Fibre-reinforced plastic (FRP) (also called fiber-reinforced polymer, or fiber-reinforced plastic
is a composite material made of a polymer matrix reinforced withfibers .
The fibres are usually glass (in fiberglass),carbon (in carbon fiber reinforced polymer),aramid, or basalt.
Rarely, other fibres such as paper, wood, or asbestos have been used.
FRP allows the alignment of the glass fibres of thermoplastics to suit specific design programs.
Specifying the orientation of reinforcing fibres can increase the strength and resistance to deformation of the polymer.
Glass reinforced polymers are strongest and most resistive to deforming forces when the polymers fibres are parallel to the force being
exerted, and are weakest when the fibres are perpendicular.
Thus, this ability is at once both an advantage or a limitation depending on the context of use.
Weak spots of perpendicular fibres can be used for natural hinges and connections,
but can also lead to material failure when production processes fail to properly orient the fibres parallel to expected forces.
When forces are exerted perpendicular to the orientation of fibres, the strength and elasticity of the polymer is less than the matrix alone.
In cast resin components made of glass reinforced polymers such as UP and EP, the orientation of fibres can be oriented in two-dimensional
and three-dimensional weaves.
This means that when forces are possibly perpendicular to one orientation, they are parallel to another orientation;
this eliminates the potential for weak spots in the polymer.