loaded support

[mir]

as in the attached drawings I have a loaded support (are several media that hold a cover). clearly each support carries a load part and in my case is 4200 n. with algor (von mises) I get a stress of 302.99 n/mm^2 on the curve, just where I expected to have the critical condition. seen the rp[0.2]=180 n/mm^2 (inox aisi304) this is not good, however, I am a little puzzled about the correctness of the analysis, i.e. it seems excessive the stress calculated by algor.

Some willing, with another fem maybe, could you see what results you get?

attached find the .sat file

thanks to the help and availability
♪

 

[gerod]

Why is the cargo trapeze?

you could also make a verification but first verify that the results are acceptable (convergence crisis, mesh, etc.)
If you stick the mesh you might find even higher tensions.

Before you say that algor chanted, do a hand-collar (it is simple abstention).
At least you have an order of magnitude.

Finally, it may be that the maximum voltage is reduced to only one point (single points). fem results must be interpreted.
Hi.

 

[SOLID]

However, I am a little puzzled about the correctness of the analysis, i.e. the stress calculated by algor seems excessive.

If you look well you have a very small connection, so that value is plausible.
In any case the area you reported seems to me quite limited and more subject to compression.
Usually some designers, when analyzing the structures, observe only the main maximum sigma, to intervene only in the areas subject to traction.

 

[mir]

I attach an account made perhaps too quickly and on an empty stomach because I find myself an irresponsible figure.

 

[mir]

If you look well you have a very small connection, so that value is plausible.
In any case the area you reported seems to me quite limited and more subject to compression.
Usually some designers, when analyzing the structures, observe only the main maximum sigma, to intervene only in the areas subject to traction.

that area is subject to cutting and bending and compression... or is it not?

 

[mir]

why is the cargo trapeze?

he wanted to mean that the load is vertical... and i came to draw it with that absurd form.

 

[Onda]

Are you sure you didn't put an extra zero in the cargo?
It seems to me that your vertical faces are loaded from a constant moment and that their sigma is about 212 mpa against 21 mpa that should result from your manual account.
now that the fem gives a high value in the connection radius can stay. But that gives 10 times so much on the flat faces no. here it seems to me that in the fitting gives you a value about 1.5 times that present on the flat faces that is congruent. try to review the input data of the fem.

 

[mir]

I checked, I put 4200 n of load.

I'm a rookie with the fems, but maybe the mistake lies in the loading. I did so (it seems like a standarized procedure also in other fems):

- mesh (in the sense of creating mesh and not pouring )
- selection of the meshata surface where to apply the load
- surface force stick of - 4200 n (the least is to indicate the load down)

Now I would not want the surface force to be wrong as distributed load of 4200 n :s

 

[mir]

Are you sure you didn't put an extra zero in the cargo?
It seems to me that your vertical faces are loaded from a constant moment and that their sigma is about 212 mpa against 21 mpa that should result from your manual account.

I should like to see if I have done the right hand

 

[Onda]

I think you're wrong.
I remade them and brings 176mpa for bending.
I also added the cut, although I find it conservative this procedure since the maximum cut is located in the center and the maximum bending on the outside.
in any case doesn't change much.

 

[mir]

I ran into my formidable ti-89 titanium and put a quarter of an hour to see that I forgot to make the sigma square!

I confirm your result to 177,745 mpa which is slightly below the 180 mpa of the snake[0.2].


for safety step to a thickness of 12 mm I think it gives me a sigma of 123.84 mpa.

 

[Onda]

I still think the result of the fem was correct.
in the fold you have a concentration of tension, it follows that you easily have 1.5 times the nominal voltage of the flat faces.
you should remodel with elements + small and see how the tension rises.
of course on the greater thickness.

Hi.

 

[mir]

with a thickness of 12 mm load to 220 mpa (always at the same point clearly).

Now I wonder if it is not better to stay at 10 mm thick and insert a reinforcement triangle under the fold.

what do you recommend?

Has anyone made the fem with some other program that I am curious to see other results?


greetings
♪

 

[Onda]

satisfied!
solidworks fem.
the value I find is slightly higher than yours because I made a thicker mesh (I imagine).
in any case I suggest you increase the fold radius and see what happens.

Hi.
wave

 

[mir]

Thank you.

 

[SOLID]

that area is subject to cutting and bending and compression... or is it not?

Of course, but the von misess take into account both the traction components (flasse) and the cutting components.

However, having done a linear static analysis, all values above the yield are always overestimated, as you are not considering the plasticization curve of the material.

 

[mir]

ok I understand, so I can say I manually verify the 12mm thick support (at 10 I approached too much to the rp limit[0,2]=180 mpa) even if according to the fem there is a critical condition that reaches up to 220 mpa. However, I cannot understand whether this is a correct reasoning of the use of fem.