Исследование применимости при контроле дефектов высокочастотных мод направленных волн с помощью фазированных решеток

2021 ◽  
pp. 27-34
Author(s):  
М.Дж. Ранджбар ◽  
Сина Содагар
Keyword(s):  
High Frequency ◽  
Phased Array ◽  
Surface Defects ◽  
Steel Plate ◽  
Small Diameter ◽  
Guided Wave ◽  
Scanning Method ◽  
Ultrasonic Guided Wave ◽  
Array Transducer ◽  
Ultrasonic Phased Array

An ultrasonic phased array scanning method was used for lamb wave evaluation of surface and in-depth defects in a steel plate. The ultrasonic guided wave modes resulting from a phased array transducer were modeled using finite element method. The experimental results showed that the high-frequency A0 mode gives acceptable sensitivity and resolution for small diameter through-thickness and surface defects. The sectorial scanning showed better axial resolution rather than spatial resolution.

Detection of Corrosion of Insulated Piping Using SH Angle Probe

2004 ◽  
Author(s):  
Tsutomu Kikuchi ◽  
Mitoshi Yotsutsuji ◽  
Yoshikazu Yokono ◽  
Kaoru Nitta ◽  
Yasushi Takagi
Keyword(s):  
Small Diameter ◽  
Longitudinal Direction ◽  
Guided Wave ◽  
Sh Wave ◽  
Sound Beam ◽  
Surface Corrosion ◽  
Ultrasonic Guided Wave ◽  
Internal Fluid ◽  
Potential Possibility ◽  
Wave Technique

One of the serious problems regarding insulated piping in petroleum and petrochemical plants is external surface corrosion. In general, visual inspection after removing insulation is carried out to detect corrosion. However, removing insulation is uneconomical, namely high cost, and time consuming processes are necessary such as setting up a scaffold. Ultrasonic guided wave technique has potential possibility to detect corrosion of long piping and has been recently investigated regarding its propagation characteristics. In this study, guided wave generated by horizontally polarized shear (SH) wave is applied to detect corrosion of insulated piping ranging from 1B to 3B. The reason why we select SH wave is that it has an advantage of being insensitive to internal fluid in piping. Through this study it is clear that SH guided wave is applicable to small diameter piping because sound beam of SH wave propagates along the longitudinal direction without circumferential extent. Accordingly local corrosion can be detected using SH guided wave technique.

Detection of near-surface defects in rails combining Green's function retrieval of ultrasonic diffuse fields and sign coherence factor imaging

2020 ◽  
Vol 62 (4) ◽  
pp. 216-221
Author(s):  
Haiyan Zhang ◽  
Mintao Shao ◽  
Guopeng Fan ◽  
Hui Zhang ◽  
Wenfa Zhu
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Surface Defects ◽  
Signal To Noise Ratio ◽  
Near Surface ◽  
Coherence Factor ◽  
Array Transducer ◽  
Diffuse Fields ◽  
Ultrasonic Phased Array ◽  
Cross Correlations

A method combining Green's function retrieval theory and sign coherence factor (SCF) imaging is presented to detect near-surface defects in rails. The defects are close to the ultrasonic phased array and near-surface acoustic information of defects is obscured by the non-linear effects of the initial wave signal in directly acquired responses. To overcome this problem, cross-correlations of the diffuse field signals captured by the array transducer are performed to reconstruct the Green's function. SCF imaging is used to further improve the spatial resolution and signal-to-noise ratio (SNR) of near-surface defects in rails. Experiments are conducted on two rails containing two and four defects, respectively. The results show that these defects can be clearly identified when using the reconstructed Green's function. However, the images of near-surface defects are masked and cannot be distinguished when using directly captured signals and total focus imaging. The proposed method reduces the background noise and allows for effective imaging of near-surface defects in rails.

High Frequency Guided Wave Natural Focusing Pipe Inspection With Frequency and Angle Tuning

2005 ◽  
Vol 128 (3) ◽  
pp. 433-438 ◽  
Author(s):  
Li Zhang ◽  
Brian J. Gavigan ◽  
Joseph L. Rose
Keyword(s):  
High Frequency ◽  
Length Change ◽  
Guided Wave ◽  
Detection Sensitivity ◽  
Frequency Variation ◽  
Axial Distance ◽  
Focal Points ◽  
Wave Interference ◽  
Ultrasonic Guided Wave ◽  
Wave Sensitivity

When ultrasonic guided wave nondestructive evaluation is used to inspect pipelines, partial loading of transducers around the circumference leads to a non-axisymmetric energy distribution. At particular axial distances and frequencies, the ultrasonic energy is naturally focused at some spots via constructive wave interference. This so-called “natural focusing” phenomenon can be used to improve guided wave sensitivity for a defect by impinging more energy onto it. However, defects located in other places can be missed, unless we can move the natural focusing points throughout the pipe. We have done this by frequency and circumferential angle tuning for specific circumferential loading lengths. In order to utilize the natural focusing phenomenon to enhance detection sensitivity, a frequency and angle tuning (FAT) technique is employed to extend the area that can be scanned by focal energy. It is observed that the natural focal points at a fixed axial distance move with frequency variation and circumferential excitation length change. In this paper, the natural focusing phenomenon with FAT is theoretically calculated and experimentally investigated. The results show that the natural focusing inspection technique can sufficiently inspect an entire pipe with FAT.

Design of Ultrasonic Guided Wave Excitation Signal Generator for Rotating Shafts

2012 ◽  
Vol 629 ◽  
pp. 570-575
Author(s):  
Xiao Yu Wang ◽  
Yan Yan Yang ◽  
Dao Shun Wang
Keyword(s):  
Surface Defects ◽  
Wave Mode ◽  
Guided Wave ◽  
Signal Generator ◽  
Wave Excitation ◽  
Rotating Shaft ◽  
Ultrasonic Guided Wave ◽  
Detection Technology ◽  
Test Component ◽  
Rotating Shafts

Ultrasonic guided wave detection technology has mangy special characteristics. It can spread very far along the components in the distance and it can throughout the whole thickness of components, so we can make use of ultrasonic guided wave to test component of internal and surface defects. The rotating shafts are the organizations widely used in the modern production but they are very easy to be dangerous faults. If we can realize the rotating shaft in time, it can reduce the danger. It is significant to design an affordable generator which produces signals to drive magnetostrictive probe that produces ultrasonic guided wave. In this paper, we choose the torsional wave as example to design signal generator. We will introduce the way to select the appropriate guided wave mode and frequency of excitation. Design signal generator with ATmega32, AD9851 and DAC0832.

Ultrasonic Evaluation of Inclusions and Surface-Breaking Defects in High Density Polyethylene (HDPE) Butt Fusion and Mitered Joints

2015 ◽  
Author(s):  
Cliff Searfass ◽  
Jeffrey P. Milligan ◽  
Michael S. Lashley
Keyword(s):  
Numerical Modeling ◽  
Fusion Zone ◽  
High Density Polyethylene ◽  
Phased Array ◽  
High Density ◽  
Scanning Method ◽  
Empirical Results ◽  
Ultrasonic Evaluation ◽  
Ultrasonic Phased Array ◽  
Effects Of Temperature

This paper presents a method for investigating the integrity of high density polyethylene (HDPE) butt fusion joints and mitered joints. The scanning technique utilizes an ultrasonic phased array pitch-catch scanning method that provides full volumetric coverage of the fusion zone for the detection of inclusions and surface-breaking defects. Empirical results supported by numerical modeling are presented. Additionally, the effects of temperature on focalization and the proper countermeasures are discussed.

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