Torsional shear

darkmagic

1. The problem statement, all variables and given/known data

Given:
hollow steel shaft
Torque = 5400 Nm
Torsional Shear = 150 MPa

Required:
Inside diameter
Outside Diameter
Stress on the inside of the shaft

2. Relevant equations

3. The attempt at a solution
I solved both the diameters which are 64.49 mm and 48.37 mm.
I dont know what formula to use to determine the stress on the inside of the shaft

I used to 16T/[pi d^3) where d is the inside diameter. Am I correct?

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rock.freak667

Homework Helper
In general

T/J = (shear stress)/r

so shear stress = Tr/J

at the outer, r = outer radius

at the inner r = inner radius

darkmagic

The J and r are already substituted in the formula I used. Ok thanks.

darkmagic

Is J there the J of the smaller circle, with the inside diameter? I got 243 Mpa which is larger than 150 Mpa.

rock.freak667

Homework Helper
Is J there the J of the smaller circle, with the inside diameter? I got 243 Mpa which is larger than 150 Mpa.
Your shaft is a hollow one, so the J = (π/32)(douter4-dinner4)

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