Question

A co-joined cross-ply laminate composite, as shown in the figure, is distorted upon heating. What are the resultant shapes of edges XY and YZ? 

• A. \( X \longrightarrow Y, Y \longrightarrow Z \)
• B. \( X \longleftarrow Y, Y \longrightarrow Z \)
• C. \( X \longrightarrow Y, Y \longleftarrow Z \)
• D. \( X \longrightarrow Y, Y \longrightarrow Z \)

Hint:

When dealing with composite materials subjected to heat, consider the differing coefficients of thermal expansion of each layer and their effects on the overall shape of the structure.

Answer 1

The Correct Option is C

In the case of a co-joined cross-ply laminate composite, where the laminate consists of alternating layers of different materials (e.g., ceramic fibers and polymer matrices), the composite distorts upon heating. This is because the different materials expand at different rates due to their distinct thermal properties, leading to distortion.

Step 1: Understand the composite behavior.
When the material heats up, due to the mismatch in the coefficients of thermal expansion between the layers, the material tends to warp. The layers oriented in different directions (X and Y) will cause the edges to bend in a particular direction. The edges of the material are distorted as follows:
- The edge \( X \) distorts toward \( Y \) (expanding or compressing).
- The edge \( Y \) distorts in the opposite direction toward \( Z \).

Step 2: Conclusion.
Therefore, the resultant shape of edge XY is \( X \longrightarrow Y \), and the resultant shape of edge YZ is \( Y \longleftarrow Z \).

Final Answer: \text{(C) \( X \longrightarrow Y, Y \longleftarrow Z \)}