Recently, thick boards of carbon-fiber-reinforced plastic (CFRP) are often used in space crafts and space structures. Nondestructive inspection (NDI) using superconducting quantum interference device (SQUID) is a prospective NDI method for the thick CFRP materials. To estimate the potential of SQUID-NDI for detection of deep-lying defects in CFRP, the skin effect must be clarified. So we applied a SQUID-NDI method to hidden slots and delaminations at various depths in thick CFRP boards to obtain the dependence of the peak amplitude of the magnetic response to the defects on the defect depth. Magnetic field response due to slots of up to 15 mm depth was detected. The response peak amplitude exponentially reduced as the depth increased. We estimated the depth dependence by a simple calculation assuming the same skin effect in CFRP as in metals. The estimated dependence differs a little from the experimental one. The difference suggests that a more accurate calculation is necessary.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering