EE Noodling in a box of blocks 3

[aghaderi]

Hi Guys,
So I have this project that it’s a bit complicated to explain. Imagine that you have a square like in Figure1. There are some small parts that will be moving in this square only. These parts have to be interconnected and they have to build up and move to the top as shown in Figure 2. So there is a test that it has to be done on these small blocks and if one of them falls out there should be another block that has to move automatically and then fills in the gap as shown in Figure3 (Generally fill in the block that’s missing). I really don’t know anything about mechanical engineering so please don’t judge me. I’m an Electrical Engineer so please if you have any idea how I could design this thing that would be a life saver. Again any help will be deeply appreciated.

Thank You.

 

[zeusfaber]

You're right about it being hard to explain!

First: A reminder that we don't do Students' homework for them here. It's not clear whether that's what you're asking for yet, though I strongly suspect it might be

Some things we don't understand yet:

Are you 1. trying to create a mechanical model that illustrates the abstract rules you've started to define, or is this 2. a real system that you have to define a new function onto.

If 1, you will need to define the rules in more detail before you can start to model them

If 2, you will need to provide more detail about how the existing stuff is implemented, and where the bit you are trying to add on starts.

Interconnected how? How does one part influence another? If you actually meant "overlapping" rather than "interconnected", then what is the order of overlap when you consider rows as well as columns?

Are "blocks" the same thing as "small parts" - or are they collections of "small parts"?

Moving in this square only? In going from Fig 1 to Fig 2 you seem to win some parts. Have the new parts come from outside the square? How is that allowed? Then you talk about a block "falling out"?

Sir Ernest Gowers (In "The Complete Plain Words") suggested that if a writer cannot describe something clearly, this is often because they do not themselves understand the point they are trying to make. You can take that either as a criticism or as a powerful tool: Why not go back over your description and flesh out all the bits that are painfully vague - sorting out the missing detail in your own mind as you go. You may end up understanding the problem well enough to tackle it yourself.

A.

 

[aghaderi]

Hi Zeusfaber:

Thanks for you reply. Sorry for the mis-confusion . So to answer the the first question, this is not a home work problem and this is a real life application. I work in a medical device company that requires to build a wall that has small parts that should be overlapping on each other from the bottom and they will be building on each other as they move to the top. I am dealing with a very high radiation area and the reason that the block will fall out is because there is a safty test to insure that the patients will not be exposed to any radiation meanwhile they are recording the study. This is the only design that we can really implement and there is no other way. Hospitals will not allow any other modification to there windows. The answer to the question that you had regarding the change from figure 1 to 2, there will be the same small parts behind each small parts in figure 1, so a collection of small parts (due to the fact that this is a 1D graph its hiding beneath the other small parts). As the wall moves up the other small parts will move to the top (figure 1 to 2). At the end the safety test will be done on the wall as shown in Figure3 to insure that there will be an external block to replace the effected block if the wall fails to function normally. Im not a Mechanical Engineer but ill be more than happy to provide any details of this project to clarify things a bit.

Best,
A.G

 

[prex]

You didn't raise any question. What's your question?
And what the hell are those small parts, how do they overlap, how do they build up, how should they move replacing one missing part, what dimensions, materials, shapes, and so on , and so on.
We really don't understand anything of what you are saying.

prex
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[zeusfaber]

Still lots of gaps and things that don't add up here. Strange bits of design that might be there for reasons that will influence all sorts of other decisions:

What is the purpose of the wall? Is it a radiation shield?

Do you just need to build the wall once and leave it there forever, or does the process need to be reversible?

How big is the window you are trying to cover. Has somebody told you how big the small parts (I think I'm going to call them "scales") need to be?

Building a wall from the bottom is unusual. Is this because the place the wall is going will be irradiated while the wall is being built, and the building needs to take place out of the beam? If so, this has major implications for the "replace a scale in-situ" bit of the story, which looks like its going to happen in a bad place.

