problem

[ford]

determine the diameter of a tree subject to bending moment of 850nm and which must transmit a power of 20kw at a speed of 150 rpm. use the mohr criterion by assuming a material with st=200mpa and sc=500mpa and assuming a safety factor of 3.

Thank you very much to all those who will help me.

 

[Preparation-H]

determine the diameter of a tree subject to bending moment of 850nm and which must transmit a power of 20kw at a speed of 150 rpm. use the mohr criterion by assuming a material with st=200mpa and sc=500mpa and assuming a safety factor of 3.

Thank you very much to all those who will help me.

confused:

I'm missing something like that, but do we have to fix it? :bekle:

 

[MBT]

determine the diameter of a tree subject to moment flettente of 850nm and which must transmit a power of 20kw at a speed of 150 rpm. use the mohr criterion by assuming a material with st=200mpa and sc=500mpa and assuming a safety factor of 3.

Thank you very much to all those who will help me.

What's the point?
There must be a mistake!
or do you consider a straight simple bending, constant throughout the axis?? ?

 

[cacciatorino]

What's the point?
There must be a mistake!
or do you consider a straight simple bending, constant throughout the axis?? ?

Perhaps they mean the moment of flenching due to the pull of the belt chain of the gear tooth or whatever it is.

 

[MBT]

would not be constant, but variable with the distance from the supports.
therefore, either has a scheme of the tree or is not resolved.
or asks to analyze only that section, considering twist and bending... but then miss the cut (and not that of black... )
to me it seems a case "academic" of tree subjected to constant bending and torsion.

 

[cacciatorino]

would not be constant, but variable with the distance from the supports.
therefore, either has a scheme of the tree or is not resolved.
or asks to analyze only that section, considering twist and bending... but then miss the cut (and not that of black... )

I know the second you said, unless it is the section of the section between the two supports of a tree with the external bouncing pulleys: in this case the mf would be constant throughout the inner part.

 

[MBT]

Anyway, I don't get to work at it.
because I do not see such complexity as having to ask for help

 

[ford]

This is a text of the past years, I posted it as they gave it to me, I didn't write it directly... ah now rereading I missed to write minimum bending moment of 850 nm.
so there may also be some error in the text.

 

[ford]

then, I calculated the torque moment from the formula of power and I have 1274 nm. I calculated the diameter from the equation: mt=n*wt and I have 60 mm. Finally I calculated the tangential voltage max doing mt/wt and I have a tao of 30 mpa. building the graph of the criterion of mohr, the circle relative to the tao falls into the area bounded by the envelope therefore should not yield.
Now I wonder (as long as it's right):
- what was the point of providing the moment data?
- possible that the resolution of an examination text is so short?
enlighten me.

 

[davide75]

Maybe it depends on the "new order" university......

cmq is not even required to calculate bearings? Is it hard to check? the verification of any tabs? ?

 

[cacciatorino]

30 mpa.

And your dice....

- what was the point of providing the moment data?

you have to calculate the voltage due to the bending moment, and then find the equivalent voltage generated by normal voltage (due to bending) and tangential voltage (due to to torsion).

Sure that if these are the examination texts of the new order we are well placed.... these are questions from fourth year itis, as says mbt....

 

[davide75]

Just....as I said earlier...if there was something in which we could say that we were "strong" was the university.... then with the new order. . .
I apologize for the oct but my examinations of constructions of machines in which blood was spitting, but in the end the matter really dismissed it in everything and for everything.

 

[ford]

Maybe it depends on the "new order" university......

cmq is not even required to calculate bearings? Is it hard to check? the verification of any tabs? ?

This is part of another examination which is constructive elements of the machines.

 

[ford]

it is said tau....



you have to calculate the voltage due to the bending moment, and then find the equivalent voltage generated by normal voltage (due to bending) and tangential voltage (due to to torsion).

Sure that if these are the examination texts of the new order we are well placed.... these are questions from fourth year itis, as says mbt....

cmq I am doing the three-year, there will be other examinations always in this area, there is constructive elements of the machines, science of the constructions, constructions of machine to the specialist etc.
However I agree with you that with the new order the preparation of the engineers is less than what you had with the old order, but this is and we have to keep it. thanks cmq of the straights.