Tensile strength

Why drill holes?

Should i multiple the width of the sheet and divide the diameter of the hole:

I.e. For 12" sheet with 1/4" holes:

For supporting brackets, the point is to estimate how strong they are.

I'd expect the situation to be far more complex than your math suggests. What goes in the holes? Rods? Bolts? Bolts with washers? How much wider than the holes is the material?

Better to test and derate.

The geometry is too complicated. There will be a stress concentration at the sides of the holes, which will lead to cracking as the metal deforms. Also there are a few parameters that are loosely called 'tensile strength': Young's modulus, yield stress, and ultimate tensile stress.

There are calculators available on the web for this, I think.

Cheers

Phil Hobbs

Sideway stress. Washer won't matter.

Of course will test it, but trying to estimate first.

I guess there are two issues:

1. The 1/4 hole start to tear

1. The 12" sheet tear apart

OK, i guess washer matter, like John said.

Where?

It's way more complex than the above calculations indicate.

Start with: .

But also see the various steel design handbooks for the nitty-gritty practical details.

Joe Gwinn

If you intend to drill holes, and insert pins to take the load, it's not TENSILE strength that limits you, it's COMPRESSIVE strength, as the material crushes against the force-taking pins. The high stress points, like those pins, are the breaking points (and fatter holes for the pins lowers the stress, if you fit fatter pins in those holes)

Perhaps both compression and tensile. Tensile strength is what's keeping the materials to tear apart.

Yes, that's what i am trying to figure out. How many bolts and what sizes.

for one.

Cheers

Phil Hobbs

usually near the holes :)

This is stuff you can look up. I think that by volume most plastics are weaker than most steels.

The arithmetic seems sound you archaic units are meaninless to me.