Scattering of a Small Angle Incident Acoustic Wave from a Submerged Piezoelectric Cylinder

2006 ◽  
Vol 306-308 ◽  
pp. 1229-1234 ◽  
Author(s):  
Hua Rui Liu ◽  
Jung Ju Lee
Keyword(s):  
Mathematical Model ◽  
Scattering Theory ◽  
Expansion Method ◽  
Resonance Scattering ◽  
Guided Wave ◽  
Far Field ◽  
Mode Expansion ◽  
Whispering Gallery ◽  
Field Form ◽  
Piezoelectric Constants

This paper is concerned with developing a mathematical model to describe the scattering of a plane wave obliquely incident on a piezoelectric hexagonal 6mm cylinder in a fluid. The mode is based on the normal-mode expansion method. Far-field form functions are obtained. The sensitivities of Rayleigh, Whispering Gallery, and guided wave resonances to perturbations in elastic and piezoelectric constants are discussed. The resonance scattering theory can be used for characterizing the sample in both transverse and axial directions.

Theoretical calculation of circular-crested Lamb wave field in single- and multi-layer isotropic plates using the normal mode expansion method

2019 ◽  
Vol 19 (2) ◽  
pp. 357-372 ◽  
Author(s):  
Lingfang Li ◽  
Mohammad Faisal Haider ◽  
Hanfei Mei ◽  
Victor Giurgiutiu ◽  
Yong Xia
Keyword(s):  
Wave Field ◽  
Normal Mode ◽  
Lamb Wave ◽  
Response Spectrum ◽  
Excitation Frequency ◽  
Expansion Method ◽  
Guided Wave ◽  
Element Analysis ◽  
Mode Expansion ◽  
Isotropic Plates

The guided wave technique is commonly used in the health monitoring of thin-walled structures because the guided waves can propagate far in the structures without much energy loss. However, understanding of the wave propagation in bounded layered structures is still lacking. In this study, the Lamb wave field of single- and multi-layer plates excited by surface-mounted piezoelectric wafer active sensors is theoretically analyzed using the normal mode expansion method, which is based on the elastodynamic reciprocity relation and utilizes the orthogonality relations of the Lamb wave modes. The mode participation factors of Lamb wave in single- and multi-layer isotropic plates are derived. The time domain responses are obtained through the inverse Fourier transform of the structural response spectrum, which is obtained by multiplying the transfer function with the excitation frequency spectrum. The developed normal mode expansion method is first applied to an aluminum single-layer plate. The obtained analytical tuning curves and out-of-plane velocity of the plate are in good agreement with the numerical and experimental results. Finally, the analytical wave responses of an aluminum–adhesive–steel triple-layer plate are verified through comparison with the finite element analysis and experiment. The proposed normal mode expansion method provides a reliable and accurate calculation of the wave field in single- and multi-layer plates.

scholarly journals Q-factor limits for far-field detection of whispering gallery modes in active microspheres

2015 ◽  
Vol 23 (22) ◽  
pp. 28896 ◽  
Author(s):  
Nicolas Riesen ◽  
Tess Reynolds ◽  
Alexandre François ◽  
Matthew R. Henderson ◽  
Tanya M. Monro
Keyword(s):  
Whispering Gallery Modes ◽  
Far Field ◽  
Q Factor ◽  
Field Detection ◽  
Whispering Gallery

Scattering Problems: A Variety of Topics

2012 ◽  
Author(s):  
G. F. Roach ◽  
I. G. Stratis ◽  
A. N. Yannacopoulos
Keyword(s):  
Scattering Theory ◽  
Field Operator ◽  
Optical Theorem ◽  
Perfect Conductor ◽  
Far Field ◽  
Chiral Media ◽  
Scattering Problems ◽  
Expansion Theorem ◽  
Field Patterns ◽  
Environment Problem

This chapter continues the study of scattering problems in the case where the considered fields have harmonic time dependence and the involved chiral media are homogeneous. It begins by containing various important concepts of scattering theory. Next, the chapter deals with the establishment of the reciprocity principle, the general scattering theorem, and the optical theorem for the chiral obstacle in an achiral environment problem; moreover, a study of the spectrum of the far-field operator and its relation to that of the T-matrix is included. Hereafter, the chapter deals with the generalisation of the Atkinson–Wilcox expansion theorem to the perfect conductor in a chiral environment problem and presents results on chiral Herglotz wave functions. It also exhibits infinite Fréchet differentiability of the mapping from the boundary of the scatterer onto the far-field patterns. Finally, the chapter discusses topics related to chiral media.

Butterworth Filter Application for Structural Health Monitoring

2020 ◽  
pp. 733-748
Author(s):  
Ahmed Abdelgawad ◽  
Md Anam Mahmud ◽  
Kumar Yelamarthi
Keyword(s):  
Mathematical Model ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Guided Wave ◽  
Test Bed ◽  
Explicit Finite Element ◽  
Butterworth Filter ◽  
Structural Health ◽  
Aluminum Sheets ◽  
Set Up

Most of the existing Structural Health Monitoring (SHM) systems are vulnerable to environmental and operational damages. The majority of these systems cannot detect the size and location of the damage. Guided wave techniques are widely used to detect damage in structures due to its sensitivity to different changes in the structure. Finding a mathematical model for such system will help to implement a reliable and efficient low-cost SHM system. In this paper, a mathematical model is proposed to detect the size and location of damages in physical structures using the piezoelectric sensor. The proposed model combines both pitch-catch and pulse-echo techniques and has been verified throughout simulations using ABAQUS/ Explicit finite element software. For empirical verification, data was collected from an experimental set-up using an Aluminum sheets. Since the experimental data contains a lot of noises, a Butterworth filter was used to clean up the signal. The proposed mathematical model along with the Butterworth filter have been validated throughout real test bed.

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