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to visualize the dynamic character of a set of designs. Note that Ux, Uy and Uz are useful but not a predictor of actual deformation. I trend u across studies. I also trend the algebraic sum of u and track how far off of a goal it is. A goal of zero is popular since that would mean something like dynamic symmetry, of course depending on the geometry and the industry. Mine is loudspeaker driver design so non-axisymmetric moving mass dynamism is predicted by modal analysis.
A common use of Frequency Analyses are to compare the natural, or resonant, frequencies of a part or assembly to the input frequencies. The example I like to use is a grinding wheel in the shop. It usually sits on a steel frame bolted to the floor. Most people have noticed that after turning the motor on and as the wheel accelerates to operating speed, the stand shutters and vibrates, then settles down. The wheel speed (RPM) just passed thru the first natural frequency of the stand, causing it to resonante and vibrate. When the wheel speed increased past that natural frequency, the stand stops shaking. It would be important from a desinger standpoint, to make sure that the 1st natural frequency of ths stand wasn't the operating speed instead of some intermediate speed since the stand wouldn't be usable and would shake itself to death.
Does this make more sense?
Thank You very much Vince & Genexxer.......
Both of your explanation is very useful for me.