased Array-Based Ultrasonic Testing of Explosively Welded Aluminium and Stainless Steel Plates

Phased array-based ultrasonic testing has emerged as a powerful tool in enhancing the understanding of soundness of joints, particularly for non-conventional joining techniques such as explosive welding. This technique is quite promising and provides a good co-relation between bonded and de-bonded regions in terms of different colours and varied intensities. In this paper, explosively welded stainless steel and aluminium joint was inspected with the help of phased array-based ultrasonic inspection technique. The experimental set-up as well as the inspection process using phased array technique has been discussed in detail. A-scan, B-scan and C-scan have been generated for the entire plate. The bonded regions and de-bonded area of the plate have been differentiated as well as recorded using the varied colours and their intensities in C-scans. The results of phased array confirmed the % bonded area for SS–Al combination to be more than 70%.

Imaging of Near-Surface Defects using Microwaves and Ultrasonic Phased Array Techniques

Detecting and imaging near-surface defects is of significant importance in many applications. Detecting corrosion/defects under thin paint layer applied on metallic substrates, evaluating debond under a Teflon coat, as well as evaluating the integrity of the dielectric coats remains a challenge in many industries settings. Periodic testing is imperative for a wide range of industries to isolate material defects that could lead to catastrophic failures, expensive repairs, or a complete shutdown. Out of the many non-destructive testing (NDT) techniques available, phased array ultrasonic testing (PAUT) is widely used in various industries for material inspection. It has shown exceptional capability in detection of defects, including material loss and corrosion in metals. On the other hand, near-field microwave NDT is emerging as a powerful inspection modality for similar applications. In this paper, imaging capabilities of PAUT (5 MHz) as well as near-field microwave imaging system (33.5 GHz) are discussed and evaluated for a number of specimens with man-made surface defects. The evaluated defects include flat bottom slots, holes and corrosion-under-paint. Images produced by both techniques are presented. The images produced by the microwave imaging system are benchmarked with PAUT system.

Built-In Test of Phased Arrays Using Code-Modulated Interferometry

This paper presents a built-in self-test technique for phased arrays that applies code modulation to each element within the array to allow parallel in situ measurements and a built-in distribution network to allow injection or extraction of test signals. The aggregated test response is downconverted from radio-frequency or millimeter-wave frequencies using a direct (power) detector, resulting in a baseband interference signal composed of code-modulated complex cross correlations between all elemental signals. Using orthogonal code products, each cross correlation can be extracted from the interference signal, and then the full set of cross correlations can be used to obtain amplitude and phase data of each element. A four-element 60-GHz phased-array receiver front end that includes this code-modulated embedded test (CoMET) infrastructure has been fabricated in SiGe BiCMOS technology. The BIST overhead is less than 2% of the total die area. Comparisons between our built-in test technique and measurements using a vector network analyzer show that CoMET can be used to extract amplitude with 1 dB accuracy and phase with four degree accuracy. Furthermore, measurements confirm that CoMET can be used to extract the phase-step response of each element in parallel across all settings as well as phase offset introduced by the built-in test network.

The Structure Design and Simulation of Ultrasonic Inspection Instrument for Inside Pressurized Pipe Elbows

Elbows in pressure pipes are important parts which may become serious corrosion locations. Ultrasonic detection is a main technique for pipe inner inspection, and the use of traditional ultrasound and phased array technique for in-line inspection are advanced, long-term interesting and known by researchers. Several devices were invented for inside pipeline inspection and suitable to some extent such as detecting long-distance pipelines. However, elbows especially tight elbows are still difficult to implement inner detection or travelling. To obtain good effect in detecting elbows, the inner inspection technique was investigated. Spherical and flat cylindrical probe holder structures were proposed to ensure the ability to pass through elbows, while the spherical holder has many conventional probes in its shell with a uniform distribution. The flat cylindrical probe structures are suitable for phased array ultrasonic technique to form a convex array. CIVA simulation was conducted and the focal effects were analyzed. Comparing with detecting precision and manufacture process, the phased array technique was chosen, and the elbow inspection experiments were carried out. The ultrasonic system was taken by a robot to travel through the elbow, and the experimental data were used to verify the applicability of the ultrasonic inspection technique.

基于光纤自适应操控的激光相控阵技术研究进展(特邀)

基于光纤自适应操控的激光相控阵技术研究进展(特邀)

Experimental Research on Noise Source Spectrogram of a High-speed Train’s Pantograph

Using acoustic phased array technique to take an experiment research on noise source spectrogram of a high-speed train’s Pantograph. The post-processing algorithm Non Negative Least Squares method (NNLS) is applied to deal with the initial source image obtained by traditional beamforming algorithm Day-and-Sum (DAS), and the number of iterations is chosen as 300 steps. The results of experiment show that noise of the pantograph raised is obviously larger than noise of the pantograph dropped, and the SIL of the pantograph “knuckle” facing backward is greater about 1dBA than the SIL of pantograph “knuckle” faced forward. Last, the noise source spectrogram of the pantograph raised is fitted by quadratic polynomial. According to the spectral fitting, the peak frequency is around 1.4kHz which is greater than the spectrogram of experiment. Therefore the sound energy of pantograph is mainly concentrated in the high frequency region.

