CONSTANT GROUP VELOCITY ULTRASONIC GUIDED WAVE INSPECTION FOR CORROSION AND EROSION MONITORING IN PIPES

2009 ◽  
Author(s):  
Geir Instanes ◽  
Audun Pedersen ◽  
Mads Toppe ◽  
Peter B. Nagy ◽  
Donald O. Thompson ◽  
...  
Keyword(s):  
Group Velocity ◽  
Guided Wave ◽  
Ultrasonic Guided Wave ◽  
Constant Group

Goodness dispersion curves for ultrasonic guided wave based SHM: a sample problem in corrosion monitoring

2010 ◽  
Vol 114 (1151) ◽  
pp. 49-56 ◽  
Author(s):  
H. Gao ◽  
J. L. Rose
Keyword(s):  
Dispersion Curve ◽  
Group Velocity ◽  
Velocity Dispersion ◽  
Group Velocity Dispersion ◽  
Mode Selection ◽  
Dispersion Curves ◽  
Guided Wave ◽  
Corrosion Monitoring ◽  
General Corrosion ◽  
Ultrasonic Guided Wave

Abstract Ultrasonic guided wave techniques have great potential for structural health monitoring applications. Appropriate mode and frequency selection is the basis for achieving optimised damage monitoring performance. In this paper, several important guided wave mode attributes are introduced in addition to the commonly used phase velocity and group velocity dispersion curves while using the general corrosion problem as an example. We first derive a simple and generic wave excitability function based on the theory of normal mode expansion and the reciprocity theorem. A sensitivity dispersion curve is formulated based on the group velocity dispersion curve. Both excitability and sensitivity dispersion curves are verified with finite element simulations. Finally, a goodness dispersion curve concept is introduced to evaluate the tradeoffs between multiple mode selection objectives based on the wave velocity, excitability and sensitivity.

Ultrasonic unilateral double-position excitation lamb wave defect detection and quantification method for ground electrode of transmission tower

2021 ◽  
pp. 1-15
Author(s):  
Kuan Ye ◽  
Kai Zhou ◽  
Ren Zhigang ◽  
Ruizhe Zhang ◽  
Chunsheng Li ◽  
...  
Keyword(s):  
Guided Waves ◽  
Power Transmission ◽  
Geometric Model ◽  
Guided Wave ◽  
Quantization Error ◽  
Dispersion Function ◽  
Stable Operation ◽  
Transmission Tower ◽  
Ultrasonic Guided Wave ◽  
Transmission Towers

The power transmission tower’s ground electrode defect will affect its normal current dispersion function and threaten the power system’s safe and stable operation and even personal safety. Aiming at the problem that the buried grounding grid is difficult to be detected, this paper proposes a method for identifying the ground electrode defects of transmission towers based on single-side multi-point excited ultrasonic guided waves. The geometric model, ultrasonic excitation model, and physical model are established, and the feasibility of ultrasonic guided wave detection is verified through the simulation and experiment. In actual inspection, it is equally important to determine the specific location of the defect. Therefore, a multi-point excitation method is proposed to determine the defect’s actual position by combining the ultrasonic guided wave signals at different excitation positions. Besides, the precise quantification of flat steel grounding electrode defects is achieved through the feature extraction-neural network method. Field test results show that, compared with the commercial double-sided excitation transducer, the single-sided excitation transducer proposed in this paper has a lower defect quantization error in defect quantification. The average quantization error is reduced by approximately 76%.

Stress measurement for steel slender waveguides based on the nonlinear relation between guided wave group velocity and stress

Measurement ◽  
2021 ◽  
pp. 109465
Author(s):  
Zuohua Li ◽  
Yingzhu Wang ◽  
Junchao Zheng ◽  
Nanxi Liu ◽  
Ming Li ◽  
...  
Keyword(s):  
Group Velocity ◽  
Stress Measurement ◽  
Guided Wave ◽  
Wave Group ◽  
Nonlinear Relation

scholarly journals Phase-delayed laser diode array allows ultrasonic guided wave mode selection and tuning

2013 ◽  
Vol 113 (14) ◽  
pp. 144904 ◽  
Author(s):  
Pasi Karppinen ◽  
Ari Salmi ◽  
Petro Moilanen ◽  
Timo Karppinen ◽  
Zuomin Zhao ◽  
...  
Keyword(s):  
Laser Diode ◽  
Mode Selection ◽  
Wave Mode ◽  
Guided Wave ◽  
Diode Array ◽  
Laser Diode Array ◽  
Ultrasonic Guided Wave

scholarly journals Rail Diagnostics Based on Ultrasonic Guided Waves: An Overview

2021 ◽  
Vol 11 (3) ◽  
pp. 1071
Author(s):  
Davide Bombarda ◽  
Giorgio Matteo Vitetta ◽  
Giovanni Ferrante
Keyword(s):  
Guided Waves ◽  
Structural Integrity ◽  
Diagnostic Procedures ◽  
Guided Wave ◽  
Rolling Stock ◽  
Technical Literature ◽  
Track Maintenance ◽  
Rail Network ◽  
Ultrasonic Guided Wave ◽  
Maintenance And Inspection

Rail tracks undergo massive stresses that can affect their structural integrity and produce rail breakage. The last phenomenon represents a serious concern for railway management authorities, since it may cause derailments and, consequently, losses of rolling stock material and lives. Therefore, the activities of track maintenance and inspection are of paramount importance. In recent years, the use of various technologies for monitoring rails and the detection of their defects has been investigated; however, despite the important progresses in this field, substantial research efforts are still required to achieve higher scanning speeds and improve the reliability of diagnostic procedures. It is expected that, in the near future, an important role in track maintenance and inspection will be played by the ultrasonic guided wave technology. In this manuscript, its use in rail track monitoring is investigated in detail; moreover, both of the main strategies investigated in the technical literature are taken into consideration. The first strategy consists of the installation of the monitoring instrumentation on board a moving test vehicle that scans the track below while running. The second strategy, instead, is based on distributing the instrumentation throughout the entire rail network, so that continuous monitoring in quasi-real-time can be obtained. In our analysis of the proposed solutions, the prototypes and the employed methods are described.

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