Simulation of acoustic guided wave propagation in cortical bone using a semi-analytical finite element method

2017 ◽  
Vol 141 (4) ◽  
pp. 2538-2547 ◽  
Author(s):  
Daniel Pereira ◽  
Guillaume Haiat ◽  
Julio Fernandes ◽  
Pierre Belanger
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Wave Propagation ◽  
Cortical Bone ◽  
Guided Wave ◽  
Guided Wave Propagation ◽  
Element Method

scholarly journals Guided Wave Propagation for Monitoring the Rail Base

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Guodong Yue ◽  
Xiushi Cui ◽  
Ke Zhang ◽  
Zhan Wang ◽  
Dong An
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Wave Attenuation ◽  
Guided Wave ◽  
The Finite Element Method ◽  
Bottom Edge ◽  
Propagation Process ◽  
Guided Wave Propagation ◽  
Propagation Properties ◽  
Element Method

In order to monitor the rail base, the dispersion characteristics and propagation properties of the guided wave are studied. Firstly, two modes named as Modes V1 and V2 are selected by the semianalytical finite element method (SAFE). The region at the bottom edge can be monitored by Mode V1, while the junction of the base edge and the flange can be detected by Mode V2. Then, the characteristics in the propagation process are analyzed using the finite element method (FEM). The two modes can be separated about 0.6 ms after they are excited. Thirdly, a wave attenuation algorithm based on mean is proposed to quantify the wave attenuation. Both waves can have weak attenuation and be detected within 5 m. Finally, a mode-identified experiment is performed to validate the aforementioned analysis. And a defect detection experiment is performed to demonstrate the excellent monitoring characteristics using Mode V2. These results can be used to monitor the rail base in practice engineering.

Guided Wave Propagation Mechanics Across a Pipe Elbow

2003 ◽  
Author(s):  
Takahiro Hayashi ◽  
Koichiro Kawashima ◽  
Zongqi Sun ◽  
Joseph L. Rose
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Wave Propagation ◽  
Coordinate System ◽  
Guided Waves ◽  
Guided Wave ◽  
Cylindrical Coordinate System ◽  
Pipe Elbow ◽  
Guided Wave Propagation ◽  
Cylindrical Coordinate

Wave propagation across a pipe elbow region is complex. Subsequent reflected and transmitted waves are largely deformed due to mode conversions at the elbow. This prevents us to date from applying guided waves to the nondestructive evaluation of meandering pipeworks. Since theoretical development of guided wave propagation in a pipe is difficult, numerical modeling techniques are used. We have introduced a semi-analytical finite element method, a special modeling technique for guided wave propagation, because ordinary finite element methods require extremely long computational times and memory for such a long-range guided wave calculation. In this study, the semi-analytical finite element method for curved pipes is developed. A curved cylindrical coordinate system is used for the curved pipe region, where a curved center axis of the pipe elbow region is an axis (z′ axis) of the coordinate system, instead of the straight axis (z axis) of the cylindrical coordinate system. Guided waves in the z′ direction are described as a superposition of orthogonal functions. The calculation region is divided only in the thickness and circumferential directions. Using this calculation technique, echoes from the back wall beyond up to four elbows are discussed.

Guided Wave Propagation Mechanics Across a Pipe Elbow

2005 ◽  
Vol 127 (3) ◽  
pp. 322-327 ◽  
Author(s):  
Takahiro Hayashi ◽  
Koichiro Kawashima ◽  
Zongqi Sun ◽  
Joseph L. Rose
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Wave Propagation ◽  
Coordinate System ◽  
Guided Waves ◽  
Guided Wave ◽  
Cylindrical Coordinate System ◽  
Pipe Elbow ◽  
Guided Wave Propagation ◽  
Cylindrical Coordinate

Wave propagation across a pipe elbow region is complex. Subsequent reflected and transmitted waves are largely deformed due to mode conversions at the elbow. This prevents us to date from applying guided waves to the nondestructive evaluation of meandering pipeworks. Since theoretical development of guided wave propagation in a pipe is difficult, numerical modeling techniques are useful. We have introduced a semianalytical finite element method, a special modeling technique for guided wave propagation, because ordinary finite element methods require extremely long computational times and memory for such a long-range guided wave calculation. In this study, the semianalytical finite element method for curved pipes is developed. A curved cylindrical coordinate system is used for the curved pipe region, where a curved center axis of the pipe elbow region is an axis (z′ axis) of the coordinate system, instead of the straight axis (z axis) of the cylindrical coordinate system. Guided waves in the z′ direction are described as a superposition of orthogonal functions. The calculation region is divided only in the thickness and circumferential directions. Using this calculation technique, echoes from the back wall beyond up to four elbows are discussed.

A finite element method enriched for wave propagation problems

2012 ◽  
Vol 94-95 ◽  
pp. 1-12 ◽  
Author(s):  
Seounghyun Ham ◽  
Klaus-Jürgen Bathe
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Wave Propagation ◽  
Element Method
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