From {HEAD ~ a comparison} of {TAIL ~ the vibration spectrum} of the flexural mode and the vibration spectrum of the torsional mode , it can be observed that more high harmonic force components are excited in the torsional mode with better signal to noise ratio 
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From { HEAD ~ a comparison } of { TAIL ~ the vibration spectrum } of the flexural mode and the vibration spectrum of the torsional mode , it can be observed that more high harmonic force components are excited in the torsional mode with better signal to noise ratio
OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH