shafting: comparison of torsional strength from tensile strength.

[milencio]

is there a an equation relating the torsional strength from tensile strength?

for ex. torsional strength= .5 x tensile strength.
because im calculating for the diameter require for a shaft that is powered by 10 hp motor with 25 rev/min.

im searching for the properties of some material like AISI1010 but the given on the table is always its tensile or ultimate tensile strength.

and where is the reference of that certain equation or law.

thank you in advance.

 

[arunmrao]

0.5-0.6 UTS is a safe assumption.

Learn the rules,so you know how to break them properly.
Dalai Lama

_____________________________________

 

[desertfox]

Hi milenco

As stated by arunmrao 0.5-0.6 of UTS is a safe figure for the maximum shear stress of the material, however I would suggest you put a safety factor on that figure to determine an allowable shear stress for your shaft.
You don't say but have you any other loads on the shaft to consider like bending, tension in which case you may have to look at fatigue

Here are some sites you might find helpful:-

http://www.freestudy.co.uk/c105/t9.pdf

http://school.mech.uwa.edu.au/~dwright/DANotes/SSS/transmission/transmission.html

desertfox

 

[CoryPad]

As stated previously, 0.5 to 0.6 is conservative. The actual answer is:


T = 2/3 · ? · r³ · ?

where

T = torque
? = 3.141 592 654
r = shaft radius
? = shaft material shear strength (~ 0.6 · ultimate tensile strength)

 

[CoryPad]

Forgot the reference:

Strain 41 (2005) 31-32.