Hey guys.(adsbygoogle = window.adsbygoogle || []).push({});

It's been a long time since I've done anything beyond a simple shear stress calculation, so have what will hopefully be a basic question.

I've found similar examples but not ones I was confident I could apply to mine.

As per the dodgey paint sketch I've made below, I have this scenario where I have a hollow cyclinder a-c (door shaft)which is driven by Fd which is acting on distance Lad.

Lets assume that all horizontal arms a-d, b-e, and c-f are rigid, so basically I really only need to look at Ta Tb and Tc

The hollow cylinder is supported by a thrust bearing at 'a' in all directions, x,y,z, and by a roller at 'c' which supports x and y.

Lets ignore the weight of this single welded frame.

Now points 'e' and 'f' can either hit a fixed object at the same time, or independently.

1) In the case that only 'e' or 'f' hit a fixed object, that solution is statically determinate, and Fd = Fe, or Fd = Ff.

Correct?

2) In the case that 'e' and 'f' are both limited by a fixed object, such as a wall, I need to determine the distribution of forces, or the Torque, at points 'b' and 'c'. I believe I need to work with the polar moment of inertia to solve this?

Thanks a million in advance,

Macca

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Statically indeterminate tube in Torsion

**Physics Forums | Science Articles, Homework Help, Discussion**