Browse Publications Technical Papers 2005-01-2273

Measurement of Torsional Natural Frequencies, Moments of Inertia and Torsional Stiffness of Shafts 2005-01-2273

This paper presents a method to measure torsional natural frequencies and to calculate moment of inertia and torsional stiffness of a shaft. The concepts of equivalent mass moment of inertia and equivalent torsional stiffness are used to model the shaft. The method applies two identical accelerometers to measure the frequency response functions (FRFs) on two symmetric positions about the shaft. Adding these two FRFs, the bending components of the FRFs are canceled, whereas the torsional components of the FRFs are retained and enhanced. Hence, the torsional natural frequencies of the shaft can be found. By attaching a uniform hollow disk firmly to the free end of the shaft and measuring the new FRFs of the system with the disk, the moment of inertia and torsional stiffness of the shaft can be calculated.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 43% off list price.
Login to see discount.
Special Offer: With TechSelect, you decide what SAE Technical Papers you need, when you need them, and how much you want to pay.