Why lots of little interlocking scales? Is this because the wall has to be flexible? If so, you can't really expect it to be self-supporting (you've used words like "bottom" and "top", so I'm assuming this is vertical). Many scales means many gaps which, in the context of radiation shielding, means many opportunities for failure. It isn't the scales that fail.....

"not allow any other modification...". So there's some existing infrastructure that needs to be interfaced with, and maybe an existing design you can copy? If there are guide rails and lifting wires, it would be good to know about them. You will certainly need to know how much space is available for your building operation and what arrangements there are for feeding materials in as you go.

What drives the requirement to replace a bad scale in the middle of the wall? Can you test scales before they are fed into the assembly? Can you test the joints between adjacent scales before they have slid beyond the build-zone. If you do those things, can you get yourself sure enough that the final safety test is going to pass that it becomes economic to assume that you will just destroy the wall and start afresh if the final test fails - especially if the build process needs to be reversible in the first place?

Are you sure there is no prospect of installing a shutter or curtain stored on a roller into the space that would otherwise be occupied by your builder machine - or to build your wall from slats rather than from scales (perhaps using two layers, with the front layer covering the joins in the back layer), maybe hooked onto a suspension cable at either end?

It still feels like you understand the proposed solution more than you understand the problem.

A.

 

[gerhardl]

Hello aghaderi!

I fully understand the necessary action of not giving any detailed equipment description away. But, regrettably, only general advice can be given based on such sketchy information.

Valuable information would be size, transportation and filling method and devices, fluid or firm, electro-mechanical or fluid or air transportation etc.

Generally you are asking for redundancy: a safety doubling up of filling, or a complete doubling with an extra system, getting in operation 'immediately' if system no. 1 fails.

1. Which time limit do you have before backing up is necessary?

2. What type of physical reaction can you use to detect failure?

3. Based on answer to Q.2: What type of signal detection can you use? Note: Transmission of backup release impulse can be transformed to 'anything'- wide choice here.

4. Possibility of 2 or 3 parallell systems, with changing to another and shutdown of one?

5. Possibility of 'extra feeding/filling of existing system?

6. Other solutions: emergency system shutdown if failure? (Repair, refilling and start again)

7. As 6, but screening in front released in stead of shutdown ?

If this shall be solved with mechanical operation at all, solutions will be depending on your answers for point 1. and 2.

Hoping this try for analyze of the problem will help!

 

[aghaderi]

Hi Prex:
See your answers in red below,
You didn't raise any question. What's your question?
How could I design such thing.
And what the hell are those small parts, how do they overlap (they have a small cutout that will allow them to fit into each other), how do they build up (That's exactly the reason that I have posted this online), how should they move replacing one missing part (again I'm a electrical Engineer that is filling the mechanical engineer position due to the fact that he got lay doff), what dimensions (I cant disclose this information), materials (only material that can with stand high radiation), shapes (the shape of these part have to be in ellipse), and so on , and so on.
We really don't understand anything of what you are saying. (I apologize for the inconvenience but I can disclose some information, again im not a mechanical but if you can help me to build a fixture like this with any dimensions, shape and material, this will save my life. thank you.)

 

[aghaderi]

Hi zeusfaber:

thanks for your replays, Please see your answers in red,

Still lots of gaps and things that don't add up here. Strange bits of design that might be there for reasons that will influence all sorts of other decisions:

What is the purpose of the wall? Is it a radiation shield? Yes that is the main reason that the wall is there.

Do you just need to build the wall once and leave it there forever, or does the process need to be reversible? This process has to be reversible.

How big is the window you are trying to cover. Has somebody told you how big the small parts (I think I'm going to call them "scales") need to be? Again I cant disclose this information but just imagine a doors fixture as for the size of the window. As far as the "small parts" the smaller the better, so 6"x4" per each "small Part".

