Steel behavior (strain) under hydrostatic pressure past yield

[ddlmodes]

Below is my question:
A steel of 200Mpa yield, when loaded to:

Case #1)
Stress1=stress2=stress3=400Mpa

Strain1=strain2=strain3
= 0.1% -0.3*0.1% -0.3*0.1% (Elastic strain)
+ A% -0.5*A% -0.5*A% (Plastic strain = no flow = 0)
= 0.04%

Or 0.08%? (After yield, continue to deform elastically)

Under uniform compression, steel should not yield/fail when loaded past yield value.
But the resulting strain is a bit confusing (I post Case #1 first).
Any idea? Thanks in advance.

 

[desertfox]

Hi ddlmodes
Try this link right at the end about Hydrostatic pressure:-

 

[desertfox]

first link didn't work but try this one, if all the principles stresses are equal in compression then there is no yield and the Mohr circle is just a point.

 

[ddlmodes]

Hi desertfox,

Thanks for the lecture link.
I do understand about the point in Mohr circle & non-yielding (for uniform compression).
What I am having doubt is on the strain response.

Will the cube compressed elastically & infinitely as per calculation ie 0.08%
or will it be retarded at 0.04% (strain at yield in this case,
or maybe even later after strain hardening at UTS strain)?