Safety factor

Hello

In the room, I get a safety factor between 3 and 10^16. I'm below the elastic limit. I would need help setting the security coeff options.

Step 1: I put von Mises constraint

Step 2: Yield Limit

Step 3: this part that interests me, area below the safety coeff, in my case I leave 1 or I put 3? The material is 316L stainless steel with a yield strength of 190 N/mm².

 


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Unless I'm mistaken, it just manages the display.
In your case, if you have s=3 at the minimum, it means that the maximum stress is 3x190=570N/mm².

Weird, my max stress is 61.5 N/mm² and not 570

Hello

correct me if I'm wrong, but normally

Coef sécu --> 1 > σ Von mises / elastic σ?

And if it can help: 

http://help.solidworks.com/2013/french/solidworks/cworks/r_maximum_von_mises_stress_criterion.htm

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Hello Snouzy13

Hello

You always make the same mistake which is to tell Solidworks here I want a safety coeff of 3 so am I on the right track? even! Put me the right thickness.

Well, I've already told you, that's not  how simulation works. It's not predictive but gives you a design result. This calculates from the existing material.

If you want to make a predictive imitation, you have to go through the topology or even the generative topology.

Let's get back to your case

Let's take an example!

You make a 1 mm sheet metal part, you do a bending simulation.

As a result, the sheet metal deforms too much. Damn!

You change the thickness of the sheet metal and go to 1.5mm

New simulation is better but it still flexed too much so you go to 2 mm

Phew, it's good in Von bets and with a security coefficient of 1.3

No need to go any further because it will be over-quality.

Obviously, old  croutons like me, just looking at the room, know with a very good probability what it will resist. As a result, from the outset, they put the right thickness at 92%. This is less true for complex shapes!

In addition, don't let yourself be blinded by the simulation tool because tell yourself that it will always be the weakest element of your whole that will be out of the norm or that will break.

In your case, this will be the bone or the hole you make in the bone. In addition, you have an error which is your fixed  point (partition or other). Also, as we have seen, putting the two rods parallel is not the best solution. (cf. the other discussion).

In summary, simulation allows you to move from a probabilistic system (the experienced person who knows more or less the resistance) to a deterministic system.
The deterministic system, which is the PEF  calculation, calculates the resistance node by node according to multiple parameters, gives you the result that is closest to reality. Because the reliability of the result depends on the form but above all on the way SW simulation is used, as we have seen during our various exchanges.

I see too many erroneous simulations and therefore with consequences on the real world for me not to take the time to make you put your finger on what is wrong.

I hope you will understand the very principle of reality, simulation is not Voodoo, although it can be hallucinogenic by making you believe that your conception is correct or wrong when it is the opposite in both cases.

Kind regards

 

 

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