NCEES #533 on 2008
Posted 12 April 2012 - 07:06 PM
Anyone?? Where do they get the damping ratio of 0.5 even?
Posted 12 April 2012 - 07:48 PM
A 24 inch diameter rotating drum is part of a machine that weighs 1 ton and will operate at 10,000rpm. The balance specification calls for an unbalance no greater than .3 oz-in. There are vibration isolations mounts on each of 4 corners of the platform supporting the machine. The system has a natural frequency of 17hz, and damping has been chosen as half the critical damping value.
Unknown to anyone during installation a 1/2lb bolt was left inside the 24" diameter drum of the machine. assume friction causes the bolt to act as if it were attached to the rotating drum. The max displacment amplitude of the steady -state response occurse at a frequency (as a percentage of the natural freq) that is most nearly:
Posted 12 April 2012 - 08:54 PM
Posted 12 April 2012 - 09:13 PM
0 user(s) are reading this topic
0 members, 0 guests, 0 anonymous users