Question for materials engineers re. polycarbonate

Sycho15 · #1 10-08-2006, 07:31 PM

In the mechanical properties of polycarbonate, it has listed a 12,000psi compression strength.

How do they determine this figure? What are the dimensions of the tested piece?

Most specifically, I would like to know what thickness a (flat) 4'x8' sheet would have to be to withstand 250psi and 500psi without significant deformation.

savage3c · #2 01-20-2007, 11:27 PM

Not a materials engineer, but did work for Penn Central Research Center back in 1970.

We took a standard rail passenger car window frame and installed 3/8 inch LEXAN in it...

Supported on blocks and dropped bricks on it with nothing more than a bounce.

Tried shotgun and it stopped the slug. Same with large caliber handguns, but 22 went straight through.

Can't relate to your 250 or 500 PSI figures but thought this data might give you a little clue as to how good polycarbonates are.

We finally did dislodge it from the frame by dropping a brick off a 2 story building on the window.

83GMCK2500 · #3 03-02-2007, 11:14 PM

Quote:

Originally Posted by Sycho15

In the mechanical properties of polycarbonate, it has listed a 12,000psi compression strength.

How do they determine this figure? What are the dimensions of the tested piece?

Most specifically, I would like to know what thickness a (flat) 4'x8' sheet would have to be to withstand 250psi and 500psi without significant deformation.

Might try looking for an ASTM chart on the material in question. It should tell you the dimensions of the sample. You'll want to know the maximum bending stress and maximum shear stress to begin with.