Non-destructive evaluation (NDE) of composites: eddy current techniques

Heuer, Henning; Schulze, Martin; Meyendorf, Norbert

doi:10.1533/9780857093554.1.33

Cited by 30 publications

(25 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This was later expanded for use on 2D raster-scan ECT data by performing 2D fast Fourier transforms (2D-FFTs) [15]. This analysis approach has been widely adopted for automated in-process monitoring of fibre alignment [16,17,18,19,20]. However, 2D-FFT analysis is an inherently Cartesian transform making the accurate extraction of angular information an inelegant secondary process requiring careful correction to remain universally valid.…”

Section: Ply Orientationmentioning

confidence: 99%

Characterisation of carbon fibre-reinforced polymer composites through radon-transform analysis of complex eddy-current data

Hughes

Drinkwater

Smith

2018

Composites Part B: Engineering

View full text Add to dashboard Cite

Maintaining the correct fibre orientations and stacking sequence in carbon-fibre reinforced polymers (CFRP) during manufacture is essential for achieving the required mechanical properties of a component. This paper presents and evaluates a method for the rapid characterisation of the fibre orientations present in CFRP structures, and the differentiation of different stacking sequences, through the Radon-transform analysis of complex-valued eddy-current testing (ECT) inspection data. A high-frequency (20 MHz) eddy-current inspection system was used to obtain 2D scans of a range of CFRP samples of differing ply stacking sequences. The complex electrical impedance scan data was analysed using Radon-transform techniques to quickly and simply determine the dominant fibre orientations present in the structure. This method is compared to 2D-fast Fourier transform (2D-FFT) analysis of the same data and shown to give superior quantitative results with comparatively fewer computational steps and corrections. Further analysis is presented demonstrating and examining a method for preserving the complex information inherent within the eddycurrent scan data during Radon-transform analysis. This investigation shows that the real and imaginary components of the ECT data encode information about the sacking sequence allowing the distinction between composites with different stacking structures. This new analysis technique could be used for in-process analysis of CFRP structures as a more accurate characterisation method, reducing the chance of costly manufacturing errors.

show abstract

Section: Ply Orientationmentioning

confidence: 99%

Characterisation of carbon fibre-reinforced polymer composites through radon-transform analysis of complex eddy-current data

Hughes

Drinkwater

Smith

2018

Composites Part B: Engineering

View full text Add to dashboard Cite

show abstract

“…The alternating current in the coil induces an alternating magnetic field in the element which causes the flow of eddy currents. Thickness changes or flaws in the test element influence the flow of eddy currents and change the impedance of the coil [10,13]. Eddy current testing is particularly well-suited for detection of service-induced cracks [10], but also corrosion, surface breakings [3,10], missing carbon fibre bundles [13], porosity, voids and foreign inclusions [20].…”

Section: Eddy Current Inspectionmentioning

confidence: 99%

A Brief Review on NDT&E Methods For Structural Aircraft Components

Wronkowicz-Katunin

2018

Fatigue of Aircraft Structures

View full text Add to dashboard Cite

The paper presents a summary of non-destructive testing and evaluation (NDT&E) methods applied in inspections of structural aircraft components. This brief review covers the most commonly applied methods such as visual and penetrant inspections, tap-testing, eddy current inspections, shearography, thermography, acoustic emission testing, radiographic and tomographic inspections, and ultrasonic inspections. The general operating principles of these methods as well as their main advantages, limitations and application areas are described below.

show abstract

“…Eddy current (EC) technology is a well-established nondestructive method for the characterization of surfaces or materials by analyzing conductivity and permeability variations [2]. A primary magnetic field is generated when an alternating current is applied to an induction coil.…”

Section: Radio Frequency Inspectionmentioning

confidence: 99%

“…The modulation of the signal amplitude as a function of the depth of an out-of-plane wave can be explained by formula (1) and (2). The eddy current density decays exponentially with increasing depth.…”

Section: Characterization Of Defects According To Their Depthmentioning

confidence: 99%

Review on quality assurance along the CFRP value chain – Non-destructive testing of fabrics, preforms and CFRP by HF radio wave techniques

Heuer

Schulze

Pooch

et al. 2015

Composites Part B: Engineering

Self Cite

139

View full text Add to dashboard Cite

a b s t r a c tEddy current testing is well established for non-destructive testing of electrical conductive materials [1]. The development of radio frequency (RF) eddy current technology with frequency ranges up to 100 MHz made it possible to extend the classical fields of application even towards less conductive materials like CFRP [2][3]( Table 2). It turns out that RF eddy current technology on CFRP generates a growing number of valuable information for comprehensive material diagnostic. Both permittivity and conductivity of CFRP influence the complex impedance measured with RF eddy current devices. The electrical conductivity contains information about fiber texture like orientations, gaps or undulations in a multilayered material. The permittivity characterization influenced by dielectric properties allows the determination of local curing defects on CFRP e.g. hot spots, thermal impacts or polymer degradation. An explanation for that effect is seen in the measurement frequency range and the capacitive structure of the carbon rovings. Using radio wave frequencies for testing, the effect of displacement currents cannot be neglected anymore. The capacitive structures formed by the carbon rovings is supposed to further strengthen the dielectric influences on eddy current measurement signal [3]. This report gives an overview of several realized applications and should be understood as a general introduction of CFRP testing by HF Radio Wave techniques.

show abstract

Non-destructive evaluation (NDE) of composites: eddy current techniques

Cited by 30 publications

References 5 publications

Characterisation of carbon fibre-reinforced polymer composites through radon-transform analysis of complex eddy-current data

Characterisation of carbon fibre-reinforced polymer composites through radon-transform analysis of complex eddy-current data

A Brief Review on NDT&E Methods For Structural Aircraft Components

Review on quality assurance along the CFRP value chain – Non-destructive testing of fabrics, preforms and CFRP by HF radio wave techniques

Contact Info

Product

Resources

About