Fiber pull-out is one of the failure mechanisms in fiber-reinforced composite materials. Other forms of failure include delamination, intralaminar matrix cracking, longitudinal matrix splitting, fiber/matrix debonding, and fiber fracture. The cause of fiber pull-out and delamination is weak bonding.Serope Kalpakjian, Steven R Schmid. "Manufacturing Engineering and Technology". 6th Ed. Prentice Hall, Inc. 2009, p. 223.
Work for debonding, PWR Beaumont. "Fracture mechanisms in fibrous composites". Fracture Mechanics, Current Status, Future Prospects. Edited by RA Smith. Pergamon Press: 1979. p211-33 in
where is fiber diameter is failure strength of the fiber is the length of the debonded zone is fiber modulus
In ceramic matrix composite material this mechanism is not a failure mechanism, but essential for its fracture toughness,V. Bheemreddy et al. "Modeling of fiber pull-out in continuous fiber reinforced ceramic composites using finite element method and artificial neural networks," Computational Materials Science, Vol. 79, pp.663-676, 2013. which is several factors above that of conventional ceramics.
The figure is an example of how a fracture surface of this material looks like. The strong fibers form bridges over the cracks before they fail at elongations around 0.7%, and thus prevent brittle rupture of the material at 0.05%, especially under thermal shock conditions.W. Krenkel, ed.:Ceramic Matrix Composites, Wiley-VCH, Weinheim, 2008, This allows using this type of ceramics for heat shields applied for the re-entry of space vehicles, for disk brakes and slide bearing components.
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