Design of a column for machine

[koushik123]

Hello everyone

I am designing a machine which has got two cylindrical hollow aluminum columns on its either side to hold the machine.For better understanding , I have attached a picture of it below.

My question is

A side load of around 1500 N acts on the column radially at half of its height. For a factor of safety of 3, How to determine the dia of the column?

The height of the column is 2000 mm

Thanks in advance

 

[desertfox]

Hi
Does this side load occur on each column at the same time?
Assuming for a moment it does I would treat the column as a beam using the bending moment formulae to obtain the stress.

Just looking at your picture how is the base held down because where the two columns are situated there appears to be no fixings, if the fixings are on the opposite side then you need to check the stress in the bolts due to the bending generated by the 1500N.

 

[SnTMan]

I'd guess you would be more interested in deflection that stress.

Regards,

Mike

 

[ades]

I would consider it as a beam, and calculate also the reactions at the supports. May be you can also calculate the deflection in the middle point.

 

[drawoh]

koushik123,

This looks to me to be a analysis problem, clearly explained in your mechanics of materials and your machine design textbooks. This should be simple to solve, once you define your failure modes.

Am I missing something?

--
JHG

 

[boyze]

looks like a test machine or similar. a few questions to consider:

will there be other loads coincident with the side force like a vertical column load?

is the side force a point load on the hollow column with it's own local stresses in combination with the global stresses?

is the factor a safety on Fty, Ftu, fatigue, buckling, machine overturning.....?

as others mentioned there are potential bolts/fasteners/welds that maybe in play?

same for bearings, bushings.....?

if it is a test machine then flexibility and/or frequency response (if dynamic) maybe a consideration.

Have Fun!

James A. Pike

http://www.xl4sim.com

http://www.erieztechnologies.com

 

[dhengr]

Koushik123:
It is a good thing that you posted the picture, because I’m not sure that anyone would have drawn that machine from your description (word picture). Isn’t that a tension or compression testing machine, but I don’t see what powers it up or down? I would assume the two columns (one on each side) are cantilevered out of the base, and that for the most part the columns would see axial loads, either tension or compression. Aluminum columns may not be your best choice, aluminum is not a good running bearing surface. Are you actually talking about a lateral load on the columns, shared by the columns, at some mid height btwn. the base structures and the top (head, cross member) structure. What causes this lateral loading? In this case the columns would be cantilevered beam-columns. And, your Strength of Materials or Theory of Elasticity text books should be helpful, as Drawoh suggested.

 

[koushik123]

Thank you for your valuable replies gentlemen