• Title/Summary/Keyword: Inspection of CFRP hole defects

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Variation of Eddy Current Signal According to the Defect Shape, Defect Depth and Radial Load in CFRP Tube (CFRP 튜브의 결함형상.결함깊이.레이디얼 하중에 따른 와전류 신호의 변화)

  • 송삼홍;안형근;이정순;오동준;송일;김철웅
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.12
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    • pp.2004-2011
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    • 2004
  • The applicability of the ultrasonic C-scan inspection is restricted due to the deterioration of mechanical properties of specimen during the test. Therefore, the aim of this research is applied to Eddy Current (EC) test substitute for the C-scan inspection in CFRP tube containing defects. This research is to evaluate the EC signals for the inspection of CFRP tube containing various circular hole defects (20% to 100% depth to the specimen thickness) using the unloading specimen and radial loading specimen. This study was considered the following points; 1) Analysis of EC signals for the inspection of saw-cut defect and circular hole defect, 2) The evaluation of defect depths and EC signals relationship. 3) Variation of EC signal owing to the radial load. In conclusions, the high frequency such as 300∼500 kHz made it possible to the inspection of 40% to 100% defects. Particularly, in case of 20% defect, the EC signal was not detected due to the noise of micro-crack and delamination. While the depth of the hole defects were decreasing, the difference of the phase angle between unloading specimen and radial loading specimen was gradually increasing.

Measurements of Defects after Machining CFRP Holes Using High Speed Line Scan (고속 라인 스캔 방식을 이용한 CFRP 가공 홀 표면 및 내부 결함 검사)

  • Kim, Teaggyum;Kyung, Daesu;Son, Unchul;Park, Sun-Young
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.6
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    • pp.459-467
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    • 2016
  • Using a line scan camera and a Galvano mirror, we constructed a high-speed line-scanning microscope that can generate 2D images ($8000{\times}8000pixels$) without any moving parts. The line scanner consists of a Galvano mirror and a cylindrical lens, which creates a line focus that sweeps over the sample. The measured resolutions in the x (perpendicular to line focus) and y (parallel to line focus) directions are both $2{\mu}m$, with a 2X scan lens and a 3X relay lens. This optical system is useful for measuring defects, such as spalling, chipping, delamination, etc., on the surface of carbon fiber reinforced plastic (CFRP) holes after machining in conjunction with adjustments in the angle of LED lighting. Defects on the inner wall of holes are measured by line confocal laser scanning. This confocal method will be useful for analyzing defects after CFRP machining and for fast 3D image reconstruction.