Generator) in Appendix E of TID-7024? I reworked the problem using
Excel for the arithmetic and I'm finding some fairly significant
errors, some of which are likely due to the slide rule precision used
when the problem was first laid out and others which look like some
other numbers possibly mixed in from another problem or another
version of the same problem. For example one of the two calculated
natural frequencies seems to change from 80.6 rad/sec to 79.8 rad/sec
and the other goes from 897 rad/sec to 932 rad/sec. at the end. Since
the problem was carried through in length units of feet, the
calculated displacement of 0.00047 ft is converted to 0.0056 inches,
like you'd expect, but a rotation of 0.000212 radians also gets
multiplied by 12 to get 0.0025 radians, which is a bit squirrelly.
The 'converted' angular displacement gets carried into a calculation
of the maximum overall displacement of 0.144 inches which isn't right.
Is anyone aware that these errors exist? This isn't a particularly
urgent situation, since I'm using it as an exercise in a tutorial I'm
putting together, but I'd be grateful if anyone has any background on
possible errors.
Christopher Wright P.E. |"They couldn't hit an elephant at
chrisw@skypoint.com | this distance" (last words of Gen.
.......................................| John Sedgwick, Spotsylvania
1864)
http://www.skypoint.com/~chrisw/
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