scholarly journals Defects Inspection in Wires by Nonlinear Ultrasonic-Guided Wave Generated by Electromagnetic Sensors

2020 ◽  
Vol 10 (13) ◽  
pp. 4479
Author(s):  
Junpil Park ◽  
Jaesun Lee ◽  
Junki Min ◽  
Younho Cho
Keyword(s):  
Guided Waves ◽  
Raw Materials ◽  
Effective Means ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Electromagnetic Acoustic Transducer ◽  
Safety Issues ◽  
Steel Wires ◽  
Nonlinear Ultrasonic ◽  
Principles Of Design

Steel wires are widely used as raw materials for spring valves in engines. Considering the quality and safety issues of their structure, there is a demand to develop nondestructive inspection approaches to detect initial damages in steel. In this study, nonlinear ultrasonic-guided waves generated by an electromagnetic acoustic transducer (EMAT) were used to inspect the defects in steel wires. As one of the noncontact testing methods, the use of EMAT has significant advantages to decrease the nonlinearity induced by instruments and transducer contact condition. The principles of design and manufacturing of EMAT are first introduced. The fundamental theory of nonlinear guided waves is also briefly discussed in this investigation. Phase-matched guided wave modes were generated and measured by using EMAT. Variations of acoustic nonlinearity corresponding to existing defects in specimens were obtained. A scanning electron microscope (SEM) was used to check the existence of microdefects in specimen. The results indicate that the use of EMAT can be an effective means to generate and measure nonlinear ultrasonic-guided waves for inspection of microdefects.

scholarly journals Nondestructive Inspection of Corrosion and Delamination at the Concrete-Steel Reinforcement Interface

2002 ◽  
Author(s):  
Tri Miller ◽  
Christopher J. Hauser ◽  
Tribikram Kundu
Keyword(s):  
Guided Waves ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Reinforcing Steel ◽  
Electromagnetic Acoustic Transducer ◽  
Long Distance ◽  
Steel Bar ◽  
Acoustic Transducer ◽  
Steel Bars ◽  
Aging Infrastructure

This paper explores the feasibility of detecting and quantifying corrosion and delamination at the interface between reinforcing steel bar and concrete using ultrasonic guided waves. The problem of corrosion and delamination of the reinforcing steel in the aging infrastructure has increased significantly in the last three decades and is likely to keep on increasing. Ultrasonic cylindrical guided waves that can propagate a long distance along the reinforcing steel bar are found to be sensitive to the interface conditions between steel bar and concrete. Ultrasonic transducers are used to launch and detect cylindrical guided waves along the steel bar. The traditional ultrasonic testing methods, for instance the pulse-echo method, where reflection, transmission, and scattering of longitudinal waves are used for detecting large voids in concrete, are not very efficient for detecting corrosion and delamination at the interface between concrete and steel bar. For this study four sets of specimens were prepared. They are rebars and plain steel bars with corrosion and physical separation. Transducers used during the experiment are the Electromagnetic Acoustic Transducer (EMAT) and the Piezoelectric Transducer (PZT). The experiment suggests that the guided wave inspection technique is feasible for the health monitoring of reinforced concrete structures. It also reveals that the ultrasonic guided waves are sensitive to the type of steel used and to the rib patterns on the reformed steel bars.

scholarly journals Numerical Simulation on Micro-damage Detection In CFRP Composites Based on Nonlinear Ultrasonic Guided Waves

2021 ◽  
Keyword(s):  
Damage Detection ◽  
Composite Structures ◽  
Guided Waves ◽  
Second Harmonic ◽  
Wave Mode ◽  
Guided Wave ◽  
Reinforced Plastics ◽  
Matrix Cracks ◽  
Nonlinear Ultrasonic ◽  
Contact Acoustic Nonlinearity

Abstract. Micro-damages such as pores, closed delamination/debonding and fiber/matrix cracks in carbon fiber reinforced plastics (CFRP) are vital factors towards the performance of composite structures, which could collapse if defects are not detected in advance. Nonlinear ultrasonic technologies, especially ones involving guided waves, have drawn increasing attention for their better sensitivity to early damages than linear acoustic ones. The combination of nonlinear acoustics and guided waves technique can promisingly provide considerable accuracy and efficiency for damage assessment and materials characterization. Herein, numerical simulations in terms of finite element method are conducted to investigate the feasibility of micro-damage detection in multi-layered CFRP plates using the second harmonic generation (SHG) of asymmetric Lamb guided wave mode. Contact acoustic nonlinearity (CAN) is introduced into the constitutive model of micro-damages in composites, which leads to the distinct SHG compared with material nonlinearity. The results suggest that the generated second order harmonics due to CAN could be received and adopted for early damage evaluation without matching the phase of the primary waves.

