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.

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.

A Benchmark Study of Modeling Lamb Wave Scattering by a Through Hole Using a Time-Domain Spectral Element Method

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Menglong Liu ◽  
David Schmicker ◽  
Zhongqing Su ◽  
Fangsen Cui
Keyword(s):  
Numerical Simulation ◽  
Wave Propagation ◽  
Time Domain ◽  
Lamb Wave ◽  
Spectral Element Method ◽  
Guided Waves ◽  
Three Dimensional ◽  
Spectral Element ◽  
Benchmark Study ◽  
Through Hole

Ultrasonic guided waves (GWs) are being extensively investigated and applied to nondestructive evaluation and structural health monitoring. Guided waves are, under most circumstances, excited in a frequency range up to several hundred kilohertz or megahertz for detecting defect/damage effectively. In this regard, numerical simulation using finite element analysis (FEA) offers a powerful tool to study the interaction between wave and defect/damage. Nevertheless, the simulation, based on linear/quadratic interpolation, may be inaccurate to depict the complex wave mode shape. Moreover, the mass lumping technique used in FEA for diagonalizing mass matrix in the explicit time integration may also undermine the calculation accuracy. In recognition of this, a time domain spectral element method (SEM)—a high-order FEA with Gauss–Lobatto–Legendre (GLL) node distribution and Lobatto quadrature algorithm—is studied to accurately model wave propagation. To start with, a simplified two-dimensional (2D) plane strain model of Lamb wave propagation is developed using SEM. The group velocity of the fundamental antisymmetric mode (A0) is extracted as indicator of accuracy, where SEM exhibits a trend of quick convergence rate and high calculation accuracy (0.03% error). A benchmark study of calculation accuracy and efficiency using SEM is accomplished. To further extend SEM-based simulation to interpret wave propagation in structures of complex geometry, a three-dimensional (3D) SEM model with arbitrary in-plane geometry is developed. Three-dimensional numerical simulation is conducted in which the scattering of A0 mode by a through hole is interrogated, showing a good match with experimental and analytical results.

Sign in / Sign up

Export Citation Format

Share Document