Tensile Stress Catalog Values

[beton1986]

Hi;
I'm searching for material Tensile Stress. In material catalog,Is the tensile stress of material engineering values or true values?

 

[rb1957]

i imagine you mean tensile yield stress or tensile ultimate stress ... these are "material engineering values", interpreting "true values" to mean the actual vlaues of youe pieces of material

 

[beton1986]

I understand it. I have got yield and tensile strength values of material. ? lern it in catalog. Is this engineering? OK?

 

[rb1957]

?

the term "material engineering values" means (to me) values determined by materials engineers (using the principles of materials engineering).

if you've got a value from a catalogue, it depends on the reliablity of the catalogue.

 

[trainguy]

beton1986,

Is your question related to true strain vs engineering strain as interpreted by your software package?

If so, you should check your software manual to see which it requires.

If you are asking about if typical materials info is based on engineering strain or true strain, the following may help:

http://en.wikipedia.org/wiki/Deformation_(mechanics)

tg

 

[ishvaaag]

But normally, yes, catalog list "engineering porperties", i.e., based on the undeformed shape of the tested part. In other words, and only as an example, the limit stress given multiplied by the original (lesser) section of the test bar would give the limit load.

 

[ESPcomposites]

Generally speaking, the reported results from a material (test data) is reported based on the original section (engineering stress). They don't try to update the area during the test since that would be impractical.

For FEM, you may consider the true stress, based on an updated area (if it really is significant). The FEM can only see the updated geometry so it needs a true stress.



Brian

http://www.espcomposites.com

 

[kan123]

By the way, the FEM will only see the updated geometry if you have selected some sort of large displacement option. Most codes default to linear solutions with small displacement assumptions so that reported stresses will be with respect to the original geometry.