Design of a single axle water bowser ( to use for agricultural purposes) 2

[chaser88]

I have to design a single axle agricultural water bowser using manual calculation. Can someone guide me about how to start. Which calculations need to be done and can you please suggest me a specific standard which I can use for the design process? Kindly find an example picture of a typical water bowser.

 

[racookpe1978]

Seems like you need to begin with your own specific research.

First, why can YOU not look up the problems with ag water trucks on line? A one axle water tank is a very, very poor requirement to begin with! It needs to be propped up every time the tank is disconnected, is unstable, and will tend to sink into the loose soil or mud, since it has half the tire area of a two-axle double trailer.

 

[LittleInch]

Calcs?

How about;
Size,
Weight
Axle location
Centre of gravity
Axle load
Tyre size and width
Wheel load
Ground bearing pressure
Type of material
Round, square, oblong, hexagonal, vertical cylindrical, horizontal cylindrical??

Picture? Never heard of google images?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[chaser88]

The single axle water bowser which I am talking about is one which should be hitched to a tractor and used for watering purposes. Normally it will be a horizontal cylindrical tank which will be mounted permanently on trailer. I understand that first of all i need to consider about the maximum load which the axle and trailer can support and based on that i can think about the volume and weight of cylindrical tank which i can put on the top.
I would like to know how actual designers proceed with the design of such type of water bowser. Do they use a specific standard (like ISO or ASTM)???

 

[racookpe1978]

No.

Designers BEGIN with their customer's requirement, the legal and moral issues involved (safety, regulatory codes and local laws - those where the piece is going to be made and and where they are going to be used, the limits of what their customer(s) want/can afford/need/would like to have.

No sales = No money = no material = no purchase = no work.

THEN, the designer starts evaluating limits and material requirements.
Then, the designer finds the limits of his/her material (tires size, bearing weight, material strengths, axles width or trailer lengths or tractor pulling limits)....

 

[chaser88]

@racookpe1978 How about the limits of material!! Do designers extract these information from specific standards or do they make use of any Standards during the design procedure. For instance there is a specific height which a water bowser needs not exceed. Is that height available in any standard!!
For the case of Road tankers for light petroleum products there is standard for its specification like tank capacity,materials, thichkness of metal, design pressure and so on.
But what about a single axle agricultural bowser?? Is there any standard for its specification?

 

[Artisi]

Your best bet would be to pickup the local phone book and get the number for the local agricultural equipment supplier. Check price, availability and ordering procedure.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[JStephen]

I have seen some similar issues come up with bicycle design, dump trailer design, etc.
The problem is this: Given a set of forces acting on a frame, axle, etc., it is fairly straightforward to design the structure for those forces.
But in the case of a moving vehicle, those forces are unknown.
Given a particular road configuration, it would be possible (though more complicated) to come up with those forces.
But in the case of a moving vehicle, that road configuration is unknown.
The thing is, people don't normally design stuff like this starting from scratch, they start by using the last 50 years of industry experience that their company has been engaged in.
So I'm not aware of any Trailer Standard 101 that says, "Thou shalt design the axles for 179% of static load, and then it's good for any pothole you'll ever encounter." Which is really what you're looking for.

That being said, you might start looking into axle sets available - the one dump-trailer project I observed, they just bought the major components, they didn't start machining axles or anything.

 

[LittleInch]

chaser88,

I think you're looking for something which doesn't exist.

A simple search on something like "agricultural bowser design" shows many results, but no mention of complying with XYZ spec or standard.

Judging by this

http://www.bowsersupply.co.uk/products/

the design is very much based on experience and how much someone wants to pay. Many seem to be converted milk tanks placed on the frame of a trailer.

If you're going to use it on the public highway, most countries will have various regulations about weights, braking, lights etc, but from my experience farmers take a fairly relaxed attitude to whatever they drag around behind their tractors....

Can't wok out why you're starting from first principles here, there are many many suppliers who have been doing this for decades and know what works and what doesn't work, without feeling the need to sit down and write it into a technical document.

probably best to call one of them or drop round and see one and see what they have to say.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[racookpe1978]

Sure.

To be blunt:

"The top of thy bowser shall be lower than the height of all barn doors through which thy bowser shall be placed."
"The length of thy bowser shall be less than the length of any barn into which thy bowser be placed with the barn door shut."

See? We don't know enough of your specific problem to do much more than make guesses: And we KNOW those guesses don't help you very much and are irritating.

We HAVE to be irritating you, because if I said "14 feet max height to fit under interstate highway bridges" ... but you were thinking of a farm assembly that needs to go under a 12 foot barn door (or my Uncle Tom's 8 foot door, or your 10 foot, or 2.5 meter shed roof, or the 6 foot high culvert/cow path bridge) I'd be just as wrong.

A one-of-a-kind assembly used on your property frankly doesn't need to be "designed" from scratch using theoretical metal strengths from a Code. It needs to be built from your materials at hand using your best judgement, then tested. The errors you make increase your judgement for the next time. There really isn't any penalty for failure other than your re-work and your own individual safety. BOTH your materials and your safety ARE expensive, but you are liable for both rather than elegant theories that require elegant fabrication techniques and xray'ed welds and additional unknown safety factors and margins. (If the axle is "too strong" because you salvaged it from a used haybailer, the axle is still "good enough" and far better than a custom designed exact to fit axle that fails when you get stuck in mud "gummier" than the dry field you expected.)

A four unit production run for each of your neighbors is different.
A four hundred unit production run commercially built is different.
A 40,000 unit production run is different.

 

[IRstuff]

Is this for school? Otherwise, why is there a requirement to do manual calculations?

For a typical engineering development, you start with a functional and performance specification, which you seem to be lacking. Typically that specification will call out all relevant codes and specifications that the product must adhere to. Seems to me you should ask your instructor.

TTFN
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