type di studio?

[Wolverine]

Hello, everyone!
I installed solidworks, I have to do a fatigue test, the problem is that where
you have to define the type of study there is only static, while I have seen on the guide that you can make also the choice of fatigue, but it does not appear between the options, how to do?

Thank you!

 

[re_solidworks]

you need to install a solidworks simulation license. simulation included in premium solidworks only treats static.

 

[Matteo]

a fatigue sizing also you do it with a simple static analysis knowing the properties of the material and calculating sigma of vonmises and main sigma

 

[Fulvio Romano]

a fatigue sizing also you do it with a simple static analysis knowing the properties of the material and calculating sigma of vonmises and main sigma

infinitely agreed.
I have never found myself with fatigue analysis of the fems, especially in the compaction of loads (for example rainflow) in case of cyclic missions

 

[Wolverine]

Thanks for the answers!
Hello! !

 

[Wolverine]

a fatigue sizing also you do it with a simple static analysis knowing the properties of the material and calculating sigma of vonmises and main sigma

Could you please tell me, in general, how should I proceed, note this information?

Thank you!

 

[Matteo]

Could you please tell me, in general, how should I proceed, note this information?

Thank you!

in extreme synthesis: a good parameter (without claiming to be the only) for the estimate of the risk of fatigue breaking is the main maximum effort, compared with the characterization of the material and the state of overall effort. difficult to express everything in a few lines, but find many useful things here:

Introductionhttp://it.wikipedia.org/wiki/tensione_internahttp://it.wikipedia.org/wiki/continuo_di_cauchyhttp://it.wikipedia.org/wiki/cerchio_di_mohrfatiguehttp://it.wikipedia.org/wiki/cedimento_a_fatica_dei_metallihttp://it.wikipedia. org/wiki/diagramma_di_w%c3%b6hlerhttp://it.wikipedia.org/wiki/cedimento_a_fatica_dei_metallihttp://www.gruppofrattura.it/ps: except in very rare cases where a "brutal" solution is attempted, tending to the "microscopic", the approach of calculation software to the problem of fatigue follows the probable considerations of wohler and the miner considerations on the fracture.

 

[Fulvio Romano]

in extreme synthesis: a good parameter (without claiming to be the only) for the estimate of the risk of fatigue breaking is the main maximum effort, compared with the characterization of the material and the state of overall effort. difficult to express everything in a few lines, but find many useful things here:

mmmhh. .
Why the analysis of the main? Is it not enough for you, von mises, without bothering Mohr? I believe that the situation is easier to manipulate mentally if one trusts von mises and one thinks that it is the only sigma to take into account... so in the end a steel, in the vast majority of cases, always yields to the maximum, do you think?

With regard to fatigue...it is not an account to be done after studying a bit on wikipedia, it is true that the degree in engineering is only "a piece of paper", but now we do not exaggerate.
Trying it by fem, after reading wikipedia is even more dangerous. . .

Could you please tell me, in general, how should I proceed, note this information?

In principle, a good approach should start with the following considerations:

- how hard does it affect the machine?
- Does the material admit a fatigue limit?
- Are tensions likely to result in a oligocyclic fracture?
- programmed inspections can avoid a non oligocyclical fracture?
- what statistical margin I have, considering the wohler curve
- can there be training or counter-works?

all this, possibly, before taking the calculator into hand and start shooting figures at the "dog engineer".

 

[cacciatorino]

I don't know anything about fatigue analysis with finite elements, but it seems to have seen that there is a type of modeling, which in code-aster calls x-fem, which simulates the propagation of the cracks in the body under load. Perhaps the author of the discussion referred to this type of modeling.

 

[Wolverine]

First of all I thank you all for the answers!
That's my problem.
We imagine, for example, that we have a certain mechanical piece of steel, subject to a certain load, we imagine with cycle from scratch.
then the approach I thought is as follows.
I evaluate the tension of von mises at the most stressed point.
I evaluate the amplitude of thetasigma=sigma von mises - 0, seen that the tension is nothing at the moment when the piece is unloaded and comparison then this delta with the admissible delta of project.
I would like to know whether or not this is the criterion, so if the deltaxigmas have to evaluate them on the basis of the tensions of von mises, or should we evaluate them with other criteria?

Thank you! !

 

[Matteo]

mmmhh. .
Why the analysis of the main? Is it not enough for you, von mises, without bothering Mohr? I believe that the situation is easier to manipulate mentally if one trusts von mises and one thinks that it is the only sigma to take into account... so in the end a steel, in the vast majority of cases, always yields to the maximum, do you think?

the max prin sigma (with reference to a complex object analyzed by fem) to distinguish compression states from traction states (very much more dangerous in the perspective of the propagation of the clique).

ps: What does this thread have to do with swx?