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structure dimension 6
- Thread starter ash1982
- Start date
- Thread starter
- #3
no this for work project, i'm desiging a base frame for a welding manipulator, the base frame will be made out of mild steel. i've looked for information all over the web but struggled to find what i'm looking for so if you can help i'l be very greatful
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EngineerTex
Mechanical
Change your file to a .jpg. I (and probably most people on here with sense) don't open zip files.
When you talk about deformation, are you talking about permanent deformation? Or are you looking for something that doesn't deflect at all? (If so, then you you should use a tempered alloy that was quenched in unicorn tinkle.)
Without looking at your model, you probably need to look at
I assume you have some sort of tube (rectangular, round or square) that is holding *something* and you need to know how thick to make the wall. If that's the case, then you really need to contact someone in your organization that is capable of doing this. Even consider an outside consultant. Nothing wrong with asking, but I think you will find a lot of people responding to your post with the very wise advice of seeking professional help on this one. My big concern for this is that you're talking about a manipulator which can/may(?) impose some very serious dynamic loads on whatever type of base that you're trying to design. Merely taking into account weights and offset loads can end up killing people. That means YOU go to jail.
As I said, I didn't look at your file, but I think you are in over your head. Get someone to help you on this.
Engineering is not the science behind building. It is the science behind not building.
When you talk about deformation, are you talking about permanent deformation? Or are you looking for something that doesn't deflect at all? (If so, then you you should use a tempered alloy that was quenched in unicorn tinkle.)
Without looking at your model, you probably need to look at
I assume you have some sort of tube (rectangular, round or square) that is holding *something* and you need to know how thick to make the wall. If that's the case, then you really need to contact someone in your organization that is capable of doing this. Even consider an outside consultant. Nothing wrong with asking, but I think you will find a lot of people responding to your post with the very wise advice of seeking professional help on this one. My big concern for this is that you're talking about a manipulator which can/may(?) impose some very serious dynamic loads on whatever type of base that you're trying to design. Merely taking into account weights and offset loads can end up killing people. That means YOU go to jail.
As I said, I didn't look at your file, but I think you are in over your head. Get someone to help you on this.
Engineering is not the science behind building. It is the science behind not building.
IceStationZebra
Mechanical
You need to specify what is causing the deformation. Machining, welding, normal in-use loads, etc.
ISZ
ISZ
- Thread starter
- #6
thanks alot for your time and effort,
i have included a jpeg file with this so you can have a look at it. what i need to find is permanent deformation and the fixture will only have 200 kg resting on top of it in any case. thanx again for your time
i have included a jpeg file with this so you can have a look at it. what i need to find is permanent deformation and the fixture will only have 200 kg resting on top of it in any case. thanx again for your time
EngineerTex
Mechanical
How is it going to be held to the ground?
In the detail you show there, it appears that the upper horizontal member is butted up against the two vertical members and furthermore, the two vertical members extend higher than the horizontal support.
Because of this, you do not have an adequate moment connection between the members. If you assumed this as having restrained ends, you would get a certain amount of fixity between the two parts, but in reality, the vertical member would "oilcan" *out* at the upper weld and *in* at the lower weld of the connection of the horizontal support. So, unless you change that portion of the detail, you should probably calculate it as a simply supported beam with a load in the center.
What kind of steel are you making this out of? If it is 40mm sq tubing, then you're probably building this in Europe. If that's the case, then assume a simply supported beam, add any torsion due to offset of load, determine your required section modulus (including the correct safety factor) and find your corresponding tube size from the tables here:
The tubes you can obtain most easily in western Europe should conform to EN 10210:S355.
Engineering is not the science behind building. It is the science behind not building.
In the detail you show there, it appears that the upper horizontal member is butted up against the two vertical members and furthermore, the two vertical members extend higher than the horizontal support.
Because of this, you do not have an adequate moment connection between the members. If you assumed this as having restrained ends, you would get a certain amount of fixity between the two parts, but in reality, the vertical member would "oilcan" *out* at the upper weld and *in* at the lower weld of the connection of the horizontal support. So, unless you change that portion of the detail, you should probably calculate it as a simply supported beam with a load in the center.
What kind of steel are you making this out of? If it is 40mm sq tubing, then you're probably building this in Europe. If that's the case, then assume a simply supported beam, add any torsion due to offset of load, determine your required section modulus (including the correct safety factor) and find your corresponding tube size from the tables here:
The tubes you can obtain most easily in western Europe should conform to EN 10210:S355.
