transferable moment

[AngeloB]

Hello everyone
I attach the calculation process of a flanged joint called for torsion.
max. transferable moment for friction is about 61 knmt
to you the bill?
keep in mind that I have held a 0.2 steel-aluminum friction cof which is perhaps pessimistic, could go even 0.5.
If I prescribe a torque of 980 nmt can I trust to transmit at least 61 knmt?

thanks for the help

 

[gerod]

cutting screws are not always a great idea even if the work is at the expense of friction.
a couple of thorns would be ideal.
the calculation seems correct even if I would be on the side of the cheese: If the screws transmit 61 nm, I expect the transmitted torque to be lower so as to have a safety coeff.
Hi.

 

[AngeloB]

with this calculation the screws do not work to cut.
However the prisoners, even if you do not see, have a cylindrical trait that works, in part, as a plug.
the joint should work with max. 40-45 knmt. apart from a particular condition, rare motion, at 72 knmt
According to you, considering that the material is at least 725 mpa, can I prescribe the 980 nmt clamping?
Hi.

 

[Fulvio Romano]

cutting screws are not always a great idea even if the work is at the expense of friction.
a couple of thorns would be ideal.
the calculation seems correct even if I would be on the side of the cheese: If the screws transmit 61 nm, I expect the transmitted torque to be lower so as to have a safety coeff.
Hi.

with this calculation the screws do not work to cut.
However the prisoners, even if you do not see, have a cylindrical trait that works, in part, as a plug.
the joint should work with max. 40-45 knmt. apart from a particular condition, rare motion, at 72 knmt
According to you, considering that the material is at least 725 mpa, can I prescribe the 980 nmt clamping?
Hi.

the screws can work to cut, if at the point where the cut the screw is not threaded.

I didn't see all the data well, but how about putting a safety coefficient on the friction?
if the piece before being mounted, falls and is collected by the worker with the dirty hands of oil, does it work the same?
if who from the couple has a point that can for a few moments overcome the friction of first posting what happens?

 

[AngeloB]

When I check sleds with sliding shoes I consider a coef of friction equal to 0.1. If I consider 0.2 I think of caution, however the test of the friction coef is easy to do, as soon as there is a little time I go to the workshop to do it.
however a joint of the genus fine even cutting, the prisoners (not seen in the drawing) have a cylindrical trait working in a steel bushing planted in the light alloy
the coupling is not accurate as if it were 16 thorns but if the flange began to twist surely the stem of the prisoners would begin to cut, as soon as a stem bends the subsequent stems begin to work and distribute the load.

 

[gtemp]

Hi.
excuse ignorance but I have questions to ask about the calculation executed:

1 safety coeff has been fixed but then in subsequent formulas it is never considered
2 in the tasmissible force do not understand the value below fraction of 1.5

Thank you.

 

[gtemp]

Hi.
excuse ignorance but I have questions to ask about the calculation executed:

1 safety coeff has been fixed but then in subsequent formulas it is never considered
2 in the tasmissible force do not understand the value below fraction of 1.5

Thank you.

Hi.
excuse ignorance but I have questions to ask about the calculation executed:

1 safety coeff has been fixed but then in subsequent formulas it is never considered
2 in the tasmissible force do not understand the value below fraction of 1.5

 

[gerod]

And what is it?
Do you requote?
You know it's forbidden to make up! !

 

[gtemp]

Sorry gerod, I didn't know, I was looking for a way to get someone's attention to answer my questions.

 

[giampiero.volante]

kind angel b

I performed the calculation according to manual formula of the engineer and with the
Transmissible torque according to your data we are (generally according to me it is always better to use however the diameter of hazelnut for the resistant section of the screw).

As for the tightening couple, I wasn't very convinced
the coeff 0.2 you used in formulas I then performed the procedure reported on a text of construction of machines (forgive me but I do not know if the rules of the forum allow to attach partial reproductions of texts) that takes into account
of friction between nut and flange (1.5*db) and friction between screw threads and mother-in-law with alpha (helical angle) pe (helical pass) f' (coefficient thread friction) and roof (throw angle) and result is approximately 20%.

If my calculations are + accurate it would mean that in your case you don't seem enough screws and therefore the traction force you generate is lower.

if it is possible to attach the full treatment please inform me that I do.

Thank you and welcome

balloon

 

[gtemp]

Good morning.
still remaining my questions about the calculation performed by angelb,
I add for giampiero.volante where is the formula that you used on the engineer's manual? What machine construction text did you use?
Thank you.

 

[giampiero.volante]

Good morning! Sorry for the forgetfulness:

manual of the mechanical engineer hoepli
chapter on discs (page 1126)

lessons on machine organs
Filipino davoli gorla lo conte (clup)
3.4 flange connections of pressure vessels
3.4.3 clamping

I hope I've been fully enough

greetings giampero

 

[gtemp]

Thank you.
excuse the insistence, help me understand the value 1.5 in the calculation of the transmissible force for friction in the calculation performed by angelb.
Thanks again

 

[AngeloB]

I have rejected my procedure, I hope I have been clearer.
I promise I'll study what was written by a tripper.
because we do not try to make ourselves a manual to calculate these things, we do a section on purpose, we agree how to expose the various problems and then we solve them and deepen them all together.
What do you think Gerod?
greetings

 

[gerod]

for me you can do (I answer to the request of a section).
It's to understand how to do it.
or we create a new discussion open to all or I don't know and I wouldn't want to create sections for only a few.
Tell me about you.
Hi.

 

[AngeloB]

we could open it to all but establish how to expose problems
for example
- all files in *.dwg format
- Avoid the 3d
-explain the problem
-explain how the solution is tempted
- always add a numerical example
- separate femcals

 

[gtemp]

I have rejected my procedure, I hope I have been clearer.
I promise I'll study what was written by a tripper.
because we do not try to make ourselves a manual to calculate these things, we do a section on purpose, we agree how to expose the various problems and then we solve them and deepen them all together.
What do you think Gerod?
greetings

thanks for the completeness of the solution.
I want to add that value 1.5 should be a safety coefficient,
on the niemann (manual of the organs of the machines) is defined as a minimum safety coefficient of sliding.
If you want I can send you a pdf of the page in an mp.
Hi.

 

[gtemp]

we could open it to all but establish how to expose problems
for example
- all files in *.dwg format
- Avoid the 3d
-explain the problem
-explain how the solution is tempted
- always add a numerical example
- separate femcals

could be useful to professional growth.

 

[mariom]

Angelob's idea is very interesting, I hope he followed.

 

[Pastorman75]

mark it, as did another, that for the calculation of the screw throw you must consider the "hazel diameter" of the same.
It seems to me that for the use of the approximate formula it should be remembered that the vine-rosetta surface should not be oiled/greased.

greetings