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Old January 07, 2013, 22:09   #81
FALaholic #: 62696
Join Date: Jan 2011
Location: SE Michigan
Posts: 76
"This is a .308 caliber 1.25" to 0.9" diameter straight taper stainless steel barrel 22" long with the action end fixed. You are looking at the muzzle end and it is tilted down slightly for better viewing. These are the first 8 mode shapes and frequencies. Each bending mode (like Mode #1) is on one plane, but there was another identical mode in another plane at the same frequency that was not shown to save space. The torsional modes #4 and #8 are at a high frequency. I should have printed the mesh lines on the torsion modes so one could see the rotation. Note, modes 1, 2, 3, 6, and 7 are shown in a single plane, but can exist in other planes. Modes below a frequency of about 500 Hz will not be able to complete one full cycle before the bullet exits the barrel."

Mode 1 82hz
Mode 2 406hz
Mode 3 1050hz
Mode 4 1756hz
Mode 5 1984hz
Mode 6 2485hz
Mode 7 3180hz
Mode 8 4171hz

Close up of mode 8 (torsion mode)

Things are never as simple as they seem...
westcliffe01 is offline   Reply With Quote