lifting blocks aluminum 10tonn

[Er Presidente]

so much to make horrified the friends of the forum.
I don't know if you have the possibility to weld, but the plate could be connected with 4 screws to the block to be lifted. if they work 2 at a time (in the worst conditions) they have to endure at most 4.3 t.
excuse the quality of the design but I had at the moment nothing but a pen and the paper of the focaccina ...:biggrin:View attachment 14983

Guodo, guodon!

aluminum is traitor, must work with distributed load and distributed a lot.
weld a beautiful wide plate with such beautiful welding, so the aluminum does not notice the effort and you make it split!

 

[PaoloColombani]

Thank you... very explicit ... but you would really do me a favor... the concept is clear to me... I try to make some calculations too.

Hi.

then, since there is this balance between the intake section and the section of the screw core (always that lives and mothers are of the same material) in order to verify the seal of a mothervite of different material you can assume to have a screw (in your case m42) built with this same type of material (in case, 5083) and verify the tensile strength of the section of the core of this hypothetical screw:

Now, the 5083 should have 125 mpa to yield.
I remember that: [1 MPa = 1·10e6 N / m² = 1 N / mm²]with perpendicular traction on the top of the section this material will reach the yield when approximately 125 n on each mm2 will be applied

a m42 metric screw big step should have a hazelnut of 37.5 mm in diameter. you get the section exposed to stress:

= 3.14 · 18.752 ≈ 1100 mm2

the load with which you reach the yielding of the hazelnut:

qmax = σs · sn = 125 · 1100 ≈ 137 000 n

the value is lower than I had given you earlier because quickly I had calculated on the nominal diameter and not on the diameter of the hazelnut.
this is also the stress that can safely carry the mother of this material for a grip height of 0.8 · dn, or 34 mm.


the critical tension that acts of cutting on the threaded surface can be obtained by reverse.

τ = qmax / s

where sf is the cylindrical section that represents the thread:

♪
with h = 0.5 · dn (critical tension, not in safety)

with a few steps you will choke:

τ 2.2≈ σs[MPa]which can be useful in fast calculations on the sections to be filed.

These criteria are coarse as a colleague points out, especially when connecting very different materials, however they represent a fairly indicative and fast method in case you intend to verify and stay much below critical values.

Hi.

 

[PaoloColombani]

Indeed, in the speech made by doves, we should also consider the elastic form of materials and their fragility.
when a screw is in grip on a mothervite the first thread of the mothervite is the most stressed and then the solicitation as you pass to the next thread decreases until you cancel after a number of threads.
in case I have two materials with the same elastic module but with different yield resistance, the first thread, the most loaded, rinse and plasticize and transfer the load to the next threads.
if the material besides being little robust is also fragile (with little plasticization) there is the danger that the first thread breaks before passing the load to the next ones, and therefore the speech of having more threads in socket is no longer valid.

hello wave,
Yes, I have supprased these considerations because I thought we should make a very gross verification, being very far away from critical tensions and certain elongation values.
in fact with even more particular materials those criteria could not be applied, not even in a gross way; I imagine, for example, a steel screw on a glass screw, or quartz. probably there would be no more proportionality, the stresses would not be able to distribute, and the critical trension the threads could jump in sequence as in a domino.

reasoning absurdly, threading a screw into the plastic that has an elastic module about 70 times lower than that of steel, each plastic thread takes the same load as the steel screw does not deform.

thinks that when I was writing to motiplicate the threads in the grip I made this trip, I imagined a threaded steel bar screwed into a huge cube of polypropylene.


Hi.

 

[Exatem]

Guodo, guodon!

aluminum is traitor, must work with distributed load and distributed a lot.
weld a beautiful wide plate with such beautiful welding, so the aluminum does not notice the effort and you make it split!

I didn't have time to make calculations (but I do it in the morning!). but welding a plate of the same material, perhaps with some welding rods, and dimensionalizing the gulf.. .
but how do you think the gulfs are put on the decks of the alloy ships?
p.s: in the previous post I was not clear. I meant that if it is not possible to weld the plate, you could connect the same with "n" screws on the block.

 

[tvi71it]

a m42 metric screw big step should have a hazelnut of 37.5 mm in diameter. you get the section exposed to stress:

= 3.14 · 18.752 ≈ 1100 mm2

the load with which you reach the yielding of the hazelnut:

qmax = σs · sn = 125 · 1100 ≈ 137 000 n

Thank you so much... I agree... more or less I arrived around those values too.

In the end, I also heard the very positive opinion of the customer, I think we will opt for the solution I had described at the beginning of the discussion ...

thanks, however, to all for the various opinions and suggestions, which have been a stimulus to the discussion

greetings
tvi71

 

[Fulvio Romano]

Guodo, guodon!

aluminum is traitor, must work with distributed load and distributed a lot.
weld a beautiful wide plate with such beautiful welding, so the aluminum does not notice the effort and you make it split!

Yes, the idea is good, except for the fact that welding aluminum is not really trivial. apart from costs, it is likely that welding is little more than a bonding with pritt.

but how do you think the gulfs are put on the decks of the alloy ships?

Yes, but do not underestimate the fact that ships are soldered by naval welders... in my modest opinion there is no welder in any industrial area able to arrive at the expertise of a naval welder. that is people who speak with the metal flow as it descends into the china and convinces the material, using a special dialect, to enter into deep intimacy with the parts to join.

 

[Exatem]

Yes, the idea is good, except for the fact that welding aluminum is not really trivial. apart from costs, it is likely that welding is little more than a bonding with pritt.

Yes, but do not underestimate the fact that ships are soldered by naval welders... in my modest opinion there is no welder in any industrial area able to arrive at the expertise of a naval welder. that is people who speak with the metal flow as it descends into the china and convinces the material, using a special dialect, to enter into deep intimacy with the parts to join.

Don't believe yourself, once it was like you say. I've seen welds on the construction site, to be shredded. by now the labor is "globalized" so it can happen (in large yards) that the welder is a poor extracommunist who has never seen before a welding. They give him some electrode, a pliers, and they say, "Do it soon."
Then the good thing is that the control officer notes the cauliflowers, maybe pictures them and inserts them in his beautiful relation, but now it's done and it's okay.
today I couldn't make two small businesses (I was on board all day). If I can try tomorrow afternoon.
Say hi.

 

[Er Presidente]

... (I was on board all day). ...save.

aboard?!? !
on the submarine?!? ! ? !

p.s.: I recommend, do not open the oblo'!! ! !
:biggrin:

 

[sampom]

(I was on board all day).

exa reripeto:
"but that's cool."

..and I wait for new:wink:

greetings
Marco:smile:

 

[Exatem]

aboard?!? !
on the submarine?!? ! ? !

p.s.: I recommend, do not open the oblo'!! ! !

No, vulgar surface ship.
p.s. those who open the portholes on the smg, are of another weapon :biggrin:
Bye-bye

exa reripeto:
That's cool. !

..and I wait for new

greetings
Mar

Yeah, that's why... :finger:
I have to send you an e-mail as soon as possible.
Hello Marco