Lamb Wave Scattering Induced by a Rectangular Hole

2012 ◽  
Vol 166-169 ◽  
pp. 254-258
Author(s):  
Fei Long Feng ◽  
Chao Lu
Keyword(s):  
Explicit Form ◽  
Lamb Wave ◽  
Wave Scattering ◽  
Decomposition Method ◽  
Numerical Models ◽  
Scattering Matrix ◽  
Rectangular Hole ◽  
Modal Decomposition ◽  
Numerical Examples

Lamb wave scattering at a rectangular hole are investigated by using modal decomposition method. Take advantage of the biorthogonality relation, the scattering matrix is derived in an explicit form. The efficacy of the method is illustrated by numerical examples. The results are compared with those gotten from numerical models and the calculation accuracy is analyzed.

Modal Decomposition Solution of Lamb Wave Scattering at Step-Like Discontinuity

2011 ◽  
Vol 368-373 ◽  
pp. 2398-2401 ◽  
Author(s):  
Fei Long Feng ◽  
Yan Liu
Keyword(s):  
Lamb Wave ◽  
Wave Scattering ◽  
Decomposition Method ◽  
Symmetric Mode ◽  
Decomposition Technique ◽  
Modal Decomposition ◽  
Model Decomposition ◽  
Infinite Model ◽  
Different Thickness ◽  
Flux Conservation

Modal decomposition method is utilized to investigate Lamb wave scattering at step-like discontinuity. The structure is regard as a special delamination structure where one or two delamination layers are missing and only one delamination layer extended to infinite. Model decomposition technique is then combined with the boundary condition equations to get the scattering solution of the whole discontinuity region. The efficacy of the method is illustrated by calculation examples where the scattering of the second symmetric mode at step-discontinuity with different thickness are evaluated and Energy flux conservation is confirmed.

Subwavelength Defect Characterization Using Guided Wave Scattering Matrix

2013 ◽  
Vol 330 ◽  
pp. 504-509
Author(s):  
Yang Zheng ◽  
Jin Jie Zhou ◽  
Hui Zheng
Keyword(s):  
Wave Scattering ◽  
Scattering Matrix ◽  
Guided Wave ◽  
Defect Characterization ◽  
Challenging Problem ◽  
Recognition Method ◽  
Quantitative Characterization ◽  
S Matrix ◽  
Imaging Algorithms

Although many imaging algorithms such as ellipse and hyperbola algorithm can roughly locate defects in large plate-like structures with sparse guided wave arrays, quantitative characterization of them is still a challenging problem, especially for those small defects known as subwavelength defects. Scattering signals of defects contain abundant information so that can be used to evaluate defects. A defects recognition method using the S-matrix (scattering matrix) was presented. S-matrices of hole and crack with S0 mode incident were experimentally measured. The results show that defects can be recognized from the morphology of 2D S-matrix chart. This method has great potential to achieve more specific parameters of small defects with sparse guided wave arrays.

scholarly journals Modal Decomposition Method for-BWR Stability Analysis

1998 ◽  
Vol 35 (8) ◽  
pp. 538-546 ◽  
Author(s):  
G. VERDÚ ◽  
D. GINESTAR ◽  
V. VIDAL ◽  
R. MIRÓ
Keyword(s):  
Stability Analysis ◽  
Decomposition Method ◽  
Modal Decomposition

scholarly journals Lamb Wave Scattering Analysis for Interface Damage Detection between a Surface-Mounted Block and Elastic Plate

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 860
Author(s):  
Mikhail V. Golub ◽  
Alisa N. Shpak ◽  
Inka Mueller ◽  
Sergey I. Fomenko ◽  
Claus-Peter Fritzen
Keyword(s):  
Damage Detection ◽  
Elastic Plate ◽  
Lamb Wave ◽  
Wave Scattering ◽  
Hybrid Approach ◽  
Guided Wave ◽  
Open Crack ◽  
Damage Indices ◽  
Impulse Function ◽  
Thin Walled

Since stringers are often applied in engineering constructions to improve thin-walled structures’ strength, methods for damage detection at the joints between the stringer and the thin-walled structure are necessary. A 2D mathematical model was employed to simulate Lamb wave excitation and sensing via rectangular piezoelectric-wafer active transducers mounted on the surface of an elastic plate with rectangular surface-bonded obstacles (stiffeners) with interface defects. The results of a 2D simulation using the finite element method and the semi-analytical hybrid approach were validated experimentally using laser Doppler vibrometry for fully bonded and semi-debonded rectangular obstacles. A numerical analysis of fundamental Lamb wave scattering via rectangular stiffeners in different bonding states is presented. Two kinds of interfacial defects between the stiffener and the plate are considered: the partial degradation of the adhesive at the interface and an open crack. Damage indices calculated using the data obtained from a sensor are analyzed numerically. The choice of an input impulse function applied at the piezoelectric actuator is discussed from the perspective of the development of guided-wave-based structural health monitoring techniques for damage detection.

scholarly journals A New Approach for Analyzing the Reliability of the Repair Facility in a Series System with Vacations

2012 ◽  
Vol 2012 ◽  
pp. 1-16
Author(s):  
Renbin Liu ◽  
Yong Wu
Keyword(s):  
Renewal Process ◽  
Decomposition Method ◽  
Process Theory ◽  
Series System ◽  
New Approach ◽  
Numerical Examples ◽  
Special Cases ◽  
The Mean ◽  
Repair Facility

Based on the renewal process theory we develop a decomposition method to analyze the reliability of the repair facility in ann-unit series system with vacations. Using this approach, we study the unavailability and the mean replacement number during(0,t]of the repair facility. The method proposed in this work is novel and concise, which can make us see clearly the structures of the facility indices of a series system with an unreliable repair facility, two convolution relations. Special cases and numerical examples are given to show the validity of our method.

scholarly journals The Modified Sadik Decomposition Method to Solve a System of Nonlinear Fractional Volterra Integro-Differential Equations of Convolution type

2021 ◽  
Vol 20 ◽  
pp. 335-343
Author(s):  
Prapart Pue-On
Keyword(s):  
Power Series ◽  
Differential Equations ◽  
Explicit Form ◽  
Decomposition Method ◽  
Adomian Decomposition Method ◽  
Initial Solution ◽  
Convolution Type ◽  
Adomian Decomposition

In this work, an incorporated form of Sadik transform and Adomian decomposition method which is called the Sadik decomposition method is presented. The method is applied to solve a system of nonlinear fractional Volterra integro-differential equations in the convolution form. To avoid collecting the noise terms that lead the method to fail for seeking the solution, the proposed method is modified by selecting a suitable initial solution. The obtained results are expressed in the explicit form of a power series with easily computable terms. In addition, illustrative examples are shown to demonstrate the effectiveness of the method.

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