Numerical Investigation of Multi-Mode Guided Wave Focusing in Pipe\u2013Like Structures Using Gradient Index Metamaterial Lens Design

2021 ◽  
Author(s):  
Hrishikesh Danawe ◽  
Didem Ozevin ◽  
Serife Tol
Keyword(s):  
Numerical Investigation ◽  
Guided Wave ◽  
Lens Design ◽  
Gradient Index ◽  
Wave Focusing ◽  
Multi Mode

Numerical Investigation of Multi-Mode Guided Wave Focusing in Pipe–Like Structures Using Gradient Index Metamaterial Lens Design

2020 ◽  
Author(s):  
Hrishikesh G. Danawe ◽  
Didem Ozevin ◽  
Serife Tol
Keyword(s):  
Elastic Waves ◽  
Numerical Study ◽  
Guided Wave ◽  
Lens Design ◽  
Gradient Index ◽  
Focal Points ◽  
Theoretical Predictions ◽  
Multiple Frequencies ◽  
Cylindrical Steel ◽  
Multi Mode

Abstract This paper presents a numerical study on multi-mode focusing of guided elastic waves in pipe-like structures over a range of frequencies using a single metamaterial lens design. We explore focusing of the first two longitudinal (L(0,1) and L(0,2)) and the first torsional (T(0,1)) wave modes in steel pipe integrated with a metamaterial lens made of cylindrical steel stubs of varying heights attached to outer surface of the pipe. Proposed metamaterial lens design is based on gradient index (GRIN) theory with hyperbolic secant distribution of refractive index in circumferential direction. Amplification of multi-mode guided wave signals are achieved at focal points of the lens which is verified through numerical simulations. The focusing performance of proposed lens is studied at multiple frequencies for all the three modes and first two focal positions are verified with theoretical predictions of GRIN theory.

scholarly journals Passive discrete lens for broadband elastic guided wave focusing

2021 ◽  
Author(s):  
Emeline Sadoulet-Reboul ◽  
Gaël Matten ◽  
Kaijun Yi ◽  
Morvan Ouisse
Keyword(s):  
Refractive Index ◽  
Elastic Wave ◽  
Health Monitoring ◽  
Focal Point ◽  
Refractive Index Profile ◽  
Guided Wave ◽  
Gradient Index ◽  
Frequency Range ◽  
Index Profile ◽  
Wave Focusing

Elastic guided wave focusing is of great interest for applications such as vibroacoustic control, energy harvesting, or Structural Health Monitoring. Different strategies allow generation of this effect, GRadient-INdex devices in particular exploit medium with varying properties such as thickness to reproduce an adequate refractive index profile as in optics. The resulting continuous profiles have a curved geometry that can be hard to manufacture, and be difficult to integrate in a given design. The purpose of this paper is to propose a discrete design for a GRIN lens. It is composed of segments selected in number and thickness to give similar focusing effects as a continuous lens profile. The identified configuration is manufactured and bounded on an aluminium plate to evaluate the effective focusing performances. Numerical and experimental vibrometry results confirm that the proposed lens exhibits a fixed focal point over a broad frequency range. The discrete design overcomes fabrication issues encountered in continuous design, allowing for an easier integration in devices for elastic wave control.

Guided Wave Focusing Mechanics in Pipe

2003 ◽  
Author(s):  
Takahiro Hayashi ◽  
Koichiro Kawashima ◽  
Zongqi Sun ◽  
Joseph L. Rose
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Guided Waves ◽  
Wave Structure ◽  
Guided Wave ◽  
Pipe Inspection ◽  
Specific Point ◽  
Wave Focusing ◽  
Beam Focusing ◽  
Subsequent Time

Guided waves can be used in pipe inspection over long distances. Presented in this paper is a beam focusing technique to improve the S/N ratio of the reflection from a tiny defect. Focusing is accomplished by using non-axisymmetric waveforms and subsequent time delayed superposition at a specific point in a pipe. A semi-analytical finite element method is used to present wave structure in the pipe. Focusing potential is also studied with various modes and frequencies.

Ultrasonic guided wave focusing in waveguides with constant irregular cross-sections

Ultrasonics ◽  
2018 ◽  
Vol 89 ◽  
pp. 1-12 ◽  
Author(s):  
Jianjun Wu ◽  
Zhifeng Tang ◽  
Fuzai Lü ◽  
Keji Yang
Keyword(s):  
Cross Sections ◽  
Guided Wave ◽  
Wave Focusing ◽  
Ultrasonic Guided Wave

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.

Ultrasonic Flexural Torsional Guided Wave Focusing in Pipe

2004 ◽  
Author(s):  
Zongqi Sun ◽  
Joseph L. Rose
Keyword(s):  
Signal To Noise Ratio ◽  
Guided Wave ◽  
Specific Point ◽  
Wave Focusing ◽  
Focusing Effect ◽  
Wave Interference ◽  
Array Transducer ◽  
Energy Focusing ◽  
Circumferential Displacement ◽  
Wave Properties

Ultrasonic flexural torsional guided wave properties, including the excitation and propagation have been studied recently. Natural focusing is one of the major characteristics exhibited by partial loading excitation. With the aid of phased array transducer we propose a wave focusing method to enhance the signal to noise ratio and defect resolution in pipe inspection. With time delays and amplitudes applied to different elements constructive wave interference at specific point can be achieved in order to focus wave energy. Focusing effect is examined by angular profile, which is the circumferential displacement distribution.

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