Mechanical Engineering - Strength of Materials - Discussion

Because the member with lesser coefficient of linear expansion will try to stop it from shrinking and it applies tensile stress to it.

@Gaurav : the Explanation is not Correct.

It is simply because, the member of Greater Coefficient of Linear Expansion will tend to expand (Extended), as if it is subjected to tensile Stress, there is relation with any member with lesser coefficient of linear of expansion, plus there is no shrinking happening in any member wether it is having low or great coefficient of linear expansion.

For development of any stress it's whether tensile or compression in thermal stress.

Cross section must be prevented to change.

Actually for rise in temperature, Linear of coefficient expansion is low it will expand;as here there is a fall in temp. So, the coefficient of linear expansion is high it will have compress.

Correct me, If I am wrong.

Consider Cu & Steel as a composite member. (a) Cu > (a) steel. For rise in Temp, Cu want to expand because it have higher coe. Of linear expansion but Steel will contract & Steel will try to resist Cu to expand thus Cu gets compressive stress on it. It is exactly opposite when there is fall in Temp.

It Means Cu will have tensile stress & Steel have Comp. Stress when there is fall in Temp.

When there is a fall in temperature, member having greater coefficient of linear expansion will contract more than the other one which will thus apply a tensile stress on the first one.

Hence, If there is a fall in the temperature of a composite body, then a member having greater coefficient of linear expansion will be subjected to tensile stress. (B).