Composite Materials MCQ with answer and solution

Concept

Polyethylenes (HDPE, LDPE) are tough, flexible plastics that resist repeated loading (fatigue) well.

Step-by-step solution

1. Fatigue resistance means the material can take repeated loading without cracking. 2. Polyethylenes (HDPE and LDPE) are tough and flexible, so they resist fatigue well. 3. PVC/CPVC are more rigid and brittle under cyclic loads. 4. SIP is a sandwich panel, not a plastic material. 5. So the answer is HDPE & LDPE.

Explanation

HDPE and LDPE are tough and flexible plastics. They can bend again and again without cracking, so their fatigue resistance is excellent. This is why they are used for pipes, tanks and films.

Why the other options are wrong

A: PVC and CPVC are rigid and less good under repeated loading. C: SIP (structural insulated panel) is a panel product, not a plastic. D: ABS is known for impact strength, not mainly for fatigue resistance.

Shortcut

Tough and flexible plastic means good fatigue resistance, so choose polyethylene.

Common mistake

Confusing impact strength (ABS) with fatigue resistance.