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Coating of Carbon Fibers—The Strength of the Fibers
Author(s) -
Helmer Thomas,
Peterlik Herwig,
Kromp Karl
Publication year - 1995
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1995.tb08372.x
Subject(s) - composite material , materials science , weibull distribution , fiber bundle , pyrolytic carbon , bundle , coating , fiber , linear density , weibull modulus , flexural strength , pyrolysis , mathematics , chemistry , statistics , organic chemistry
The 6k carbon fiber Torayca T800H was coated with pyrolytic carbon by a CVD process. Fiber bundles were tested and evaluated. By this procedure, the whole distribution of the failure probability with respect to the fiber strength is obtained in a single experiment. The 50% strength of the fiber bundle, i.e., the strength at which 50% of the fibers in the bundle are broken, is inversely proportional to the square root of the thickness of the coating. By relating the strength to the defect size according to linear‐elastic fracture mechanics (LEFM), the probability density function of the defects was derived. It is Weibull‐shaped for the uncoated fiber and shows an increasing bimodal shape for the increasing coating thicknesses.