doubt about initial conditions

[meccanicamg]

the two straps can be considered united, only from the tree at the bottom moved by the motor,
but the effect of their operation is totally independent and you do not know that
produced by belt 1.
because you were only evaluating belt 2, with effects on the pins of the pulleys, I consider valid the considerations and calculations made with my previous attachment.

If so were the drafts of the cranes with more strings would not have the same shot for each rope.

 

[biz]

hunter, it is not so, we have to treat the mechanism as a carrucole system where there is
only one belt, one fixed hook that is the lower left pin, a force down to the right made by a motor, more different load losses, due to friction, rolling of the load and possibly to the divergence that can have the belt on the two sides of ascent from the load.
I attach a schematic design with numerical example.

Marco, that's the reasoning I used to do. I was in doubt, now, after the reasonings made by @cacciatorino e @meccanicamg I'm even more. compositions for calligraphy and pattern, well treated.

 

[F_Ingrasciotta]

I hope to make a small contribution, I think there's a little confusion because I don't know if it's a static or dynamic analysis.

if you consider only static loads I would say that reasoning @cacciatorino e @meccanicamg I'm back.

If you also consider dynamic loads I would be more aligned to the concept of @marco ferraroni that in the comment #7 spoke of speed and forces (then power) related to the activation of the motor, however I do not agree with the speech that pulleys at the bottom left is not important, if so were the one at the top right would be affected by only vertical forces that will tend to become horizontal as the load is lifted, the use instead of a carruquo in the lower sx makes the reaction on the carrucola only in the high s

so to answer the post for me the ways are 2:

- short but not necessarily decisive --> set 2 analyses with loads and dynamics at the lowest point and at the highest point of lifting (points where I have the maximum alerts due to the start and stop of the engine), then identify the point of greatest stress (so to intuition I would say at the start of the engine, then low load).


- correctly --> set an analysis by identifying a parameter equal to lifting height and identifying the highest load point ( consider static and dynamic loads)


ps: in the first line I would say to consider everything without rolling friction etc... successively implement the main frictions, if by making an analytical estimate it is necessary

 

[biz]

We are not talking about offenses, but only an invitation to give centered answers, because otherwise it only increases the noise and you get away from the goal you would like to reach by intervening on the forum. here are the two straps:
View attachment 68414

Actually, it's 4 straps. There's only two of them here. consider that f is already the force divided on the single belt.

 

[cacciatorino]

It is quite obvious that the differences are about what you mean by load and what you mean by belt.

I have reasoned that:

1. The load is the weight of the whole pipe beam
2. The straps that support the beam are two and take half weight each.

others have already divided the load by two and consider each belt as if made in two pieces. and other variations on the genus. This is unfortunately the problem when cases are set in words instead of explicit graphic patterns.

 

[meccanicamg]

It is quite obvious that the differences are about what you mean by load and what you mean by belt.

I have reasoned that:

1. The load is the weight of the whole pipe beam
2. The straps that support the beam are two and take half weight each.

others have already divided the load by two and consider each belt as if made in two pieces. and other variations on the genus. This is unfortunately the problem when cases are set in words instead of explicit graphic patterns.

I hope we are all able to do split two once or twice... for the rest does not change what we said above.

 

[biz]

I hope we are all able to do split two once or twice... for the rest does not change what we said above.

I don't understand, so let's all say the same thing? beyond the divided two, three,n.
Perhaps in words and without pattern we understand little.
as I initially assumed.

 

[Stan9411]

hunter, it is not so, we have to treat the mechanism as a carrucole system where there is
only one belt, one fixed hook that is the lower left pin, a force down to the right made by a motor, more different load losses, due to friction, rolling of the load and possibly to the divergence that can have the belt on the two sides of ascent from the load.
I attach a schematic design with numerical example.

I think this could end the discussion.
better than this scheme cannot be explained

 

[cacciatorino]

I think this could end the discussion.
better than this scheme cannot be explained

I mean, I'm a project that doesn't explain to me what p is and how many times I have to divide it, I wouldn't take it for good. the initial hypotheses are very vague and consequently the answers cannot be but assumptions. but I under a suspended load whose rope was calculated "taking" something, without any idea that something is real, I would not pass.

 

[Stan9411]

how many times do you have to divide it?
and above all there is nothing to hire, nothing to worry if you walk below. .

the request is simple: Since p, which acts on the band as from schematization of rotten, the distribution of loads on the supports what is it? That's a rotten post. End. if then p is half the weight of the pipes because on the other side there is another belt, we do not know. tant is that:

Actually, it's 4 straps. There's only two of them here. consider that f is already the force divided on the single belt.

I think you're getting too hot on this passage.

Yes, but you have two straps, which have to support each half of the weight of the beam. from which each branch of each belt takes half the middle, i.e. 1/4.

because biz posted the cad and you also see a second strap behind.
If he had posted you a 2d scheme like that of marco, we weren't here to trade.

the question was simple: “as I schematize forces” .. the extent of these forces is influential in answering the question.

 

[biz]

I mean, I'm a project that doesn't explain to me what p is and how many times I have to divide it, I wouldn't take it for good. the initial hypotheses are very vague and consequently the answers cannot be but assumptions. but I under a suspended load whose rope was calculated "taking" something, without any idea that something is real, I would not pass.

Yes, we say that I did not express myself exhaustively in post #1, thinking that it was not necessary to explain for thread and sign the application. even the box that I posted is not understandable probably, however @marco ferraroni has made my own scheme (very more understandable and legible its).
in the end I understand that even @meccanicamg e @cacciatorino They come to the same conclusion.