I am trying to estimate tensile strength of different materials. Basically, if i drill two 1/4 holes on a sheet and pull it apart, at what point will it break?
Assuming 50,000 PSI for steel and 10,000 PSI for 1/4" plastic:
16 ga: 50,000 / 16 = 3000 pounds 1/4" plastic: 10,000 / 4 = 2500 poundsIs that corretc?
Why drill holes?
-- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
Should i multiple the width of the sheet and divide the diameter of the hole:
I.e. For 12" sheet with 1/4" holes:
16 ga: 50,000 / 16 * 12 / 4 = 1000 pounds 1/4" plastic: 10,000 / 4 * 12 / 4 = 800 pounds
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.
-- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
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
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Sideway stress. Washer won't matter.
Of course will test it, but trying to estimate first.
I guess there are two issues:
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
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
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.
-- Jasen.
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