Von mises stress
Von mises stress
(OP)
1. Do we have to look into Von mises stress always even if the material is not yielding ? What other parameters can be seen to justify the level of sress in the component ?
2. There are lot of opinion of limiting the stress value like we have to limit it to 2 element depth ot 3 element depth. Why can't we limit the stress to yield and judge the stress level ?
2. There are lot of opinion of limiting the stress value like we have to limit it to 2 element depth ot 3 element depth. Why can't we limit the stress to yield and judge the stress level ?





RE: Von mises stress
a) multi-directional stress components (sx, sy, shear xy, sz, ...), and
b) failure defined by von mises (you culd also use principal stress, octahedral shear stress, etc).
2) not really sure what you're on about here ... maybe how many elements to put across a stress gradient?
RE: Von mises stress
When we have the results the stress SMX is a numerical value and can be very high, but usually we come up with an absolute value which will be less than the SMX and say that is the maximum stress in the component.
In gist, How do you say what is the maximum stress in the component and I hope it is not SMX ?
RE: Von mises stress
Although in practice it is common for some human interpretation of results from a finite element model, usually this is done in a logical/reasoned fashion. In your case you may have some high stress at a point load or a restraint, for example. In such cases you cannot interpret the results at that position nor can you opt to choose a stress at x elements away from that position as it would be highly unlikely that your point load represents the real situation. Either you will have to represent that part of the model more accurately or totally disregard the stresses at or near that position knowing (in a reasoned way) that in real life such stresses would never exist.
Tata
RE: Von mises stress
how do you come up with "an absolute value less than SMX" ??
RE: Von mises stress
@rb1957... I really did not get you on code ? SMX is in Ansys and am not sure what it is in any other software.
RE: Von mises stress
now, thx to corus' intuition, you've got a high stress peak in your model due to either a load input on a grid or a constraint. if it's a constraint, you can release some of the stiffness by attaching a spring to the model and placing the hard fixed grid off the model. in either case, you've got "some" license in interpreting your model and you should have some logic for this.
i've had cases where the detail modelling was bad (= coarse) so the local results were bad (= high) and we were directed by the job owner to use the stresses in an element 2 bays away ... but i never liked it ...
RE: Von mises stress
Tata
RE: Von mises stress
RE: Von mises stress
I have few more in line.... Will post soon.