Engineering is not the science behind building. It is the science behind not building.
- Thread starter
- #8
For the top horizontal beam only, you can calculate shear, moment, and torsion (if any) using beam formula, then check it against the allowable stresses for the metal in construction. The most straight forward method is to assume an initial wall thickness to obtain relevant member properties, calculate stresses, and perform iterations to get minimum thickness required to satisfy the stress limitations.
After you get the wall thickness, you can use beam formula to calculate displacement under the force. You can get all formula from an engineering handbook, or from the web.
After you get the wall thickness, you can use beam formula to calculate displacement under the force. You can get all formula from an engineering handbook, or from the web.
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Hi ash1982
Are you intending to make the whole frame out of plate and fabricate box sections?
How do you attach your device to the structure assuming its all fabricated box section?
I would suggest if you want to fabricate sections then fabricate small "I" beams see attached sketch.
Analyse as a simple beam and you can take proportions of plate thickness for flanges and webs from standard beam sections found at this site:-
also you can calculate the stresses from the beam theory from the same site but a different link:-
Your going to have to guess a size for your "I" beam in terms of depth and width and run some calculations, if it doesn't work try again with a different section.
I suppose one difficulty might be the 40mm width unless you can change it.
Are you intending to make the whole frame out of plate and fabricate box sections?
How do you attach your device to the structure assuming its all fabricated box section?
I would suggest if you want to fabricate sections then fabricate small "I" beams see attached sketch.
Analyse as a simple beam and you can take proportions of plate thickness for flanges and webs from standard beam sections found at this site:-
also you can calculate the stresses from the beam theory from the same site but a different link:-
Your going to have to guess a size for your "I" beam in terms of depth and width and run some calculations, if it doesn't work try again with a different section.
I suppose one difficulty might be the 40mm width unless you can change it.
EngineerTex
Mechanical
You've also got to take into account buckling on the vertical members.
desertfox, there will be no welding on this. What you see in the .jpg is just a single piece of 40mm plate, cut out on a cnc. The term "wall thickness" should actually be "member depth."
ash1982, I would suggest you look around a parking lot at the rear bumpers of a lot of larger vehicles. You will see 50mm x 50mm square tube being used as the structural member of receiver hitches. I have attached a picture. It's the part in black.
Look at that picture, remember that these items are designed to pull 5000 pounds and handle heavy acceleration, braking, potholes, overloaded trailer tongue weights and severe abuse by a generally uninformed public and still hold up. This is a 50mm x 50mm section that is hollow in the middle. Take that for what it is -- an observation -- and try to extrapolate it into your application.
Beyond that, I don't think I can help.
Engineering is not the science behind building. It is the science behind not building.
desertfox, there will be no welding on this. What you see in the .jpg is just a single piece of 40mm plate, cut out on a cnc. The term "wall thickness" should actually be "member depth."
ash1982, I would suggest you look around a parking lot at the rear bumpers of a lot of larger vehicles. You will see 50mm x 50mm square tube being used as the structural member of receiver hitches. I have attached a picture. It's the part in black.
Look at that picture, remember that these items are designed to pull 5000 pounds and handle heavy acceleration, braking, potholes, overloaded trailer tongue weights and severe abuse by a generally uninformed public and still hold up. This is a 50mm x 50mm section that is hollow in the middle. Take that for what it is -- an observation -- and try to extrapolate it into your application.
Beyond that, I don't think I can help.
Engineering is not the science behind building. It is the science behind not building.
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The OP states that the sketch is for a base frame.
Is this just a frame (base) to hold single column manipulator?
If not the above and just looking at initial and subsequent sketches, I think the use of the phrase welding manipulator is misapplied as the frame depicted would be more suitable for a welding positioner. All welding manipulators that I'm acquainted with are composed of single column with a radial arm or gantry to carry the welding head. If this is indeed for a positioner the loadings would be very high and complex.
Welding manipulators>
Is this just a frame (base) to hold single column manipulator?
If not the above and just looking at initial and subsequent sketches, I think the use of the phrase welding manipulator is misapplied as the frame depicted would be more suitable for a welding positioner. All welding manipulators that I'm acquainted with are composed of single column with a radial arm or gantry to carry the welding head. If this is indeed for a positioner the loadings would be very high and complex.
