TY - JOUR
T1 - High-speed inspection of delamination defects in unidirectional CFRP by non-contact eddy current testing
AU - Machado, Miguel A.
AU - Antin, Kim Niklas
AU - Rosado, Luís S.
AU - Vilaça, Pedro
AU - Santos, Telmo G.
N1 - Funding Information:
MAM would like to acknowledge Fundação para a Ciência e a Tecnologia (FCT-MCTES) for its financial support via the PhD scholarship FCT-SFRH/BD/108168/2015 . TGS and MAM acknowledge FCT-MCTES for its financial support via the project UID/00667/2020 (UNIDEMI). KNA acknowledges the Swedish Cultural Foundation in Finland .
Funding Information:
MAM would like to acknowledge Funda??o para a Ci?ncia e a Tecnologia (FCT-MCTES) for its financial support via the PhD scholarship FCT-SFRH/BD/108168/2015. TGS and MAM acknowledge FCT-MCTES for its financial support via the project UID/00667/2020 (UNIDEMI). KNA acknowledges the Swedish Cultural Foundation in Finland.
Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2021/11/1
Y1 - 2021/11/1
N2 - The anisotropic bulk conductivity of carbon fibre reinforced polymers is a challenge for eddy current testing (ECT). The conductivity is markedly higher in longitudinal fibre direction compared to the transverse directions. This means that ECT has mainly been used for detecting imperfections that affect the direction and magnitude of the longitudinal conductivity. That is, fibre misalignment and broken fibres respectively. Damage in the matrix, such as delamination, affects the already low transverse bulk conductivity and is therefore very difficult to detect using ECT. A customized eddy current probe developed for detecting delamination damage in carbon fibre reinforced polymer (CFRP) composite at 4 m/s is presented in this paper. The design of the probe is based on numerical simulation of eddy current flow in the anisotropic CFRP composite. It was found that the optimal coil configuration has a current flow parallel to the conducting carbon fibres, but in two in-line coils with opposite current flow direction operating at 1 MHz frequency. This forces the eddy currents between the probes to flow perpendicular to the fibres, making the probe sensitive to changes in transverse conductivity caused by delamination. The simulated probe configuration was validated experimentally, and the constructed inspection device was able to detect real delamination damage in a CFRP component with demand for high-quality inspection.
AB - The anisotropic bulk conductivity of carbon fibre reinforced polymers is a challenge for eddy current testing (ECT). The conductivity is markedly higher in longitudinal fibre direction compared to the transverse directions. This means that ECT has mainly been used for detecting imperfections that affect the direction and magnitude of the longitudinal conductivity. That is, fibre misalignment and broken fibres respectively. Damage in the matrix, such as delamination, affects the already low transverse bulk conductivity and is therefore very difficult to detect using ECT. A customized eddy current probe developed for detecting delamination damage in carbon fibre reinforced polymer (CFRP) composite at 4 m/s is presented in this paper. The design of the probe is based on numerical simulation of eddy current flow in the anisotropic CFRP composite. It was found that the optimal coil configuration has a current flow parallel to the conducting carbon fibres, but in two in-line coils with opposite current flow direction operating at 1 MHz frequency. This forces the eddy currents between the probes to flow perpendicular to the fibres, making the probe sensitive to changes in transverse conductivity caused by delamination. The simulated probe configuration was validated experimentally, and the constructed inspection device was able to detect real delamination damage in a CFRP component with demand for high-quality inspection.
KW - Carbon fibre reinforced polymer
KW - Contactless inspection
KW - Delamination
KW - Eddy current
KW - High-speed inspection
KW - Non-destructive testing
UR - http://www.scopus.com/inward/record.url?scp=85111253018&partnerID=8YFLogxK
U2 - 10.1016/j.compositesb.2021.109167
DO - 10.1016/j.compositesb.2021.109167
M3 - Article
AN - SCOPUS:85111253018
SN - 1359-8368
VL - 224
JO - Composites Part B: Engineering
JF - Composites Part B: Engineering
M1 - 109167
ER -