# What equation is this defined as?

1. Oct 2, 2009

### elephunk

Is this a stress/strain, or elastic modulus equation? or have I got my understanding wrong?
The question asks where does this come from? I've never seen it before maybe someone can expand for me please?

http://i45.photobucket.com/albums/f98/pastilles/equation.jpg [Broken]

Thanks,

Last edited by a moderator: May 4, 2017
2. Oct 2, 2009

### Mapes

Are you referring to $\gamma=\psi_1-\psi_2$? It's not a stress-strain relation because there's no constant of proportionality that would correspond to an elastic modulus.

Gamma is often used to denote shear strain, though.

3. Oct 3, 2009

### elephunk

Thank you,

I haven't run across this before. I will read some more on shear strain in some textbooks.
Once again thank you :)