Composite Materials MCQ with answer and solution

Concept

Kevlar-29 is an aramid fibre with high tensile strength, about 2.8 to 2.9 GPa.

Step-by-step solution

1. Kevlar is an aramid fibre used in FRP composites. 2. Kevlar-29 has a tensile strength of about 2800 to 2900 MPa. 3. Kevlar-49 is the higher modulus grade, with a similar or slightly higher strength. 4. The nearest option is 2860 MPa.

Explanation

Kevlar-29 is a common aramid fibre used in FRP. Its tensile strength is about 2.86 GPa, which is close to 2860 MPa. So option A is correct.

Why the other options are wrong

B, C, D: 3860, 4860 and 5860 MPa are too high for Kevlar-29. Those values are in the range of high-strength carbon fibres.

Shortcut

Kevlar-29 has a strength of about 2.9 GPa. Pick the value near 2900 MPa.

Common mistake

Mixing up Kevlar-29 with Kevlar-49 or with carbon fibre strength values.