Total Focusing Method or Phased Array Technique: Which Detection Technique Is Better for the Ultrasonic Nondestructive Testing of Concrete?

AbstractConcrete is a composite material composed mainly of water, sand, aggregate, and cement. The characteristics of high attenuation of concrete for ultrasound degrade the performance of ultraso...

Development toward a ground-based interferometric phased array for radio detection of high energy neutrinos

The in-ice radio interferometric phased array technique for detection of high energy neutrinos looks for Askaryan emission from neutrinos interacting in large volumes of glacial ice, and is being developed as a way to achieve a low energy threshold and a large effective volume at high energies. The technique is based on coherently summing the impulsive Askaryan signal from multiple antennas, which increases the signal-to-noise ratio for weak signals. We report here on measurements and a simulation of thermal noise correlations between nearby antennas, beamforming of impulsive signals, and a measurement of the expected improvement in trigger efficiency through the phased array technique. We also discuss the noise environment observed with an analog phased array at Summit Station, Greenland, a possible site for an interferometric phased array for radio detection of high energy neutrinos.

Опыт ультразвукового контроля аустенитных сварных соединений ЦФА- и ФАР-дефектоскопами

Опыт ультразвукового контроля аустенитных сварных соединений ЦФА- и ФАР-дефектоскопами

Excitation of leaky lamb waves in cranial bone using a phased array transducer in a concave therapeutic configuration

Ultrasonic therapeutic transducers that consist of large numbers of unfocused, low power elements have begun to replace single, focused, high power elements. This allows the operator to use phased array techniques to change the focal position in the tissue during therapy. In transcranial therapy, this phased array configuration is essential to reduce local heating at the highly attenuating bone. Recently, Dual Mode Ultrasound Arrays (DMUAs) have been developed which leverage existing elements for imaging during therapy. DMUAs have the benefit of both the therapeutic and imaging systems being co-registered. This improves upon the existing approach of using a separate ultrasound system for guidance, as the acoustic beam path is the same for both. Unfortunately, the highly reflective nature of bone means that DMUAs have not been applied to transcranial therapy. However the recent near-field observation of lamb waves in cranial bone opens the possibility for DMUAs to be applied to a guided wave scan of the skull. This would allow co-registration of the bone’s ultrasonic properties with the therapeutic axis which would facilitate adaptive beamforming. In this work, a beamforming scheme for the excitation of guided waves in cranial bone using a therapeutic phased array is described and demonstrated experimentally.

A 94-GHz 4TX–4RX Phased-Array FMCW Radar Transceiver With Antenna-in-Package

A 94-GHz phased-array transceiver IC for frequency modulated continuous wave (FMCW) radar with four transmitters, four receivers, and integrated LO generation has been designed and fabricated in a 130-nm SiGe BiCMOS technology, and integrated into an antenna-in-package module. The transceiver, targeting gesture recognition applications for mobile devices, has been designed using phased-array techniques to reduce the total DC power while still maintaining the required link budget for FMCW operation. The complete array achieves state-of-the-art for W-band per-element power consumption of 106 mW per TX element and 91 mW per RX element, and measurements indicate a per-element output power of 6.4 dBm and single-sideband noise figure of 12.5 dB at 94 GHz. The array is able to achieve a beam steering range of ±20° while maintaining at least 3 dB main lobe to side lobe levels. The complete chip-antenna module has been tested to characterize basic FMCW radar functionality. Initial radar experiments suggest a sub-5-cm range resolution is possible with 3.68 GHz RF sweep bandwidth, which is in line with theoretical predictions.

Ultrasound imaging of immersed plates using high-order Lamb modes at their low attenuation frequency bands

This paper focuses on the use of a Lamb wave-based methodology for ultrasound imaging of immersed plate structures. In these cases Lamb waves can be strongly attenuated due to leaky waves and viscous losses in the liquid, but there are low attenuation frequency bands that may be used for NDT applications. Experimental measurements were conducted to validate the existence of these low attenuation frequency bands, which were also theoretically predicted for some propagation modes, between the frequencies-thickness products of 0.5MHzmm and 9.0MHzmm. Using a 5MHz linear-array and phased-array techniques, A1 and S1 modes are used to obtain images of an immersed aluminum plate with artificial defects. The signals are post-processed in order to select the desired propagation mode and to obtain an image with dynamic focusing in reception. While the A1 mode is strongly attenuated, the S1 mode, at 3.4MHzmm, can be used to detect and localize defects in the immersed plate.

