Ultrasonic Phased Array Imaging Method Based On Multi - Scattering Model

this study presents an eight array ultrasonic signal phased array sparse sampling experiment system based ultrasonic phased array technology and Compressed Sensing (CS). Proposed system considers recovery ultrasonic beam signal received eight phased array elements with sparse samples captured using sub-Nyquist model in CS recovery algorithm. We have the block defect detection test in the system. The test result approximated the actual block defect position. Based on block defect detection test, We compared sparse sampling value using spectrum estimation to Compressed Sensing recovery algorithm imaging, and no focus and focus detection effect, proved the phased array experiment system based on Compressed Sensing .it can greatly improve the detection signal to noise ratio (SNR) and sensitivity. So we verify the phased array focus can improve the detection ability.

Research on the application of ultrasonic phased array detection technology has been carried out to meet the requirements for detecting defects in the bonding interface of spacecraft thermal protection suits. Spacecraft thermal protection kit specimens with pre-embedded artificial defects were prepared. Experimental research using ultrasonic phased array detection technology was conducted to achieve simulated debonding defect detection of thermal protection kit structures. Experimental results showed that ultrasonic phased array non-destructive testing technology can be applied to the non-destructive testing of the bonding interface quality of heat-resistant and aluminum alloy sleeve structures, and can achieve dimensions of effective detection of Φ15 mm debonding defects to ensure the quality and reliability of spacecraft thermal protection structures.

Defects in welds can affect the structural safety and reliability of workpieces. Currently, the method of using phased array ultrasonic inspection technology for non-destructive testing of weld structures with high detection efficiency, good sensitivity, and good visualization of the results is widely used. However, the defective A-scan data collected by the ultrasonic phased array detector inevitably contain noise data, including the test piece material structure noise, equipment noise, and environmental noise, which undoubtedly affects the analysis of the A-scan signal. In addition, when defects are interpreted, the presence of noise also interferes with the process, which affects the accuracy of the interpretation. Therefore, to enhance the accuracy of defect identification based on phased array ultrasonic inspection technology, we must prevent the series of consequences caused by misjudgments. In this study, ultrasonic phased array inspection experiments were carried out, and the specific process flow of ultrasonic phased array inspection of flat plate butt welds was summarized. Utilizing pre-fabricated flat plate butt specimen blocks containing five types of typical defects, defect A-sweep signals based on ultrasonic phased array inspection were obtained. Combining the sparrow optimization algorithm (SSA), variational mode decomposition (VMD), and wavelet packet decomposition (WPD), a defect signal noise reduction method based on parameter optimization was studied. A noise reduction study was carried out using the noise-added simulated signal, and the results indicated that the noise reduction method proposed in this paper had a better noise reduction effect and the proposed method could effectively retain the detailed features of the ultrasonic phased array defective A-scan signal and realize the noise reduction processing of the defective A-scan signal.

This paper analyzes and compares the characteristics of conventional nondestructive testing method and ultrasonic phased array testing method, and introduces several ultrasonic phased array testing methods of power grid equipment. Ultrasonic phased array technology is a high-efficiency, intuitive and reliable new nondestructive testing technology. It is of great significance to apply ultrasonic phased array technology to the nondestructive testing of power industry equipment and explore the adaptability of its testing technology to ensure the reliable operation of equipment and the security of power grid.

Welding seams are prone to safety accidents and failures during actual operation, which has an adverse effect on the economic benefits of the enterprise. When using traditional ultrasonic inspection methods to inspect the pipe butt welds, the staff needs to use the inspection probe to move as needed, which makes the inspection process difficult to operate and is greatly affected by human factors. The beam of conventional ultrasound cannot be deflected and focused. It is difficult to detect parts with complex geometric shapes and large anisotropic welds. Ultrasonic phased array is a new type of non-destructive testing method, which makes up for the limitations of conventional ultrasonic testing, and has great advantages compared with conventional ultrasound. Therefore, in order to reduce the misjudgment of defects caused by humans, this paper studies the application method of ultrasonic phased array technology in weld inspection, discusses the principles and characteristics of ultrasonic phased array inspection technology in nondestructive testing, and the defects were tested. The test results show that the phased array technology can effectively detect weld defects.

