Question

A composite bar consisting of two different materials having same length and same cross- sectional area will have the same

• A. Stress
• B. Strain
• C. Load sharing
• D. Poisson's ratio

Hint:

For composite structures, remember the key compatibility condition for each arrangement:
- Parallel bars (loaded axially): Strain is the same.
- Series bars (loaded axially): Stress (and Load) is the same.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question concerns a composite bar made of two different materials joined together and asks which physical quantity remains identical in both materials when subjected to an axial load.

Step 2: Key Formula or Approach:
For perfectly bonded composite members of equal length, compatibility of deformation requires both materials to undergo the same extension. Since strain is extension divided by original length, the strain in both materials must be equal.

Step 3: Detailed Explanation:
Because the two materials are rigidly connected, they cannot elongate independently. Their increase in length is identical, and since the initial lengths are also the same, the strain remains equal in both members. However, the stresses are generally different because each material has a different modulus of elasticity. Consequently, the load carried by each member also differs, while Poisson's ratio depends on the material itself and is therefore not the same.

Step 4: Final Answer:
In the composite bar, the quantity that remains the same for both materials is the strain.