CFRP (Isotropic)

The material. Carbon fiber reinforced composites (CFRPs) offer greater stiffness and strength than any other type, but they are considerably more expensive than GFRP (see record). Continuous fibers in a polyester or epoxy matrix give the highest performance. The fibers carry the mechanical loads, whereas the matrix material transmits loads to the fibers and provides duc­tility and toughness as well as protecting the fibers from damage caused by handling or the environment. It is the matrix material that limits the ser­vice temperature and processing conditions.

Composition

Epoxy + continuous HS carbon fiber reinforcement (0, н— 45, 90), quasi­isotropic layup.

General properties

Density

1500 –

1600

kg/m3

Price

*40.0 –

44.0

USD/kg

Mechanical properties

Young’s modulus

69 –

150

GPa

Yield strength (elastic limit)

550 –

1050

MPa

Tensile strength

550 –

1050

MPa

Elongation

*0.32 –

0.35

%

Hardness—Vickers

*10.8 –

21.5

HV

Fatigue strength at 107 cycles

*150 –

300

MPa

Fracture toughness

*6.12 –

20

MPa. m1/2

Thermal properties

Maximum service temperature

*140 –

220

°C

Thermal conductor or insulator? Thermal conductivity

Poor insulator *1.28 –

2.6

W/m. K

Specific heat capacity

*902 –

1037

J/kg. K

Thermal expansion coefficient

*1 –

4

p, strain/°C

Electrical properties

Electrical conductor or insulator? Electrical resistivity

Poor conductor *1.65 X 105 –

9.46 X 105

pnhm. cm

A CFRP bike frame. (Courtesy TREK.)

Typical uses. Lightweight structural members in aerospace, ground trans­port, and sports equipment such as bikes, golf clubs, oars, boats, and rac­quets; springs; pressure vessels.