Advanced Composite Materials

The Korean Society for Composite Materials (한국복합재료학회)
권호 표지

Monitoring delamination of laminated CFRP using the electric potential change method (two-stage monitoring for robust estimation)

Ueda, Masahito;Todoroki, Akira;Shimamura, Yoshinobu;Kobayashi, Hideo

  • Published : 20050000
⟨ Previous Next ⟩

Abstract

Detecting delaminations of carbon fiber reinforced plastic (CFRP) laminates is a difficult task for visual inspection. Delaminations cause large reductions in strength and stiffness of CFRP laminates, bringing deterioration of the structural reliability of a CFRP. Monitoring for delamination is, therefore, indispensable to maintain the reliability of a CFRP structure. In a previous study, we adopted the electric potential change method to detect delamination. This method shows good estimation performance for delamination cracks located near the edges of a specimen, but poor performance near the center where large errors that depend on the delamination shapes are created. A zigzag delamination caused by matrix cracking has a large effect on estimation performance; so the electric potential change method was not applicable to monitoring for delamination. In this paper, a mechanism that brings large errors of estimation due to the shape of the delamination is detailed. FEM analyses show a small electric current in the thickness direction in the center segment of a specimen causes large effects on the estimation performance. The problem is overcome by means of a newly proposed concept, a two-stage method. The effectiveness of the method is demonstrated using FEM analyses.

Keywords

References

  1. K. Moriya and T. Endo, A study on flaw detection method for CFRP composite laminates (1st report), J. Jpn. Soc. for Aeronautical and Space Sci. 36 (410), 139–146 (1988).
  2. K. Schulte and C. Baron, Load and failure analyses of CFRP laminates by means of electrical resistivity measurements, Compos. Sci. Technol. 36 (1), 63–76 (1989).
  3. P.W. Chen and D. D. L. Chung, Carbon fiber reinforced concrete for smart structures capable of non-destructive flaw detection, Smart Mater. Struct. 2 (1), 22–30 (1993).
  4. P. E. Irving and C. Thiagarajan, Fatigue damage characterization in carbon fibre composite materials using an electrical potential technique, Smart Mater. Struct. 7 (4), 456–466 (1998).
  5. J. C. Abry, S. Bochard, A. Chateauminois, M. Salvia and G. Giraud, In situ detection of damage in CFRP laminates by electrical resistance measurements, Compos. Sci. Technol. 59 (6), 925–935 (1999).
  6. D. C. Seo and J. J. Lee, Damage detection of CFRP laminates using electrical resistance measurement and neural network, Composite Structures 47 (1-4), 525–530 (1999).
  7. I. Weber and P. Schwartz, Monitoring bending fatigue in carbon-fibre/epoxy composite strands: a comparison between mechanical and resistance techniques, Compos. Sci. Technol. 61 (6), 849–853 (2001).
  8. N. Muto, Y. Arai, S. G. Shin, H. Matsubara, H. Yanagida, M. Sugita and T. Nakatsuji, Hybrid composites with self-diagnosing function for preventing fatal fracture, Compos. Sci. Technol. 61 (6), 875–883 (2001).
  9. S. Kubo, M. Kuchinishi, T. Sakagami and S. Ioka, Identification of delamination in layered composite materials by the electric potential CT method, Int. J. Jpn. Soc. Appl. Electromagn. Mech. 15 (1/4), 261–267 (2001).
  10. J. B. Park, T. Okabe, N. Takeda andW. A. Curtin, Electromechanical modeling of unidirectional CFRP composites under tensile loading condition, Composites: Part A 33 (2), 267–275 (2002).
  11. C. N. Owston, Eddy current methods for the examination of carbon fibre reinforced epoxy resins, Mater. Eval. 34 (11), 237–244 (1976).
  12. T. Sakagami, S. Kubo and K. Ohji, Crack identification by the electric potential CT inverse analyses incorporating optimization techniques, Engineering Analysis with Boundary Elements 7 (2), 59–65 (1990).
  13. N. Tada, Y. Hayashi, T. Kitamura and R. Ohtani, Analysis on the applicability of direct current electrical potential method to the detection of damage by multiple small internal cracks, Int. J. Fract. 85 (1), 1–9 (1997).
  14. A. Todoroki, The effect of number of electrodes and diagnostic tool for monitoring the delamination of CFRP laminates by changes in electrical resistance, Compos. Sci. Technol. 61 (13), 1871–1880 (2001).
  15. A. Todoroki and Y. Tanaka, Delamination identification of cross-ply graphite/epoxy composite beams using electric resistance change method, Compos. Sci. Technol. 62 (5), 629–639 (2002).
  16. A. Todoroki, Y. Tanaka and Y. Shimamura, Delamination monitoring of graphite/epoxy laminated composite plate of electric resistance change method, Compos. Sci. Technol. 62 (9), 1151–1160 (2002).
  17. A. Todoroki, M. Tanaka and Y. Shimamura, Measurement of orthotropic electric conductance of CFRP laminates and analysis of the effect on delamination monitoring with an electric resistance change method, Compos. Sci. Technol. 62 (5), 619–628 (2002).
  18. A. Todoroki, M. Tanaka and Y. Shimamura, High performance estimations of delamination of graphite/epoxy laminates with electric resistance change method, Compos. Sci. Technol. 63 (13), 1911–1920 (2003).
  19. A. Todoroki, M. Tanaka, Y. Shimamura and H. Kobayashi, Analysis of the effect of the configuration of the delamination crack on delamination monitoring with electric resistance change method, J. Jpn. Soc. Compos. Mater. 29 (3), 113–119 (2003).
  20. A. Todoroki, H. Suzuki and Y. Shimamura, Identification of delamination cracks of CFRP by electrical potential method, J. Jpn. Soc. Mech. Engng (A) 65 (634), 1330–1336 (1999).
  21. A. Todoroki and H. Suzuki, Health monitoring of internal delamination cracks for graphite/epoxy composites by electric potential method, Appl. Mech. Engng 5 (1), 283–294 (2000).
  22. A. Todoroki, Y. Tanaka, Y. Shimamura and H. Kobayashi, Smart structure for detection of embedded delamination of CFRP plates using multi-point voltage change, J. Jpn. Soc. Mech. Engng (A) 67 (658), 1002–1008 (2001).
  23. M. Ueda, A. Todoroki, Y. Shimamura and H. Kobayashi, Monitoring delamination of laminated CFRP using the electric potential change method: Application of normalization method and the effect of the shape of a delamination crack, Adv. Composite Mater. 13, 311–324 (2004).
  24. R. H. Myers and D. C. Montgomery, Response Surface Methodology: Process and Product Optimization Using Designed Experiments, 2nd edn. John Wiley, New York (2002).