Thickness of material to support a heavy load

malek340

My situation is i have a 10kg battery that is mounted on top of a plastic material. How would i exactly calculate the right thickness for the plastic to support the 10kg battery?

huntoon

first you need to know what the other two dimensions are. the third dimension - it's thickness- will be dependent on them.

second, you need to describe the exact type of plastic.

malek340

Other two dimensions?

Travis_King

The length and width of your peice of plastic (along with the locations of any supports) will dictate the thickness required to support the load.

The type of plastic, as well, will be a required known.

Studiot

Personally I'd go for some glass fibre reinforced plastic or perhaps steel mesh reinforced.

A sheet up to 400mm x 400mm x 5 mm thick would readily take a 10Kg point load if supported on two or four edges.

Is this for a boat or car?

malek340

What if i were to use syntactic foam for the base to support the load?...Give me your thoughts anyone..

huntoon

dude, it really depends. how accurate do you need to be? how important is that accuracy?

you need an exact material spec to start. then you need to model the 3 dimensional structure.

the basic strength analysis would be to determine thickness by strength necessary for a given cross section.


i mean who knows about this foam? it could be super strong in tensile but super weak in yield or compression.


you could always run tests of varying thickness foam. it would super awesome if you documented the process and and posted links or info here.

Studiot

What if you did?
What would you then support that on?

Travis_King

Or you could just by a piece of really thick plastic. It's not that expensive. There's no sense modelling it, jut build it bigger than it needs to be.

malek340

Do u have any formula to calculate the thickness needed?

zero_delta

google "strength of materials + bending stress" and youll see equations like:

E = (P*L^3)/(4*w*y*t^3)

For E you can use modulus of elasticity. P is the load, L is the length, w is the width, t is the thickness and y is the deflection or bending. Look up E, solve for t.

malek340

By p/load, you meant the force or the weight of the load and the length and with is of what?

zero_delta

For P use weight. I prefer SI units and in this case it would be 10kg * 9.8 m/S^2 or 98 N.

The dimensions (L, w, t) are for the plastic or whatever supporting material you wish to use.

malek340

Thank you very much!

malek340

Hey bro, but by Y, what does it mean by deflection at load point?? Sorry, i need to know this

zero_delta

While considering the center of mass of the battery to be the load point, and the battery would be on the center of the supporting material, y is the maximum amount of bending from a neutral flat position.

These types of equations are great, but this is just about as simple as they get. The expression I gave is for a highly idealized and restricted situation.

Studiot

Bear in mind, zero delta, that the OP has already been asked about the available supports without response.