Effective Strain Calculation for MEng Materials

[darkelf]

Hi,

I need some help here. I'm an MEng Materials with no full background in engineering. So I'm in a bit over my head.

I'm trying to understand the concept of hydrostatic stresses and effective strain in connection to worn surfaces. I am told I just need to know the equations but then I'm a bit confused.

I'm trying understand how equivalent strain is calculated from the shear angle of the interface θ.

In other words how this equation came about


E (Z) = (square root of 3/3) * tan theta


Can anyone please guide/help me?

Thanks.

 

[Senay!]

Stress is the ratio of applied force to the perpendicular area and strain is the ratio of. Change in length divided to the original length! What about the strain of a steel?