Building a wall from the bottom is unusual. Is this because the place the wall is going will be irradiated while the wall is being built, and the building needs to take place out of the beam? If so, this has major implications for the "replace a scale in-situ" bit of the story, which looks like its going to happen in a bad place. There is a fixture already built but the door has to be open in pieces incase of an emergency, they cant have an solid door.

Why lots of little interlocking scales? Is this because the wall has to be flexible? If so, you can't really expect it to be self-supporting (you've used words like "bottom" and "top", so I'm assuming this is vertical (Please see the answer above and yeah that exactly right, the movement is Vertical). Many scales means many gaps which, in the context of radiation shielding, means many opportunities for failure. It isn't the scales that fail..... (You are a better expert at this then I am, that's absolutely right. There will be gaps that need to get filled, I cant answer the question of "how?")

"not allow any other modification...". So there's some existing infrastructure that needs to be interfaced with, and maybe an existing design you can copy? If there are guide rails and lifting wires, it would be good to know about them (At this moment there is non). You will certainly need to know how much space is available for your building operation and what arrangements there are for feeding materials in as you go. (At this moment we have almost 2 feet from each side of the door fixture to load these "small Parts")

What drives the requirement to replace a bad scale in the middle of the wall? (Safety requirement, FDA failure Test) Can you test scales before they are fed into the assembly? (that would be a great idea) Can you test the joints between adjacent scales before they have slid beyond the build-zone.(sorry I cant understand this one, could you explain this a little more in detail?) If you do those things, can you get yourself sure enough that the final safety test is going to pass that it becomes economic to assume that you will just destroy the wall and start afresh if the final test fails - especially if the build process needs to be reversible in the first place?

Are you sure there is no prospect of installing a shutter or curtain stored on a roller into the space that would otherwise be occupied by your builder machine - or to build your wall from slats rather than from scales (perhaps using two layers, with the front layer covering the joins in the back layer) (that sounds like a genius idea!!!), maybe hooked onto a suspension cable at either end?

It still feels like you understand the proposed solution more than you understand the problem.
That's true, I am an EE rather than a ME. They have set the descriptions that I provided and they just want me to provide them with a solution. Again any help will be appreciated and I will try to answer any questions up to the best of my knowledge. Now If you would have a project like this how would you design it, how would the small parts move, which method would you use?

 

[IRstuff]

How thick are these scales? Can they be made with tongue and groove joints, which would eliminate any direct path through the wall?

TTFN
I can do absolutely anything. I'm an expert!
homework forum: //

http://www.engineering.com/AskForum/aff/32.aspx

faq731-376 forum1529

 

[aghaderi]

Hi gerhardl:
thanks for you reply, please see my comments in red,

I fully understand the necessary action of not giving any detailed equipment description away. But, regrettably, only general advice can be given based on such sketchy information.

Valuable information would be size, transportation and filling method and devices, fluid or firm, electro-mechanical or fluid or air transportation etc.

Generally you are asking for redundancy: a safety doubling up of filling, or a complete doubling with an extra system, getting in operation 'immediately' if system no. 1 fails.

1. Which time limit do you have before backing up is necessary? (could you apply this to a real life scenario?)
if you mean what is the time limit that the action needs to be taken, this will be immediately.
2. What type of physical reaction can you use to detect failure? (Physical electrical contact, this will be done with a 0 or 1 Logic system)

3. Based on answer to Q.2: What type of signal detection can you use? Note: Transmission of backup release impulse can be transformed to 'anything'- wide choice here.

4. Possibility of 2 or 3 parallell systems, with changing to another and shutdown of one? this is a good feature
I just know the original thought, you could design anything that will make sense to you.
5. Possibility of 'extra feeding/filling of existing system? Sorry im not a ME, I really don't know, again its up to you to decide how you
would like to load the small parts
6. Other solutions: emergency system shutdown if failure? (Repair, refilling and start again) (again this is a great feature, designing this
is up to you, what ever you think is the best solution.
7. As 6, but screening in front released in stead of shutdown ? There is an FDA Failure test that has to be done, the fixture has to replace the effected part immediately, shutdown is the next step of stooping the procedure.

