{{Short description|One of the failure mechanisms in fiber-reinforced composite materials}} {{Use American English|date=March 2021}} {{Use mdy dates|date=March 2021}}
'''Fiber pull-out''' is one of the failure mechanisms in fiber-reinforced composite materials.<ref name=cantwell>{{cite journal | author=WJ Cantwell, J Morton | title=The impact resistance of composite materials -- a review | journal=Composites | year=1991 | volume=22 | issue=5 | pages=347–62 | doi=10.1016/0010-4361(91)90549-V}}</ref> Other forms of failure include delamination, intralaminar matrix cracking, longitudinal matrix splitting, fiber/matrix debonding, and fiber fracture.<ref name=cantwell/> The cause of fiber pull-out and delamination is weak bonding.<ref>Serope Kalpakjian, Steven R Schmid. "Manufacturing Engineering and Technology". 6th Ed. Prentice Hall, Inc. 2009, p. 223. {{ISBN|0136081681}}</ref>
Work for debonding, <math>W_d = \frac{\pi\; d^2\; \sigma_f^2\; l_d}{24\; E_f}</math> <ref>PWR Beaumont. "[https://doi.org/10.1016/b978-0-08-024766-3.50012-4 Fracture mechanisms in fibrous composites]". Fracture Mechanics, Current Status, Future Prospects. Edited by RA Smith. Pergamon Press: 1979. p211-33 in {{cite journal | author=WJ Cantwell, J Morton | title=The impact resistance of composite materials -- a review | journal=Composites | year=1991 | volume=22 | issue=5 | pages=347–62 | doi=10.1016/0010-4361(91)90549-V}}</ref>
where *<math>d</math> is fiber diameter *<math>\sigma_f^2</math> is failure strength of the fiber *<math>l_d</math> is the length of the debonded zone *<math>E_f</math> is fiber modulus
thumbIn ceramic matrix composite material this mechanism is not a failure mechanism, but essential for its fracture toughness,<ref>V. Bheemreddy et al. "[http://www.sciencedirect.com/science/article/pii/S0927025613004278 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.</ref> 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.<ref>W. Krenkel, ed.:''Ceramic Matrix Composites'', Wiley-VCH, Weinheim, 2008, {{doi|10.1002/9783527622412}} {{ISBN|978-3-527-31361-7}}</ref>{{pn|date=January 2024}} 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.
== References == {{Reflist}}
Category:Composite materials