scholarly journals Numerical Time-Domain Modeling of Lamb Wave Propagation Using Elastodynamic Finite Integration Technique

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Hussein Rappel ◽  
Aghil Yousefi-Koma ◽  
Jalil Jamali ◽  
Ako Bahari
Keyword(s):  
Wave Propagation ◽  
Lamb Wave ◽  
Steel Plate ◽  
Mode Interaction ◽  
Wave Method ◽  
Integration Technique ◽  
Finite Integration Technique ◽  
Analytical Results ◽  
Lamb Wave Propagation ◽  
Element Method

This paper presents a numerical model of lamb wave propagation in a homogenous steel plate using elastodynamic finite integration technique (EFIT) as well as its validation with analytical results. Lamb wave method is a long range inspection technique which is considered to have unique future in the field of structural health monitoring. One of the main problems facing the lamb wave method is how to choose the most appropriate frequency to generate the waves for adequate transmission capable of properly propagating in the material, interfering with defects/damages, and being received in good conditions. Modern simulation tools based on numerical methods such as finite integration technique (FIT), finite element method (FEM), and boundary element method (BEM) may be used for modeling. In this paper, two sets of simulation are performed. In the first set, group velocities of lamb wave in a steel plate are obtained numerically. Results are then compared with analytical results to validate the simulation. In the second set, EFIT is employed to study fundamental symmetric mode interaction with a surface braking defect.

Modeling of Lamb Wave Propagation in Beam-Like Structures via Wavelet Finite Element Method

2016 ◽  
Author(s):  
Hao Zuo ◽  
Xuefeng Chen ◽  
Zhibo Yang ◽  
Laihao Yang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Wave Propagation ◽  
Lamb Wave ◽  
Structural Dynamic ◽  
Mode Wave ◽  
Wavelet Finite Element Method ◽  
Wavelet Finite Element ◽  
Lamb Wave Propagation ◽  
Element Method

Beam-like structure is known as one of crucial engineering structures in practical application of aerospace, vessel, civil and machinery. The damages have a great influence on machine performance and may cause a serious threat for security of mechanical structures and systems. Thus it is very significant to identify the damage of beam-like structures for security of mechanical structures and systems. This paper presents a novel application of wavelet finite element method (WFEM) in Lamb wave propagation of beam-like structures. The WFEM, adopting excellent B-spline wavelet on interval (BSWI) basis as approximating functions, has been verified to possess some superiorities for structural dynamic analysis and damage detection. The motion equations of Lamb wave propagation are derived according to Hamilton’s principle and two-dimensional wavelet-based element is constructed by adopting BSWI scaling functions. The damage, which is modeled as open crack with duplicate nodes, is considered in beam-like structures and corresponding damage model is also added in proposed wavelet finite element model. Then central difference method in time domain is employed for wave propagation simulation. Firstly, the validity and accuracy of proposed WFEM are demonstrated on a beam-like structure without crack by comparing with traditional finite element method (FEM) using 2D plane element. What’s more, the obtained velocities of fundamental S0 and A0 mode waves are also compared with Lamb theoretical results to verify the validity and accuracy of proposed model once more. Then the wave propagation in beam-like structures with crack are performed and the process and interaction between Lamb wave and damage are analyzed and discussed in detail. The reflected mode wave and converted mode wave for incident wave interacting with crack are also observed in wave motion snapshots. In summary, this paper presents an accurate but simple and effective numerical method for wave propagation of beam-like structures.

Modeling Lamb Wave Propagation in Damaged Structures Based upon Spectral Element Method

2012 ◽  
Vol 570 ◽  
pp. 79-86 ◽  
Author(s):  
Hu Sun ◽  
Li Zhou
Keyword(s):  
Wave Propagation ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Lamb Wave ◽  
Spectral Element Method ◽  
Spectral Element ◽  
Flexural Wave ◽  
Structural Health ◽  
Lamb Wave Propagation ◽  
Element Method

Structural health monitoring based on Lamb wave attracts great attention in large-span structures. Lamb wave propagation in complex structures is very complicated due to multiple reflection and mode conversion at geometrical and material features. For effectively inspecting structural integrity, numerical simulation is employed to for extract damage features. It is essential to develop fast and low-cost simulating methods to study Lamb wave propagation in damaged structures. Spectral element method (SEM) is one of the most attractive methods, which is employed to study wave propagation in damaged structures. A massless spring, coupling the longitudinal and rotational vibration, is proposed to model a transverse crack and analyze wave propagation in a composite cracked beam based on SEM. Cracked spectral element formulation is derived by modeling the crack as the spring, whose stiffness is obtained from laws of fracture mechanics. Due to asymmetry of the crack, extensional and flexural wave modes are reflected and transmitted from an incident flexural wave mode. The proposed model is verified by comparing with conventional finite element analysis. Power reflection and transmission varying with the crack depth is also calculated. The results indicate that power reflection/transmission ratio of a single mode is monotonic, which may provide some quantitative foundations for structural health monitoring.

scholarly journals Lamb wave propagation using Wave Finite Element Method

PAMM ◽  
2009 ◽  
Vol 9 (1) ◽  
pp. 509-510 ◽  
Author(s):  
Zair Asrar Bin Ahmad ◽  
Juan Miguel Vivar Perez ◽  
Christian Willberg ◽  
Ulrich Gabbert
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Wave Propagation ◽  
Lamb Wave ◽  
Lamb Wave Propagation ◽  
Element Method
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