What is the different between the max stress and the von mise stress

Lorens

What is the different between the max stress in a structure and the von mise max stress in the same structure?

Kindly Lorens

arildno

I'm not quite sure if I'm answering your question as you want, but:

1. From my hazy recollection, the von Mieses "(max) stress" in a structure is the YIELD criterion of the structure; i.e, if the local stress exceeds that value, plastic flow will occur.

2. Max stress in a structure is simply that: the maximal stress value in the structure.

Clearly, the max stress in the structure must be below the von Mieses yield criterion to ensure that plastic flow does not occur.

Lorens

But in Fem you often look in to the von miese stress, and you can list the von mises stress for the diffrent nodes ...

arildno

Hmm..but that would surely mean the material has non-uniform properties (and, hence, different yield criteria)?
It is in principle unproblematic of making a non-constant yield stress function. In that case, the requirement is that the local stress does not exceed the local yield criterion.

I'll see if I get someone else to look in on the thread..

EDIT:
As kindly provided by another member, perhaps your problems are resolved by taking a look at:
http://www.engineersedge.com/strength_of_materials.htm

buscae

Hi All
I m new here, I have few basic queries, if anyone can clarify on same.
Que1):-For any linear static FEA analysis,w hy do we consider mostly Voin Misses stresses?Why not Principal or any other stresses ?
Que2):-Does Epsilon Values depends on elasticity or Density?