Mechanical Engineering - Strength of Materials - Discussion

Discussion Forum : Strength of Materials - Section 1 (Q.No. 34)
34.
When a bar is cooled to - 5°C, it will develop
no stress
shear stress
tensile stress
compressive stress
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
106 comments Page 6 of 11.

DURGESH KUMAR DUBEY said:   9 years ago
If body fixed at both ends then tensile stress will develop, due to cooling contraction will be developed and compressive stress will occur. But because of a bar fixed at both end their tensile stress will be developed.

See the question is not asking about which stress will apply, it is asking about which will develop.

Thanks

Abreeque said:   9 years ago
In this question, gives us tensile stress induced. Can anyone explain?

S.VISHAL said:   9 years ago
Stress is the resistance offered by a material to resist the deformation caused by the force acting. Over here since it is cooling, compressive stress will be acting on the body and the body opposes by tensile force hence TENSILE force is induce in the body. Hence the answer is correct.

Praveen maurya said:   10 years ago
Here, stress = alpha*E*deltaT.

Since delta T will be positive, stress is positive, so is a tensile stree will be developed. Hope it helped.

Lamiya naseem said:   10 years ago
The answer is correct. Actually, when the bar is held at -5 degrees. Temp than it's material tends to shrink but the molecule will resist this deformation and hence apply a tensile stress (stress in opposite direction of the shrink).

Anup said:   10 years ago
Yes, by compressing the material. The compressive force is induced but tensile stress is developed.

Hamed said:   10 years ago
The bar is fixed in both ends, when cooling bar to -5 the bar will shranking because change in temperatue this will produce a reaction forces in both ends will trying to opposite the action of shrinking so those forces will produce tensile stress in the body. Thank you.

Himanshu sharma said:   10 years ago
How can we relate the stress to the temperature?

Please explain.

Ashok said:   10 years ago
When a body is cooled then it contracts. In the above question, it is asked that what stress will be developed when a body is cooled, but not induced stresses, assume that both the ends are connected to a spring when the bar is cooled it contracts to make the spring deform under tensile load.

So tensile stress is correct.

Yogesh said:   10 years ago
@taniya.

The stress never be applied. It developed only.


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