Phased Array Ultrasound System for Planar Flow Mapping in Liquid Metals.

Controllable magnetic fields can be used to optimize flows in technical and industrial processes involving liquid metals in order to improve quality and yield. However, experimental studies in magnetohydrodynamics often involve complex, turbulent flows and require planar, two-component (2c) velocity measurements through only one acoustical access. We present the phased array ultrasound Doppler velocimeter as a modular research platform for flow mapping in liquid metals. It combines the pulse wave Doppler method with the phased array technique to adaptively focus the ultrasound beam. This makes it possible to resolve smaller flow structures in planar measurements compared with fixed-beam sensors and enables 2c flow mapping with only one acoustical access via the cross beam technique. From simultaneously measured 2-D velocity fields, quantities for turbulence characterization can be derived. The capabilities of this measurement system are demonstrated through measurements in the alloy gallium-indium-tin at room temperature. The 2-D, 2c velocity measurements of a flow in a cubic vessel driven by a rotating magnetic field (RMF) with a spatial resolution of up to 2.2 mm are presented. The measurement results are in good agreement with a semianalytical simulation. As a highlight, two-point correlation functions of the velocity field for different magnitudes of the RMF are presented.

Compressive sensing of phased array ultrasonic signal in defect detection: Simulation study and experimental verification

Ultrasonic phased array techniques are widely used for defect detection in structural health monitoring field. The increase in the element number, however, leads to larger amounts of data acquired and processed. Recently developed compressive sensing states that sparse signals may be accurately recovered from far fewer measurements, suggesting the possibility of breaking through the sampling limit of the Nyquist theorem. In light of this significant advantage, the novel use of the compressive sensing methodology for ultrasonic phased array in defect detection is proposed in this work. Based on CIVA software, we first present a simulated study on the effectiveness of the compressive sensing applied in ultrasonic phased array in defect detection through the average mean percent residual difference at varying compression rates. The results particularly show that the compressive sensing yields a breakthrough of the sampling limitation. We then experimentally demonstrate comparative analyses on the signals extracted from three types of artificial flaws (through-hole, flat-bottom hole, and electrical discharge machining notches) on two different specimens (made of aluminum and 20# steel). To find the optimal algorithm combination, the best sparse representation basis is chosen among fast Fourier transform, discrete cosine transform, and 34 wavelet kernels; the reconstruction performance is compared between five greedy algorithms; and the recovery accuracy is further improved via four sensing matrices selection. We also evaluate the influence of the sampling rate, and our results are comparable with the gold standard of signal compression, namely, the discrete wavelet transform.

Identifying equivalent sound sources from aeroacoustic simulations using a numerical phased array

An application of phased array methods to numerical data is presented, aimed at identifying equivalent flow sound sources from aeroacoustic simulations. Based on phased array data extracted from compressible flow simulations, sound source strengths are computed on a set of points in the source region using phased array techniques assuming monopole propagation. Two phased array techniques are used to compute the source strengths: an approach using a Moore-Penrose pseudo-inverse and a beamforming approach using dual linear programming (dual-LP) deconvolution. The first approach gives a model of correlated sources for the acoustic field generated from the flow expressed in a matrix of cross- and auto-power spectral values, whereas the second approach results in a model of uncorrelated sources expressed in a vector of auto-power spectral values. The accuracy of the equivalent source model is estimated by computing the acoustic spectrum at a far-field observer. The approach is tested first on an analytical case with known point sources. It is then applied to the example of the flow around a submerged air inlet. The far-field spectra obtained from the source models for two different flow conditions are in good agreement with the spectra obtained with a Ffowcs Williams-Hawkings integral, showing the accuracy of the source model from the observer's standpoint. Various configurations for the phased array and for the sources are used. The dual-LP beamforming approach shows better robustness to changes in the number of probes and sources than the pseudo-inverse approach. The good results obtained with this simulation case demonstrate the potential of the phased array approach as a modelling tool for aeroacoustic simulations.

Focused ultrasound treatment for central nervous system disease: neurosurgeon's perspectives.

