Hybrid local FEM/global LISA modeling of guided wave propagation and interaction with damage in composite structures

Abstract

This paper presents a hybrid modeling technique for the efficient simulation of guided wave propagation and interaction with damage in composite structures. This hybrid approach uses a local finite element model (FEM) to compute the excitability of guided waves generated by piezoelectric transducers, while the global domain wave propagation, wavedamage interaction, and boundary reflections are modeled with the local interaction simulation approach (LISA).A small-size multi-physics FEM with non-reflective boundaries (NRB) was built to obtain the excitability information of guided waves generated by the transmitter. Frequency-domain harmonic analysis was carried out to obtain the solution for all the frequencies of interest. Fourier and inverse Fourier transform and frequency domain convolution techniques are used to obtain the time domain 3-D displacement field underneath the transmitter under an arbitrary excitation. This 3-D displacement field is then fed into the highly efficient time domain LISA simulation module to compute guided wave propagation, interaction with damage, and reflections at structural boundaries. The damping effect of composite materials was considered in the modified LISA formulation. The grids for complex structures were generated using commercial FEM preprocessors and converted to LISA connectivity format. Parallelization of the global LISA solution was achieved through Compute Unified Design Architecture (CUDA) running on Graphical Processing Unit (GPU). The multi-physics local FEM can reliably capture the detailed dimensions and local dynamics of the piezoelectric transducers. The global domain LISA can accurately solve the 3-D elastodynamic wave equations in a highly efficient manner. By combining the local FEM with global LISA, the efficient and accurate simulation of guided wave structural health monitoring procedure is achieved. Two numerical case studies are presented: (1) wave propagation in a unidirectional CFRP composite plate;(2) wave propagation in a stiffened cross-ply CFRP plate with delamination.

Optimization of acousto-ultrasonic sensor networks using genetic algorithms based on experimental and numerical data sets

“…The LISA is a finite difference method which uses sharp interface modelling to solve issues regarding boundaries and discontinuities, 37 developed in the early nineties [38][39][40] for the bespoke purpose of simulating Lamb wave interaction. Since its introduction, there has been much research assessing the accuracy and reliability of models [41][42][43][44][45][46][47][48] which have been validated in experimental studies using laser vibrometry, particularly at boundaries, structural features and defects. LISA has been shown to be well suited to, and is now an established method for, modelling Lamb wave interaction.…”

Experimental Validation of Transient Spectral Finite Element Simulation Tools Dedicated to Guided Wave-Based Structural Health Monitoring

“…Recently, and thanks to the development of affordable and efficient computing hardware, especially GPUs, novel GW simulation techniques have emerged relying on intensive parallelization of mesh groups [13][14][15][16]. If these methods have shown excellent performance, with improvements of 2 to 3 orders of magnitude with respect to traditional finite element methods on CPU, they have three limitations.…”