Posted By llynrice on 05/22/2008 8:12 PM

Hi Dwight,

For the original for a cylinder with a 1" bore and 1" length, the force trying to break the cylinder open at 100 psi would be 100 pounds force. If you section the cylinder lengthwise, the total cross sectional area of the walls would be (1/4" x 1") + (1/4" x 1") = 0.5 square inches. Divide the 100 pound force by the area and the tensile stress is 200 pounds per square inch. I don't know what bronze alloy you have; but, Machinery's Handbook shows a yield strength ranging from 20,000 to 50,000 pounds per square inch. Even if you cut the wall thickness in half - yielding a stress of 400 pounds per square inch, it would appear that you have a really significant factor of safety. My calculations are somewhat simplified; but, give a notion of what you are working with.

Keep in mind that screw holes drilled into the walls to keep the end caps in place will weaken the cylinder some as well.

Llyn

Sorry, can't agree with your calculations.

Assume a cylinder with 1" bore and 1" stroke. Also assume a force of 100 psi.

Area of the top (and bottom) of cylinder = pi*r*r = 3.1416 * 0.5 * 0.5 = 0.7854 square inches x 2 (for top and bottom) = 1.5708 square inches.

Now add the sides. The area = 2*pi*r x length = 3.1416 square inches.

Total area = 1.5708 square inches + 3.1416 square inches = 4.7124 square inches x 100 pounds/square inch = 471 pounds of pressure pushing on the interior of the cylinder. But you are only concerned with the walls, so 3.1416 x 100 pounds/square inch = 314 pounds of pressure on the walls.

As to the 20,000 - 50,000 PSI for bronze, something is missing here (like wall thickness). "Square inches" has only two dimensions and fails to consider the thickness of the walls. Certainly a sheet of bronze foil (the thickness of Reynolds Wrap aluminum foil), would not hold 20,000-50,000 psi. /DesktopModules/NTForums/themes/mls/emoticons/pinch.gif"