Material Stiffness Comparison

This is an attempt to show comparative material characteristics by illustrating their stiffness while also considering overall weight.

Deflection at the unsupported end: the formula is: Wl3/3EI

Where:

In this illustration the low cost carbon loaded beam deflects under load 1.5 times as much as steel. It is better in some ways than steel. For example, the tensile value is up to 5 times as great, it is 1/5 the weight for the same size and can be 1/20 the weight for the products that have repeated loadings such as connecting rods, automobile drive shafts and springs. Notice the high strength carbon fiber exceeds steel while keeping all of the weight and tensile advantages.

Carbon fiber classifications: (Ref: Steel has a modulus of 30,000,000 psi)

• UHM (ultra high modulus). Modulus of elasticity > 450GPa (65,000,000 PSI)
• HM (high modulus). Modulus of elasticity range 350-450GPa (50,000,000 to 65,000,000 PSI)
• IM (intermediate modulus). Modulus of elasticity range 200-350GPa (30,000,000 to50,000,000 psi