This study aims to investigate an accurate detection method to detect defects in the gasket ring groove of the blowout preventer (BOP) using the ultrasonic phased array technology. Traditionally, it is difficult to accurately determine the type and size of defects in the gasket ring groove due to the complexity of the BOP configuration and the interference between the defect echo and the structural echo when using the ultrasonic phased array detection technology. In this study, firstly, the appropriate detection process parameters are determined by using simulation software for simulating and analyzing the defects of different sizes and types in the gasket ring groove of a BOP. Thereafter, according to the detection process parameters determined by the simulation analysis, we carry out a corresponding actual detection test. Simulation analysis and detection test results show that the relative amplitude of the test results and the simulation results differ within 1 dB, and the simulation results have a guiding role for the actual detection. The defect echo and structure echo can be clearly distinguished by selecting appropriate detection process parameters, such as probe frequency 5 MHz, array elements 36, and probe aperture 16 mm. The research results can provide theoretical reference for the detection of blowout preventer.

Ultrasonic phased array has the functions of ultrasonic array, 3D imaging, and defect multi-signal characterization. However, there are problems in current detection such as effective parameter setting and inconsistent identification standards for defect characteristic signals. Based on the principle of ultrasonic phased array imaging, the experimental research on the setting of effective parameters for concrete cavity defect detection is carried out in this paper. The results show that the selection of wave velocity and frequency is the key factor to improve the accuracy of 3D imaging. For 20mm concrete cavity, when the frequency is less than 25kHz, the system cannot detect defects. When the working frequency is increased to 45KHZ, the defect imaging accuracy is gradually improved. When the frequency is increased to 60kHZ, the detection accuracy is reduced. The ultrasonic shear wave velocity is in direct proportion to the detection imaging depth. When the difference between the actual wave velocity and the set wave velocity is 10%, the influence of the detection imaging depth is small. When the difference between the actual wave velocity and the set wave velocity is greater than 20%, the detection imaging depth has a great impact, and the difference between the defect position and the actual value is too large, which may cause the system to be unable to detect the existence of defects.

The application of total focusing method (TFM) for imaging of Carbon fiber reinforced plastics (CFRP) with ultrasonic phased array is particularly challenging due to the layered structure and anisotropy of CFRP. To improve the TFM imaging performance, the precise knowledge of complex ultrasonic paths in anisotropic CFRP laminates should be obtained for accurate calculation of time of flights (TOFs), which makes the inspection process complicated and time-consuming. In this work, an adaptive TFM is developed for full-matrix imaging of CFRP laminates using ultrasonic phased array. Based on the acquired full matrix data, the elastic constants, including C 11, C 22, C 55, and C 13, can be directly derived using TOFs of A-scan signals. Based on the measured elastic constants, group velocity profiles of quasi-pressure (QP) wave were then calculated for different stacking sequences, from which the TOFs were corrected. To verify the effectiveness of proposed method, simulations and experiments are demonstrated on the CFRP laminates with different stacking sequences. As a representative example, the delamination defects are showcased. Compared with isotropic TFM, the SNR of proposed method is increased by 10.2-18.0 dB. The simulated and experimental results agreed well with each other, indicating that the feasibility of proposed method in full matrix imaging of anisotropic CFRPs.