If this shall be solved with mechanical operation at all, solutions will be depending on your answers for point 1. and 2.

Hoping this try for analyze of the problem will help!
Thank you for your fast response, I really appreciate your help in this matter. Again I'm not an ME and I'll try my best to answer any question that you have.
Best,
A.G

 

[aghaderi]

Hi IRstuff:

Thanks for your response, please see my comments in red,

How thick are these scales? (Almost 2-4 inches thick) Can they be made with tongue and groove joints, which would eliminate any direct path through the wall? ( That's a possibility, but if I want to do the FDA failure Test, which is pushing a Small part out by force how are we going to place another part in between immediately? )

FYI, I'm not a ME so its up to you how you would like to design this Fixture, you have the ability to work with anything, this is a wall that will stand in front of a high radiation.
Best,
A.G

 

[Jboggs]

aghaderi: I have seen your post here and on another forum. Amid all the confusion you are hearing about, the most important fact that stood out to me is this: you work for a medical device company building equipment for high radiation areas that just laid off the only mechanical design talent they have. Its hard to imagine a situation with more risk of high liability. I have read everything written here and have some advice for you. You are WAY over your head. And if management does not realize that already, it is your job to inform them. They need to get some other help on this project. From what I can tell, you can't even define the process well enough to build a prototype for testing. And that's not a slam on you. Its a statement of fact. I would be in the same position if management expected me to design a control system for a medical device. You really do not want to try to design a medical device for use in a high radiation area based on advice from nameless folks on the internet. To get an idea what that really means, just imagine hearing those words being said from the witness stand of the product liability trial.

 

[zeusfaber]

"...FDA Failure test, which is pushing a small part out by force..". From what you'd said up to now, I had assumed that the test was one of radiation leakage, not structural integrity.

- which begs the question of why somebody feels the need to test whether bits of the wall will withstand a sideways load without breaking off. The only answer I can imagine is that somebody has foreseen the possibility that the wall will experience such loads in service. If that is the case, then the wall design will need to take account of those loads too - which is a huge unstated requirement.

I think Jboggs has a point.

A.

 

[BUGGAR]

"again I'm a electrical Engineer that is filling the mechanical engineer position due to the fact that he got lay doff"

So we're filling in for the laid off M.E.? I had some ideas but think I'll pass.
G'luck.

 

[btrueblood]

My advice would be to hire somebody to replace the guy that was laid off.

 

[aghaderi]

Hi Jboggs:

Thanks for your reply, I fully understand this, I will not even get close to do any prototyping or designing a mechanical fixture like this , I am clearly not an candidate for this. I totally understand this. I just wanted to get an idea that what are the choices on the table until we find another Mechanical Engineer. Again am not a "ME" and I will not put my self as an ME. I do realize that this project has to be done by a professional ME and I totally respect that (I wont stick my noise to anything that I don't know about). Again I wanted to get some general idea that how this thing will be designed roughly so I could see what kind of electronics I would be working or I will be expected to work on. sorry for the misunderstanding.

 

[IRstuff]

"That's a possibility, but if I want to do the FDA failure Test, which is pushing a Small part out by force how are we going to place another part in between immediately"

I'm not understanding; isn't the objective is to not fail the test unless it's at some absurdly high force level? Then the question of replacing parts is mote. Nevertheless, it would seem plausible that one could make the scales one-sided, i.e., resist force from one side, but be easily removable from the other side.

TTFN
I can do absolutely anything. I'm an expert!
homework forum: //

http://www.engineering.com/AskForum/aff/32.aspx

faq731-376 forum1529

 

[3DDave]

" if I want to do the FDA failure Test, which is pushing a Small part out by force how are we going to place another part in between immediately?"

The FDA won't require an infinite amount of force. There will be a limit, assuming you have a traceable requirement (which I mean, you have a link to the FDA requirement for the rest of us to read), and it's possible to have a wall stronger than that.