Mechanical Engineering - Strength of Materials - Discussion

The right answer is compressive stress.

And when free bar then hired then no thermal stress dovlepod.

When a bar is cooled to - 5° C, it will develop.

Actually, this question denoted 'a bar '.

It is not Mentioned as the bar is fixed, hinged, both sides fixed it. So the bar is free, not fixed and hinged.

That's why the answer is ' no stress '.

(If it is mentioned as "one side is fixed" then the answer is compressive stress generate).

Thank you.

Correct answer is tensile stress.

Here -5 degrees denotes that there will be an initial temperature
Thermal stress= E alpha ΔT,
ΔT= T2-T1.

If T2 is -10 degrees that means ΔT =-10-(-5)=-5 degree which means compressive,
If T2 =10 degree.

ΔT= 10-(-5)=15 which means tensile stress . So the answer will be tensile.

If the temperature of the bar is lowered, then the nature of stress & strain will be?

If the bar is cooled, it will shrink. But the internal forces will resist that by producing force in opposite direction to shrinkage which means the internal forces produce tension. So the answer is tensile stress if the bar is fixed.

But here the bar is not under any restraints. So there will be no stress.