Finite element analysis for the inhibition of electromagnetic acoustic testing (EMAT) Lamb waves multi-modes

This paper describes a technique, quantifying the differences in waveforms between damaged and undamaged states to measure damage severity. The technique has been verified experimentally and demonstrated promise in detecting and quantifying subsurface defects. Finite element analysis (FEA) has been performed alongside as a valid model may avoid time consuming and expensive experiments. Testing is first performed on a simple flat plate and a realistic wing skin structure with geometry such as stiffening ribs. This revealed geometry will alter the regions of scatter which leads queries over optimal sensor location. It was also discovered actuator location may not necessarily be intuitive. The comparisons made here show that implementation of an ISHM system on real world subjects is feasible despite added complexity.

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Finite-Element Analysis of Discontinuities in an Elastic Plate Waveguide for Lamb Waves and its Applications

Japanese Journal of Applied Physics ◽

10.7567/jjaps.22s3.148 ◽

1983 ◽

Vol 22 (S3) ◽

pp. 148 ◽

Cited By ~ 2

Author(s):

Masanori Koshiba ◽

Shoji Karakida ◽

Hikaru Morita ◽

Michio Suzuki

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Elastic Plate ◽

Lamb Waves ◽

Element Analysis

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Identification of delamination defects through covariance of energy change: numerical modeling

Science and Engineering of Composite Materials ◽

10.1515/secm-2014-0271 ◽

2016 ◽

Vol 23 (5) ◽

pp. 551-563

Author(s):

Taylor Bruhschwein ◽

Mijia Yang

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Numerical Modeling ◽

Fourier Transform ◽

Composite Materials ◽

Composite Laminate ◽

Lamb Waves ◽

Energy Change ◽

Element Analysis ◽

Laminate Materials

AbstractDelamination is currently a difficult detectable form of damage in composite laminate materials. This paper presents a method to more easily detect delamination damage within composite materials using finite element analysis modeling, through the covariance of energy change. Lamb waves were introduced and recorded through an actuator and sensors made of piezoelectric material. The data were then analyzed through the fast Fourier transform (FFT). Using the data from the FFT, the idea of covariance of energy change was suggested to correlate with defect characteristics. By comparing the covariance of energy change in beams with different delamination sizes, thicknesses, and depths, correlations between the covariance of energy loss and defect characteristics were able to be developed. With these correlations, the severity of these damages was able to be quantified.

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