calculation frame with beams arranged to x

[gerod]

I wanted the eq to be written. depending on an angle!
But the pantographs are like this!

 

[Fulvio Romano]

I didn't put the pen on the sheet, but I gave a quick look at the calculations. It seems obvious to me a gross mistake, so gross that I'm probably wrong.

if you have a hinged connection at the ends, it is a tie or a dot. the forces to the hinges therefore can only be aligned to the connection.

in fact lacks normal effort on the base and on the basket, which are an integral part of the structure.

If my wife doesn't see me, I try to throw down some accounts, too.

 

[Gianp80]

x gerod : you are right is the same discussion and I apologize, but I am so desperate that I ran the risk of being resumed by the moderators....the equations according to an angle imposed upon you once I checked a load configuration, otherwise I'm going to do a doublely tiring job.... and if you help me solve all the drawings and correct calculation reports.....

Is there no bending in the beams? If so, how do you transmit strength between the various elements???? I can't understand... .

about the structure of the cinematics they work because they were redesigned watching a live machine, therefore based on experience. . .

 

[Fulvio Romano]

Is there no bending in the beams? If so, how do you transmit strength between the various elements???? I can't understand... .

the force is transmitted as a balance of the structure. Imagine a triangle with the hinges in the vertices. you can upload it as you want (but only on the hinges), the triangle will remain rigid without any of the links being pressed down.

in your case this is not entirely true, because the piston presses at the center of a beam, then on that the bending is there.

I'm a little rusty with the accounts, but I was trying the following way:
We know that in central hinges there can be no force, and this for symmetry issues.
we can also, always by symmetry, cut the structure (was the method of rettering) on the two orthogonal symmetry planes. at this point it is possible to study only a quarter of the structure, assuming to add on the cuts the forces exercised by the remaining part. (this is true only by neglecting the weight of the elements, but we end up)

therefore obtain only three elements with hinges at the ends.

a static problem is always linear, you can then use the principle of overlaying effects. a first effect is that of the load of the basket ra4. a second effect is that of the internal tensions of the beams.
now, you have a structure (a quarter structure) that is labile. the force of the piston crosses the whole structure and goes to compensate ra4. the structure does not collapse thanks to its symmetries, so the forces on the cutting sections will have to balance the remaining connections.

I feel that the forces on the central hinges (which in the whole structure are scarce) must be horizontal.

therefore. We know the angle of the cylinder, and at the next step you should parameterize everything according to this angle. break down its horizontal and vertical force. the vertical component will be equal to ra4, the horizontal one must be verified to the cardinal equations of the static together with the two forces (horizontal) on the cutting sections and on an additional horizontal force to the basket. this represents the normal effort of the basket that must necessarily collaborate to the structure.

to all this it is then possible to add the weight of the objects as an additional effect. this of course only after having "reassembled" the structure, because now symmetry is no longer valid.

You should be there.

Let us know

 

[gerod]

not having done 4 accounts by hand I did not dare to say that they lacked horizontal forces; is correct what says lightning: horizontal forces may not be null. when you study balances remember that the sum of forces is nothing... maybe you have equal and opposite horizontal forces.

x giamp: be careful because you've already been warned once! However, in the world of work it is also necessary not to wait for the help of others but to find solutions sometimes resetting.

follow the advice of lightning: parameterize!

 

[Gianp80]

gerod I apologize again: (but I hope for this you will want to forgive my insolence.. .

Your suggestions about them calmly tomorrow dear Roman Cardinal... they seem quite exhausting and detailed. . .just imposed again the calculation with the new public method all

x gerod: in the work I think that a 40,00mm diameter round and a 60x120mm boxed beam 5mm thickness is ultra sufficient to withstand the loads in play , considering using a 120mm hydraulic actuator with 220bar pressure


Thank you very much to all of you

 

[lucacort]

Forgive the intromission. . .
in the written report in doc format of calculations I do not understand
because the q load applied on the basket also includes the weight of the beams below.

 

[Gianp80]

x lucacort: q load is estimated in that way only to oversize bearing beams

x all participants in the discussion I am solving the structure with the method of ritter, with the method of balance of the knots, and with the study of the free body diagrams of the various structural elements taking into consideration also the horizontal forces on the various hinges. Let's see that it comes out and then I'll show you everything

 

[Fulvio Romano]

x lucacort: q load is estimated in that way only to oversize bearing beams

I have not followed the reasoning of lucacort, but if it is true, oversize the beams in this way has the same structural logic that multiply the area of the section for the earth-light distance divided lazy for the earthly circumference. . .

 

[Gianp80]

then the fundamental point is: to solve the static of the structure... .

all the rest (parameterization of the loads on the joints according to the lift corners, analysis of the loads agents on the structure, position of the q load of the project, checks to the tipping, effect of the wind) for me are only details... if I can not solve the static in a relatively simple load configuration to study, what sense does a detailed analysis of the loads and a parameterization of the equations?

Therefore, you want to consider the model developed for calculation as a preliminary model surely to correct and refine

 

[Fulvio Romano]

then the fundamental point is: to solve the static of the structure... .

fully agreed. Go on like this.

one of the most frequent errors I observe in my working life is to run behind the myriad of details, often mistaken in full the main road.

your approach is the correct one, regardless of the quality of the results.

There is who to build a house starts by choosing the wallpapers, you are dimensionalizing the foundations.

 

[Ing.Vedder]

Interesting question!
I hope I have time to take a look. .

e.v.

 

[Gianp80]

I hope so too

if someone has solved numerically it is prayed to publish so you can compare the results obtained...thanks. . .