Ultrasonic arrays are increasingly widely used in nondestructive evaluation (NDE) due to their greater flexibility and potentially superior performance compared to conventional monolithic probes. The characterization of small defects remains a challenge for NDE and is of great importance for determining the impact of a defect on the integrity of a structure. In this paper, a technique for characterizing reflectors with subwavelength dimensions is described. This is achieved by post-processing the complete data set of time traces obtained from an ultrasonic array using two algorithms. The first algorithm is used to obtain information about reflector orientation and the second algorithm is used to distinguish between point-like reflectors that reflect uniformly in all directions and specular reflectors that have distinct orientations. Experimental results are presented using a commercial 64-element, 5-MHZ array on two aluminum test specimens that contain a number of machined slots and side-drilled holes. The results show that the orientation of 1-mm-long slots can be determined to within a few degrees and that the signals from 1-mm-long slots can be distinguished from that from a 1-mm-diameter circular hole. Techniques for quantifying both the orientation and the specularity of measured signals are presented and the effect of processing parameters on the accuracy of results is discussed.

Discretized tensor-based model of total focusing method: A sparse regularization approach for enhanced ultrasonic phased array imaging

As a common welding method for polyethylene natural gas pipelines, electro-fusion welding has been widely used. However, defects are easy to occur in the fusion area during the welding. In this paper, high-density polyethylene (HDPE) pipes with different types of electric welding joint defects are processed, and the detection effect of the ultrasonic phased array on joint defects is explored. The results show that: Ultrasonic phased array detection technology is easy to operate and reliable. It can detect three common defects: inadequate socket, cold welding, and scratch of oxide scale. In addition, according to the inspection result chart, the defect type can be accurately judged.

This paper presents a systematic numerical research on ultrasonic phased array reverse time migration technique for damage evaluation in bulk materials. In this study, a thick aluminum bulk is used as the target structure to be tested, and an ultrasonic phased array composed of piezoelectric elements and damping blocks is prosed as the transducers for generating and receiving elastic waves. Firstly, a Finite Element Model (FEM) of a pair of transducers is established to study the wave generation and reception performance. In particular, the suppression effect of different backing material parameters (damping ratio, thickness, implementation details) on the piezo-elements to absorb excessive resonant vibrations is investigated, in order to send out and receive spatially squeezed mechanical pulses into the target medium. Then, a full-scale FEM is established with the complete probe set and typical structural damage types to understand the wave propagation and its interaction with damage. Both longitudinal (L) and shear (S) waves are studied, while they interact with a hole and cracks with different orientations with respect to the incident wave direction. Finally, the reverse time migration algorithm is further developed by considering the spatial wave characteristics. The amplitude variation along the propagation distance is taken into account to form a time/space-gain compensation function to improve the damage imaging quality and sensitivity, especially for far field damage sites. At the same time, the imaging algorithm is tested for the single L-wave, the single S-wave, and the fused LS-wave scenarios. It was found that the combination of L-mode and S-mode can significantly improve the damage imaging results. This numerical investigation may lay a solid foundation for the development of ultrasonic phased array technique for non-destructive evaluation (NDE) of bulky materials. This paper ends with a summary, concluding remarks, and suggestions for future work.

Ultrasonic defect detection of high-density polyethylene pipe materials using FIR filtering and block-wise singular value decomposition

This study introduces a wave-based Total Focusing Method (TFM) for ultrasonic phased array inspection, incorporating pre-recorded Time-of-Flight (ToF) values from EFIT simulations.By accurately modeling real wave propagation paths, this approach improves spatial resolution and reduces imaging artifacts.Experimental results from aluminum specimens with side-drilled holes (SDHs) demonstrate the method's superiority over conventional geometric-based TFM.

Focal laws fast calculation is one of the key technologies in ultrasonic phased array (UPA). To improve the real-time of the focal laws applied in the UPA. In the paper, we designed a focal laws calculator by FPGA technology to calculate the time delays for the ultrasonic waves between multi-element ultrasonic sensors attached a wedge and the focus to realize the beam focusing. Allowing the time delays are associated with a series of one-element higher-order equations. And n-time interval search and CORDIC algorithm are further presented for solving the equations to calculate the time delays in real time. Experiments show that the n(n=12)-time interval search and CORDIC algorithm to calculate the focal laws can achieve a maximum relative error value of 0.434% by FPGA technology. The real-time and validity of the focal laws calculator are proved through application of the UPA, which is of great importance significances in engineering application.