# Torque transmit by shaft

1. May 26, 2014

### vsp_6887

I have a two shaft 1) hollow shaft 2) solid shaft . both has same length.

Condition 1) If diameter of both this shaft is same, which shaft can transmit a more torque? how?

condition 2) If cross section area of both this shaft are same then which shaft can transmit more torque? how?

Please reply with calculation & theory & example if possible...

2. May 26, 2014

### Mech_Engineer

I think it's pretty obvious this is homework so I'll have to do my due diligence: what do you think? Have you done any work? What lectures have you had in class which discussed this?

3. May 26, 2014

### vsp_6887

Actually this is a question ask during my 1st interview..

I read earlier this & reply for condition i think 1 ) ans is solid shaft & for condition 2) Hollow shaft

But i do not find clear answer why ? what is the reason...

4. May 26, 2014

### Mech_Engineer

So I guess the interview didn't go well? Have you taken a class in this topic?

The strength of a shaft in torsion is controlled by its material properties, and the cross-sectional torsion constant a.k.a. the second moment of area. You may try calculating the shaft strength for each case using some made up numbers to see what you come up with, I think it could help with your understanding...

http://en.m.wikipedia.org/wiki/Torsion_(mechanics)