Fiber pull-out
Encyclopedia
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.
Work for debonding,
where
In ceramic matrix composite
material this mechanism is not a failure mechanism, but essential for its fracture toughness
, which is several factors above that of conventional ceramic
s.
The figure is an example for 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. 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.
Delamination
Delamination is a mode of failure for composite materials. Modes of failure are also known as 'failure mechanisms'. In laminated materials, repeated cyclic stresses, impact, and so on can cause layers to separate, forming a mica-like structure of separate layers, with significant loss of mechanical...
, intralaminar matrix cracking, longitudinal matrix splitting, fiber/matrix debonding, and fiber fracture. The cause of fiber pull-out and delamination
Delamination
Delamination is a mode of failure for composite materials. Modes of failure are also known as 'failure mechanisms'. In laminated materials, repeated cyclic stresses, impact, and so on can cause layers to separate, forming a mica-like structure of separate layers, with significant loss of mechanical...
is weak bonding.
Work for debonding,
where
is fiber diameter
is failure strength of the fiber
is the length of the debonded zone
is fiber modulus
In ceramic matrix composite
Ceramic Matrix Composite
Ceramic matrix composites are a subgroup of composite materials as well as a subgroup of technical ceramics. They consist of ceramic fibers embedded in a ceramic matrix, thus forming a ceramic fiber reinforced ceramic material...
material this mechanism is not a failure mechanism, but essential for its fracture toughness
Fracture toughness
In materials science, fracture toughness is a property which describes the ability of a material containing a crack to resist fracture, and is one of the most important properties of any material for virtually all design applications. The fracture toughness of a material is determined from the...
, which is several factors above that of conventional ceramic
Ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...
s.
The figure is an example for 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
Thermal shock
Thermal shock is the name given to cracking as a result of rapid temperature change. Glass and ceramic objects are particularly vulnerable to this form of failure, due to their low toughness, low thermal conductivity, and high thermal expansion coefficients...
conditions. This allows using this type of ceramics for heat shields applied for the re-entry of space vehicles, for disk brakes and slide bearing
Bearing
Bearing may refer to:* Bearing , a term for direction* Bearing , a component that separates moving parts and takes a load* Bearing capacity*Bearings, album by Ronnie Montrose in 2000...
components.