equivalent voltage of von bets

[gaz89]

Hello everyone!! !

a question about equivalent tensions.
then in an exercise with an attached image, once I calculate the various forces and moments agents on the tree I am asked to:
"calculate the equivalent tension of von mises at the most stressed point of the tree"
now the most solicited point is in b.
to calculate eq voltage for vm should use formula
?

but the problem is that I don't have the diameter of the tree in the data, how do I find it? Is it okay with the "maximum cut"?

Thank you very much and I apologize for the confusion

 

[Fulvio Romano]

therefore. . .
1. the formula is wrong. Tau is square.
1b. if it is true point 6, the formula is also incomplete
2. I imagine that t1=t2 and t3=t4, otherwise the system is in transit. confirm?
3. Are you sure the most stressed section is in b? h and k how to schematize them? support? Incastrious? incastri con ceedimento?
4. What is the hypothesis of the maximum cut? on that tree there is twist, bending and cutting. to the eye the cut would seem negligible, but to make two accounts never fail. Why don't you put the equivalent scheme of de saint venant?

I know, I know, you asked for more. I confirm that without knowing the diameter of the tree you do nothing. if the problem does not give you it is because it is probably not an exercise of verification, but of sizing.

 

[meccanicamg]

controls the formula and analyzes cinematism well. If you don't have geometric values, it's because you need to size. However it is a good exercise.

 

[gaz89]

then the full exercise track is attached, but it is not a sizing exercise. . . in the other attachment the cutting diagrams and moment.

the flender moment is max in b so I think it is right to consider b as more stressed section.

max I intended to replace the expressions of sigma and tau tensions in this case (in this case with the hypothesis of von mises) in order to find the diameter, we say with a reverse formula.

 

[gaz89]

*This is the second attachment, sorry

 

[tortellino]

follow construction of machines with prof broggiato?
on the internet you can also find the solution with its steps.

 

[Simo_SRT]

Hello everyone!! !

a question about equivalent tensions.
then in an exercise with an attached image, once I calculate the various forces and moments agents on the tree I am asked to:
"calculate the equivalent tension of von mises at the most stressed point of the tree"
now the most solicited point is in b.
to calculate eq voltage for vm should use formula
?

but the problem is that I don't have the diameter of the tree in the data, how do I find it? Is it okay with the "maximum cut"?

Thank you very much and I apologize for the confusion

attention that the formula of von mises that you mentioned (where tau is square) is only valid for a static tension state or if the fatigued cycles are all of the same type...and on a tree, in the most traditional case, is not so seen that the torque moment is constant and therefore the mt tau are static and instead the flexional and cutting tensions are reversed.

 

[Fulvio Romano]

attention that the formula of von mises that you mentioned (where tau is square) is only valid for a static tension state or if the fatigued cycles are all of the same type...and on a tree, in the most traditional case, is not so seen that the torque moment is constant and therefore the mt tau are static and instead the flexional and cutting tensions are reversed.

Huh?
Maybe there's some confusion. the equivalent sigma of von mises always applies, regardless of the static nature of the problem.
Perhaps you meant that in cases like that of a rotating tree, this approach is wrong? But not the formula, do you think?

 

[gaz89]

follow construction of machines with prof broggiato?
on the internet you can also find the solution with its steps.

hi, no with prof. amodio, could you link me the site with the dispenses of this prof?
Thank you very much

 

[gaz89]

problem solved, I asked prof. today and they were wrong in the transcription of the data not providing the diameter

 

[meccanicamg]

made is that:von bets it is used for ductile materials with realistic valuesgues tresca it is used for ductile and is protectivePower supply it is used for the fragileSimply it is used for pressure vessels with periodic oscillationgough pollard it is used to torsion and flexional synchronous and in phase

In a full circular tree there is the composition of the forces and relative tension states attached, so there is not only a stress.