scholarly journals Numerical and Experimental Investigation of Guided Wave Propagation in a Multi-Wire Cable

2019 ◽  
Vol 9 (5) ◽  
pp. 1028 ◽  
Author(s):  
Pengfei Zhang ◽  
Zhifeng Tang ◽  
Fuzai Lv ◽  
Keji Yang
Keyword(s):  
Wave Energy ◽  
Guided Waves ◽  
Wave Structure ◽  
Excitation Power ◽  
Dispersion Analysis ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Mechanical Coupling ◽  
Guided Wave Propagation ◽  
Contact Acoustic Nonlinearity

Ultrasonic guided waves (UGWs) have attracted attention in the nondestructive testing and structural health monitoring (SHM) of multi-wire cables. They offer such advantages as a single measurement, wide coverage of the acoustic field, and long-range propagation ability. However, the mechanical coupling of multi-wire structures complicates the propagation behaviors of guided waves and signal interpretation. In this paper, UGW propagation in these waveguides is investigated theoretically, numerically, and experimentally from the perspective of dispersion and wave structure, contact acoustic nonlinearity (CAN), and wave energy transfer. Although the performance of all possible propagating wave modes in a multi-wire cable at different frequencies could be obtained by dispersion analysis, it is ineffective to analyze the frequency behaviors of the wave signals of a certain mode, which could be analyzed using the CAN effect. The CAN phenomenon of two mechanically coupled wires in contact was observed, which was demonstrated by numerical guided wave simulation and experiments. Additionally, the measured guided wave energy of wires located in different layers of an aluminum conductor steel-reinforced cable accords with the theoretical prediction. The model of wave energy distribution in different layers of a cable also could be used to optimize the excitation power of transducers and determine the effective monitoring range of SHM.

Nonlinear ultrasonic guided waves for stress monitoring in prestressing tendons for post-tensioned concrete structures

2009 ◽  
Author(s):  
Ivan Bartoli ◽  
Claudio Nucera ◽  
Ankit Srivastava ◽  
Salvatore Salamone ◽  
Robert Phillips ◽  
...  
Keyword(s):  
Guided Waves ◽  
Concrete Structures ◽  
Ultrasonic Guided Waves ◽  
Stress Monitoring ◽  
Nonlinear Ultrasonic ◽  
Post Tensioned

An improved design of shear horizontal guided wave electromagnetic acoustic transducer

2020 ◽  
Vol 62 (8) ◽  
pp. 494-497
Author(s):  
Xu Zhang ◽  
Sheng Feng ◽  
Jun Tu ◽  
Xiaochun Song
Keyword(s):  
Guided Waves ◽  
Cost Effective ◽  
Guided Wave ◽  
Experimental Investigations ◽  
Electromagnetic Acoustic Transducer ◽  
Rectangular Array ◽  
Acoustic Transducers ◽  
Acoustic Transducer ◽  
Improved Design ◽  
Shear Horizontal

This work proposes the use of a Halbach magnet structure to enhance the generation efficiency of shear horizontal (SH) guided waves on a plate. SH waves are normally generated using periodic permanent magnet (PPM) electromagnetic acoustic transducers (EMATs). Two PPM configurations are designed using a Halbach magnet array and the enhancements of the static magnetic fields of the two magnet arrays are validated by the finite element method, indicating that these configurations can increase the peak flux density compared with the conventional configuration. Numerical analysis and experimental investigations indicate that a racetrack coil combined with either a rectangular or triangular Halbach magnet array can enhance the amplitude of the SH guided wave by factors of ∼1.2 and ∼1.1, respectively, and that the rectangular array performs better and is more cost effective.

Ultrasonic Guided Wave Testing of Finned Tubing

2015 ◽  
Author(s):  
Owen M. Malinowski ◽  
Matthew S. Lindsey ◽  
Jason K. Van Velsor
Keyword(s):  
Wave Propagation ◽  
Guided Waves ◽  
Tube Wall ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Complex Nature ◽  
Inspection Method ◽  
Ultrasonic Guided Wave ◽  
Guided Wave Propagation ◽  
Wave Modes

