Re: OT: Tensile strength of steel

On Aug 28, 10:48 pm, Tim Wescott <t...@xxxxxxxxxxxxxxxxxxxx> wrote:
On Thu, 28 Aug 2008 19:05:04 -0700, linnix wrote:
This is not really electronics, but most of us are engineers here.
Right?

I need to estimate the tensile strength of a steel bar of 25mm width and
1mm thick.

Do I have the numbers correct?

Using low end estimate of 400MPa steel.

400 MPa = 400,000,000 Newton / sq. meter

25mm x 1mm = 0.025 * 0.001 = 0.000025 sq. meter

400,000,000 * 0.000025
= 10,000 Newtons or 2250 pounds (4.4 pounds per Newton?)

The math looks right. Steel only gets to it's ultimate strength in a
laboratory -- in real life it always fatigues, or buckles, or does some
other real thing that the math doesn't cover well.

Figure that if it's going to rust or be subject to repeated stress that
you need to derate that calculation by at least a factor of 10 -- and
don't take my word for it, I'm just a gearhead, not a mechanical engineer.

It's stainless steel screwed on a piece of wood to increase the
tensile strength of the structure. It could be subject to a few
hundred pounds of vibrations, but no where near 2000 pounds. I just
need to figure out if it should be 1mm or 2mm thick.
.

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