Which statement correctly describes the typical advantage of CFRP over GFRP?

Which statement correctly describes the typical advantage of CFRP over GFRP?

• A. Lower cost per stiffness unit
• B. Same stiffness-to-weight ratio
• C. Higher stiffness and strength per unit weight, but higher cost
• D. Lower density

Answer: (C)

The key idea is that carbon fiber offers much higher stiffness and strength per unit mass than glass fiber, and CFRP leverages both the stronger fibers and a lower density. This means you get more rigidity and load-carrying capability for the same weight, or you can achieve the same stiffness with less weight by using CFRP. The trade-off is cost: carbon fibers are more expensive than glass fibers, so CFRP parts tend to cost more. While lower density helps reduce weight, the practical advantage that designers seek is the combination of higher stiffness and strength per unit weight, even if that comes with higher material cost.

The key idea is that carbon fiber offers much higher stiffness and strength per unit mass than glass fiber, and CFRP leverages both the stronger fibers and a lower density. This means you get more rigidity and load-carrying capability for the same weight, or you can achieve the same stiffness with less weight by using CFRP. The trade-off is cost: carbon fibers are more expensive than glass fibers, so CFRP parts tend to cost more. While lower density helps reduce weight, the practical advantage that designers seek is the combination of higher stiffness and strength per unit weight, even if that comes with higher material cost.