Time-Domain Spectral Element Method for Built-In Piezoelectric-Actuator-Induced Lamb Wave Propagation Analysis

AIAA Journal ◽  
2008 ◽  
Vol 46 (3) ◽  
pp. 591-600 ◽  
Author(s):  
Yujun Kim ◽  
Sungwon Ha ◽  
Fu-Kuo Chang
Keyword(s):  
Wave Propagation ◽  
Piezoelectric Actuator ◽  
Time Domain ◽  
Lamb Wave ◽  
Spectral Element Method ◽  
Spectral Element ◽  
Propagation Analysis ◽  
Lamb Wave Propagation ◽  
Element Method

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 Wave Propagation Analysis in Composite Laminates Containing a Delamination Using a Three-Dimensional Spectral Element Method

2012 ◽  
Vol 2012 ◽  
pp. 1-19 ◽  
Author(s):  
Fucai Li ◽  
Haikuo Peng ◽  
Xuewei Sun ◽  
Jinfu Wang ◽  
Guang Meng
Keyword(s):  
Wave Propagation ◽  
Lamb Wave ◽  
Composite Laminates ◽  
Composite Structures ◽  
Spectral Element Method ◽  
Three Dimensional ◽  
Spectral Element ◽  
Wave Mode ◽  
Diagonal Form ◽  
Element Method

A three-dimensional spectral element method (SEM) was developed for analysis of Lamb wave propagation in composite laminates containing a delamination. SEM is more efficient in simulating wave propagation in structures than conventional finite element method (FEM) because of its unique diagonal form of the mass matrix. Three types of composite laminates, namely, unidirectional-ply laminates, cross-ply laminates, and angle-ply laminates are modeled using three-dimensional spectral finite elements. Wave propagation characteristics in intact composite laminates are investigated, and the effectiveness of the method is validated by comparison of the simulation results with analytical solutions based on transfer matrix method. Different Lamb wave mode interactions with delamination are evaluated, and it is demonstrated that symmetric Lamb wave mode may be insensitive to delamination at certain interfaces of laminates while the antisymmetric mode is more suited for identification of delamination in composite structures.

Wave transmission characteristics for higher-order sandwich panel with flexible core using time-domain spectral element method

2016 ◽  
Vol 19 (3) ◽  
pp. 364-393 ◽  
Author(s):  
B Raja Sekhar ◽  
S Gopalakrishnan ◽  
MVVS Murthy
Keyword(s):  
Wave Propagation ◽  
Time Domain ◽  
Spectral Element Method ◽  
Sandwich Panel ◽  
Spectral Element ◽  
Free Vibrations ◽  
Higher Order ◽  
Frequency Wave ◽  
Beam Design ◽  
Element Method

A new time-domain spectral element with nine degrees of freedom per node is formulated based on higher-order sandwich panel theory, incorporating the flexible behaviour of the core with composite face sheets. Static, free vibrations and wave propagation analysis are carried out using the formulated element. Results obtained using this element are compared with those available in the literature and with commercial finite element codes. The fast convergence of the spectral element method is demonstrated by solving the high-frequency wave propagation problem. A method of computing the wave characteristics, namely wavenumbers and group velocities, in a higher-order sandwich panel is developed using the formulated element. The effect of core damping is studied in detail with different core types, which can be used effectively in sandwich beam design.

Spectral Element Modelling of Wave Propagation and Impedance Based SHM Systems

2009 ◽  
Vol 413-414 ◽  
pp. 683-690 ◽  
Author(s):  
Rolf T. Schulte ◽  
Ke Jia Xing ◽  
Claus Peter Fritzen
Keyword(s):  
Finite Element ◽  
Wave Propagation ◽  
Time Domain ◽  
Spectral Element Method ◽  
Spectral Element ◽  
Integration Algorithm ◽  
Significant Saving ◽  
New Approach ◽  
Electromechanical Impedance ◽  
Element Method

In recent years many SHM approaches based on elastic waves that are generated and sensed by surface-bonded piezoelectric patches have been developed. Some of those utilize wave propagation phenomena; others use changes in the electromechanical impedance to detect structural damage. The capability of most approaches strongly depends on adequate choice of SHM system parameters like excitation signals and actuator/sensor types and positions. For this reason there is a growing interest in efficient and accurate simulation tools to shorten time and cost of the necessary tedious pretests. To detect small damage generally high frequency excitation signals have to be used. Because of this a very dense finite element mesh is required for an accurate simulation. As a consequence a conventional finite element simulation becomes computationally inefficient. A new approach that seems to be more promising is the time domain spectral element method. This contribution presents the theoretical background and some results of numerical calculations of the propagation of waves. The simulation is performed using the spectral element method (SEM), which leads to a diagonal mass matrix. Besides a significant saving of memory this leads to a crucial reduction of complexity of the time integration algorithm for the wave propagation calculation. A new approach to simulate the E/M impedance using time domain spectral elements is shown. An example demonstrates a good correlation of simulation and measurement data, so that the proposed simulation methodology seems to be a promising tool to make impedance based SHM systems more efficient, especially regarding the necessary parameter studies.

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