scholarly journals Reflection and transmission of Lamb waves at an imperfect joint of plates

2013 ◽  
Vol 113 (7) ◽  
pp. 074901 ◽  
Author(s):  
Naoki Mori ◽  
Shiro Biwa ◽  
Takahiro Hayashi
Keyword(s):  
Lamb Waves ◽  
Reflection And Transmission

Study of the Transmission of Ultrasonic Guided Wave at the Junction of Two Different Elastic Plates with the Presence of a Defect

2011 ◽  
Vol 482 ◽  
pp. 21-29
Author(s):  
Taoufiq Belhoussine Drissi ◽  
Bruno Morvan ◽  
Mihai Predoi ◽  
Jean Louis Izbicki ◽  
Pascal Pareige
Keyword(s):  
Lamb Waves ◽  
Guided Wave ◽  
Elastic Plates ◽  
The Finite Element Method ◽  
Reflection And Transmission ◽  
Modal Approach ◽  
Limit Value ◽  
Numerical Studies ◽  
Ultrasonic Guided Wave ◽  
Orthogonality Relations

We are interested in a right junction of two plates of different materials (aluminum and copper) placed in contact edge to edge. The aim of this study is the interaction of Lamb waves with a defect located at the junction. The reflection and transmission of the fundamental symmetrical S0 wave is analyzed. The theoretical coefficients of reflection and transmission are obtained by a multi-modal approach based on the orthogonality relations involving different modes. Using the Finite Element Method (FEM), we estimate the limit value of the ratio between the dimension of the defect and the thickness of the structure, for which the multi-modal approach is applicable. In experimental and numerical studies, it is also brought to light the effects of diffraction by the defect.

Parabolas from Reconstructed Surfaces Observed in Convergent-Beam RHEED Patterns

1990 ◽  
Vol 48 (2) ◽  
pp. 398-399
Author(s):  
M. Gajdardziska-Josifovska
Keyword(s):  
Electron Microscopy ◽  
High Energy ◽  
Two Dimensional ◽  
High Energy Electron ◽  
Reflection And Transmission ◽  
Experimental Diffraction Pattern ◽  
Surface Resonance ◽  
Reconstructed Surfaces ◽  
Reflection Electron Microscopy ◽  
Convergent Beam

Parabolas have been observed in the reflection high-energy electron diffraction (RHEED) patterns from surfaces of single crystals since the early thirties. In the last decade there has been a revival of attempts to elucidate the origin of these surface parabolas. The renewed interest stems from the need to understand the connection between the parabolas and the surface resonance (channeling) condition, the latter being routinely used to obtain higher intensity in reflection electron microscopy (REM) images of surfaces. Several rather diverging descriptions have been proposed to explain the parabolas in the reflection and transmission Kikuchi patterns. Recently we have developed an unifying general treatment in which the parabolas are shown to be K-lines of two-dimensional lattices. Here we want to review the main features of this description and present an experimental diffraction pattern from a 30° MgO (111) surface which displays parabolas that can be attributed to the surface reconstruction.

USE OF LAMB WAVES TO DETECT DAMAGE TO METAL BEAMS

2017 ◽  
Author(s):  
Anorosval Pedro Leirias da Silva Jr ◽  
Paulo Rogério Novak
Keyword(s):  
Lamb Waves
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