The concept of focused ultrasound (FUS) and its application in the field of medicine have been suggested since the mid-20th century. However, the clinical applications of this technique in central nervous system (CNS) diseases have been extremely limited because the skull inhibits efficient energy transmission. Therefore, early application of FUS treatment was only performed in patients who had already undergone invasive procedures including craniectomy and burr hole trephination. In the 1990s, the phased array technique was developed and this enabled the focus of ultrasonic energy through the skull, and in conjunction with another technique, magnetic resonance thermal monitoring, the possibility of applying FUS in the CNS was further strengthened. The first clinical trial using FUS treatment for CNS diseases was performed in the early 21st century in patients with glioblastoma, which consists of highly malignant primary brain tumors. However, this trial resulted in a failure to make lesions in the tumors. Various causes were suggested for this outcome including different acoustic impedances across heterogeneous intracranial tissue (not only brain tissue, but also fibrous or tumor tissue). To avoid the influence of this factor, the targets for FUS treatment were shifted to functional diseases such as essential tremor, Parkinson's disease, and psychiatric disease, which usually occur in normal brain structures. The first trial for functional diseases was started in 2010, and the results were successful as accurate lesions were made in the target area. Nowadays, the indication of FUS treatment for functional CNS diseases is gradually widening, and many trials using the FUS technique are reporting good results. In addition to the lesioning technique using high intensity FUS treatment, the possibility of clinical application of low intensity FUS to CNS disease treatment has been investigated at a pre-clinical level, and it is expected that FUS treatment will become one of the most important novel techniques for the treatment of CNS diseases in the near future.

Capacitive imaging of impact damage in composite material

Abstract This work presents capacitive non-destructive imaging of impact damage in woven fibre CFRP using a coplanar capacitive sensor. Novelty of the approach consists in that spectral characteristics of the capacitive sensor response to CFRP properties are firstly used to establish excitation frequencies for optimum imaging of delamination. For the tested samples optimum excitation frequencies were found to be above 200 MHz. Clear capacitive images of delaminations were obtained on each sample. Ultrasonic (UT) C-scans of delaminations due to impacts were acquired using phased array technique to confirm presence and extent of the delaminations. Capacitive imaging technique can be used as complementary to UT for imaging shallow defects in composite materials at depths where UT has insufficient time domain resolution.

КОНТРОЛЬ ДЕТАЛЕЙ И КОНСТРУКЦИЙ ИЗ ПОЛИМЕРНЫХ КОМПОЗИЦИОННЫХ МАТЕРИАЛОВ С ПРИМЕНЕНИЕМ ТЕХНОЛОГИИ УЛЬТРАЗВУКОВЫХ ФАЗИРОВАННЫХ РЕШЕТОК

КОНТРОЛЬ ДЕТАЛЕЙ И КОНСТРУКЦИЙ ИЗ ПОЛИМЕРНЫХ КОМПОЗИЦИОННЫХ МАТЕРИАЛОВ С ПРИМЕНЕНИЕМ ТЕХНОЛОГИИ УЛЬТРАЗВУКОВЫХ ФАЗИРОВАННЫХ РЕШЕТОК

Experimental Study on Rapid Repair of Foam Sandwich Composites for Radome with Low-velocity Impact Damage

Sandwich structure composites are commonly used in Radar radomes, the core materials mainly include honeycomb material and foam material. Impact damage is the greatest threat to this kind of structure. In this paper, low-velocity impact damage was simulated by drop hammer test, while ultrasonic phased array technique was used as NDT(Non-Destructive Testing Technology), and restored by scarf repair technique. The mechanical properties and the electromagnetic wave performance of the foam sandwich panel before and after repair were carried out comparatively. The results show that, the flexural strength can restore 112.7% of the undamaged plate, and the lateral compressive strength can restore 85.1%. The repair efficiency calculated from tests was observed to be 135% and 50.7% respectively. Besides, electro-magnetic wave permeability was improved apparently. The method for repairing the low-velocity impact damage of the foam sandwich structure can meet the requirements of the rapid repair for practical radome structure.

A synchronous serial bus for multidimensional array acoustic logging tool

In high-temperature and spatial borehole applications, a distributed structure is employed in a multidimensional array acoustic logging tool (MDALT) based on a phased array technique for electronic systems. However, new challenges, such as synchronous multichannel data acquisition, multinode real-time control and bulk data transmission in a limited interval, have emerged. To address these challenges, we developed a synchronous serial bus (SSB) in this study. SSB works in a half-duplex mode via a master–slave architecture. It also consists of a single master, several slaves, a differential clock line and a differential data line. The clock line is simplex, whereas the data line is half-duplex and synchronous to the clock line. A reliable communication between the master and the slaves with real-time adjustment of synchronisation is achieved by rationally designing the frame format and protocol of communication and by introducing a scramble code and a Hamming error-correcting code. The control logic of the master and the slaves is realized in field programmable gate array (FPGA) or complex programmable logic device (CPLD). The clock speed of SSB is 10 MHz, the effective data rate of the bulk data transmission is over 99%, and the synchronous errors amongst the slaves are less than 10 ns. Room-temperature test, high-temperature test (175 °C) and field test demonstrate that the proposed SSB is qualified for MDALT.