Welding manipulators>
Has anyone here heard of a structure that doesn’t deflect when loaded? Please tell us and explain. There is no simple beam in the pictures or sketches shown. Does anyone here think it’s strange that we are trying so hard to respond to a question which is so ill asked that we don’t know what to suggest. Does anyone other than EngineerTex (2JAN10, 17:07) and me think this guy could kill someone, and we are helping, aiding and abetting him. What he should do is get a good strength of material text and a good structural design text and learn his trade so he can at least ask a less dangerous question.
- Thread starter
- #14
a lot of appreciation to everyone who tried to help me solve the matter. I'm really sorry about the unclear explaintion of what is required.
dhenger i'm not looking for a structure that does not deflect when loaded, i'm looking for a mimiumum structure that can take the vertical load without any permenant deformation (Plasticity) thanx for you concern anyway.
dhenger i'm not looking for a structure that does not deflect when loaded, i'm looking for a mimiumum structure that can take the vertical load without any permenant deformation (Plasticity) thanx for you concern anyway.
Hi ash1982
It would help if you can tell us exactly what this frame is going to have attached to it.
A 40mm wide structure as we see it doesn't look very stable on its own.
Can you tell us how the frame will be held vertical and why its only 40mm wide, also how do you intend to fasten anything to it.
We are trying to point you in the right direction is there anyone you work with that could help you also?
desertfox
It would help if you can tell us exactly what this frame is going to have attached to it.
A 40mm wide structure as we see it doesn't look very stable on its own.
Can you tell us how the frame will be held vertical and why its only 40mm wide, also how do you intend to fasten anything to it.
We are trying to point you in the right direction is there anyone you work with that could help you also?
desertfox
- Thread starter
- #16
H ash1982
Thanks for the pic it does help but how is the frame attached to the other parts ie bolted, welded?
Also the geen coloured structure that rests on the frames are the attached in anyway and are they running at the centre of the frame or to either side of centre.
desertfox
Thanks for the pic it does help but how is the frame attached to the other parts ie bolted, welded?
Also the geen coloured structure that rests on the frames are the attached in anyway and are they running at the centre of the frame or to either side of centre.
desertfox
- Thread starter
- #18
Thanks desertfox for your intreset. The frame is bolted to the manipulator via 12 mm bolt. The Green coloured structure (Boom) sits on the center of the frame between the two vertical members of the frame. the Boom will also be secured down to the frame by the use of adjustable block.
EngineerTex
Mechanical
ash1982, this is far worse than I thought. Just looking at your sketch, it looks like the structure (boom) that you're supporting is a very heavy (400kg) and quite unbalanced load.
Think about this for a second: when you stand on a diving board, the support next to the pool is in compression and the support farthest from the pool is in tension. Apply that to your model: one of your supports is likely to be loaded to well over 400kg and the other one will probably be in tension. You need to figure out the center of gravity of your boom and apply that information to your structure.
Furthermore, it appears that a portion of the assembly rotates. Is that correct? Does it rotate about the axis of the centers of the two supports? This fact makes it much more complicated than you first stated. What happens when you turn the boom through a few degrees and the loading is now bending your "vertical" members? Are you sure that the base is fixed to the ground well enough to prevent overturning of the entire assembly?
You ABSOLUTELY MUST call an outside consultant.
Engineering is not the science behind building. It is the science behind not building.
Think about this for a second: when you stand on a diving board, the support next to the pool is in compression and the support farthest from the pool is in tension. Apply that to your model: one of your supports is likely to be loaded to well over 400kg and the other one will probably be in tension. You need to figure out the center of gravity of your boom and apply that information to your structure.
Furthermore, it appears that a portion of the assembly rotates. Is that correct? Does it rotate about the axis of the centers of the two supports? This fact makes it much more complicated than you first stated. What happens when you turn the boom through a few degrees and the loading is now bending your "vertical" members? Are you sure that the base is fixed to the ground well enough to prevent overturning of the entire assembly?
You ABSOLUTELY MUST call an outside consultant.
Engineering is not the science behind building. It is the science behind not building.
- Thread starter
- #20
engineerTex, i've already made sure that the Center of gravity of the Boom is located in the center of the fixture to make sure that the load is balanced, this is why i stated that the height of the supporting frame has to be (264 mm. thanks for your guidance and i'l have to consult some one about it.
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