In the past few decades, ultrasonic guided waves have been utilized more frequently Non-Destructive Testing (NDT); most notably, in the qualitative screening of buried piping. However, only a fraction of their potential applications in NDT have been fully realized. This is due, in part, to their complex nature, as well as the high level of expertise required to understand and utilize their propagation characteristics. The mode/frequency combinations that can be generated in a particular structure depend on geometry and material properties and are represented by the so-called dispersion curves. Although extensive research has been done in ultrasonic guided wave propagation in various geometries and materials, the treatment of ultrasonic guided wave propagation in periodic structures has received little attention. In this paper, academic aspects of ultrasonic guided wave propagation in structures with periodicity in the wave vector direction are investigated, with the practical purpose of developing an ultrasonic guided wave based inspection technique for finned tubing. Theoretical, numerical, and experimental methods are employed. The results of this investigation show excellent agreement between theory, numerical modeling, and experimentation; all of which indicate that ultrasonic guided waves will propagate coherently in finned tube only if the proper wave modes and frequencies are selected. It is shown that the frequencies at which propagating wave modes exist can be predicted theoretically and numerically, and depend strongly on the fin geometry. Furthermore, the results show that these propagating wave modes are capable of screening for and identifying the axial location of damage in the tube wall, as well as separation of the fins from the tube wall. The conclusion drawn from these results is that Guided Wave Testing (GWT) is a viable inspection method for screening finned tubing.

scholarly journals Numerical Investigation of Excitation of Various Lamb Waves Modes in Thin Plastic Films

2022 ◽  
Vol 12 (2) ◽  
pp. 849
Author(s):  
Rymantas Jonas Kazys ◽  
Justina Sestoke ◽  
Egidijus Zukauskas
Keyword(s):  
Numerical Investigation ◽  
Lamb Wave ◽  
Guided Waves ◽  
Phased Array ◽  
Ultrasonic Transducer ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Plastic Films ◽  
Thin Plastic ◽  
Wave Modes

Ultrasonic-guided waves are widely used for the non-destructive testing and material characterization of plates and thin films. In the case of thin plastic polyvinyl chloride (PVC), films up to 3.2 MHz with only two Lamb wave modes, antisymmetrical A0 and symmetrical S0, may propagate. At frequencies lower that 240 kHz, the velocity of the A0 mode becomes slower than the ultrasonic velocity in air which makes excitation and reception of such mode complicated. For excitation of both modes, we propose instead a single air-coupled ultrasonic transducer to use linear air-coupled arrays, which can be electronically readjusted to optimally excite and receive the A0 and S0 guided wave modes. The objective of this article was the numerical investigation of feasibility to excite different types of ultrasonic-guided waves, such as S0 and A0 modes in thin plastic films with the same electronically readjusted linear phased array. Three-dimensional and two-dimensional simulations of A0 and S0 Lamb wave modes using a single ultrasonic transducer and a linear phased array were performed. The obtained results clearly demonstrate feasibility to excite efficiently different guided wave modes in thin plastic films with readjusted phased array.

scholarly journals Excitation and Propagation of Longitudinal L (0, 2) Mode Ultrasonic Guided Waves for the Detection of Damages in Hexagonal Pipes: Numerical and Experimental Studies

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Xiang Wan ◽  
Meiru Liu ◽  
Xuhui Zhang ◽  
Hongwei Fan ◽  
Qinghua Mao ◽  
...  
Keyword(s):  
Guided Waves ◽  
Experimental Studies ◽  
Special Kind ◽  
Dispersion Curves ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Resource Exploitation ◽  
Ultrasonic Guided Wave ◽  
Study Results ◽  
Through Hole

The hexagonal pipe is a special kind of tube structure. Its inner surface of the cross section is in the shape of circle, while the outer surface is hexagonal. It has functioned as an essential and critical part of a drill stem in a high-torque drill machine used in various resource exploitation fields. The inspection of a hexagonal pipe to avoid its failure and thus to ensure safe operation of a drilling machine is becoming increasingly urgent and important. In this study, the excitation and propagation of ultrasonic guided waves for the purpose of detecting defects in hexagonal pipes are proposed. Dispersion curves of hexagonal pipes are firstly derived by using semianalytical finite element method. Based on these dispersion curves, longitudinal L (0, 2) mode at 100 kHz is selected to inspect hexagonal pipes. A ring of piezoelectric transducers (PZTs) with the size of 25 mm × 5 mm ×0.5 mm is able to maximize the amplitude of L (0, 2) mode and successfully suppress the undesired L (0, 1) mode in the experiments. Numerical and experimental studies have shown that the displacement field of L (0, 2) mode at 100 kHz is almost uniformly distributed along the circumferential direction. Furthermore, L (0, 2) mode ultrasonic guided waves at 100 kHz are capable of detecting circular through-hole damages located in the plane and near the edge in a hexagonal pipe. Our study results have demonstrated that the use of longitudinal L (0, 2) mode ultrasonic guided wave provides a promising and effective alternative for the detection of defects in hexagonal pipe structures.

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