A Study on Characterization for Stacking Fault Evaluation of CFRP Composite Laminates Using an EMAT Ultrasonics

전자기 초음파를 이용한 CFRP 복합적층판의 적층배향 특성평가에 관한 연구

  • Im, Kwang-Hee (Department of Automotive Engineering, Woosuk University) ;
  • Na, Seung-Woo (Division of Mechanical and Automotive Eng., Kongju University) ;
  • Kim, Ji-Hoon (Division of Mechanical Engineering, Chosun University) ;
  • Lee, Chang-Ro (Department of Automotive Engineering, Woosuk University) ;
  • Hsu, David K. (Center for Nondestructive Evaluation, Iowa State University) ;
  • Yang, In-Young (Division of Mechanical Engineering, Chosun University)
  • 임광희 (우석대학교 자동차공학과) ;
  • 나승우 (공주대학교 기계자동차공학부) ;
  • 김지훈 (조선대학교 기계설계공학과) ;
  • 이창노 (우석대학교 자동차공학과) ;
  • ;
  • 양인영 (조선대학교 기계설계학과)
  • Published : 2005.03.01

Abstract

An electromagnetic acoustic transducer (EMAT) is a unique probe that does not require a couplant or gel and also can usually generate or detect an ultrasonic wave into specimens across a small gap. It, therefore can be applied in a noncontact mode with a high degree of reproducibility. Especially stiffness of composites depends on layup sequence of CFRP(carbon fiber reinforced plastics) laminates. It is very important to evaluate the layup errors in prepreg laminates. A nondestructive technique can therefore serve as a useful measurement for detecting layup errors. This shear wave for detecting the presence of the errors is very sensitive. A decomposition model has been used in the interpretation and prediction of test results. Test results have been com pared with model data. It is found that the high probability shows between tests and the model utilized in characterizing cured layups of the laminates. Also a C-scan method was used for detecting layup of the laminates because of extracting fiber orientation information from the ultrasonic reflection caused by structural imperfections in the laminates. Therefore, it was found that interface C-scan images show the fiber orientation information by using two-dimensional fast Fourier transform (2-D FFT).

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