material parameters for fem

[stef_design]

Hello, everyone. In the meantime I thank those who have responded to the previous discussion (normal strength).
I have another question to ask you.
fem program libraries are not always complete. I therefore wanted to create other materials, following the parameters of the existing ones.
I don't understand why compressive ultimate strength is 0 while the tensile ultimate strength (I assume it is the yield limit) has a value.
While in 2 images, for cast iron I have a precise value.
Thank you.

 

[stef_design]

while in the 2 image, for cast iron I have a precise value.
Thank you.

I'll answer in part. cast iron is a fragile material and therefore only the traction and compression breaking data are inserted and not the snerv limit.

cmq do not understand (see picture 1) as never the ultimate strength tablet is 0 while the yield strength tablet has a precise value.

 

[stef_design]

Excuse me, but I reply to this discussion myself:

generally in steels the compression yield voltage of the material is equal to that of traction (sigma sc = sigma st = sigma s).
when carrying the compression yielding material you have a similar decrease in tension yielding tension (bauschinger effect).
the figure below shows this effect and the typical shape of the stress-def curve that is obtained by deforming a material beyond the yield limit cyclically.

therefore in my case the value of tensile/compressive yield strength (elastic traction/compres limit) is equal while for compressive ultimate strength is equal to 0 because the breakage occurs only in traction.

 

[stef_design]

I ask you a kindness, what value would you insert as a breaking load (traction) for the plastic indicated?

Find material data at the top:
44 mpa is the limit si snelvamento... but the one to break

 

[stef_design]

I ask you a kindness, what value would you insert as a breaking load (traction) for the plastic indicated?

Find material data at the top:
44 mpa is the limit si snelvamento... but the one to break

Hi.
someone can help me:redface:
What rupture limit would you put?
Thank you.