Shaft Rupture torque

[Alesek]

How to calculate Shaft Rupture torque?
I do have material properties and shaft dimensions.
The rupture torque will be related to the weakest point of the shaft.

 

[redpicker]

It depends on what you mean by "rupture".
If you mean exceeding the yield strength, then you can define it as when the stress exceeds the yield strength.

S=Mc/I

S=Stress
M=Torque moment
c=radial distance
I=4th momemnt of inertia

Changes in diameter will create stress concentrations, which you may need to determine, and cross sections more complicated than a simple circle will make calculating the moment of inertia more complicated.

rp

 

[rb1957]

i think I should be J =Ip =Ix+Iy =2Ix for a round bar
M = T, c = r

same question though ... what is failure ? exceeding yield ? (simple elastic stress dist'n) or fully plastic ?? (not so simple non-linear stress dist'n) ...

more details would stop us guessing

 

[Alesek]

I mean by rupture when the shaft will brake.

 

[redpicker]

i think I should be J =Ip =Ix+Iy =2Ix for a round bar

You are probably correct. I was just going from memory, which hasn't been used for this equation for decades.

rp

 

[CoryPad]

Get NASA RP 1123 Design of power-transmitting shifts , a free document that shows calculation methods:

http://ntrs.nasa.gov/search.jsp?R=7...=false&qs=Ns=HarvestDate%7c1&N=4294888910+282

 

[rb1957]

"shifts" = "shafts" ... and yes, i know the error's from the NASA site