Dynamic instability of supercritical driveshafts mounted on dissipative supports—Effects of viscous and hysteretic internal damping

Abstract

The case of a rotating shaft with internal damping mounted either on elastic dissipative bearings or on infinitely rigid bearings with viscoelastic suspensions is investigated in order to obtain the stability region. A Euler-Bernoulli shaft model is adopted, in which the transverse shear effects are neglected and the effects of translational and rotatory inertia, gyroscopic moments, and internal viscous or hysteretic damping are taken into account. The hysteretic damping is incorporated with an equivalent viscous damping coefficient. Free motion analysis yields critical speeds and threshold speeds for each damping model in analytical form. In the case of elastic dissipative bearings, the present results are compared with the results of previous studies on finite element models. In the case of infinitely rigid bearings with viscoelastic suspensions, it is established that viscoelastic supports increase the stability of long shafts, thus compensating for the loss of efficiency which occurs with classical bearings. The instability criteria also show that the effect of the coupling which occured between rigid modes introducing external damping and shaft modes are almost more important than damping factor. Lastly, comparisons between viscous and hysteretic damping conditions lead to the conclusion that an appropriate material damping model is essential to be able to assess these instabilities.

Steady-state and transient responses of a flexible eccentric spinning shaft

“…In steady state whirl, the supplied mechanical power is equal to the dissipated power, i.e., W m = W d [21,22].…”

Optimisation of hybrid high-modulus/high-strength carbon fibre reinforced plastic composite drive shafts

“…Rolling-element bearings provide insufficient damping. Dissipative materials such as elastomers have recently been used as bearing supports as a passive means of enhancing the non-rotating damping [17,18]. A low cost configuration consisting of an axisymmetric composite shaft simply supported on classical rolling-element bearings mounted on viscoelastic supports was studied here ( Various approaches based on beam and shell theories have been used to compute the critical speeds of composite shafts [19][20][21], most of which were placed on infinitely rigid supports.…”

Vibration and Instability of Rotating Composite Thin-Walled Shafts with Internal Damping

“…Therefore, accurate prediction of effects of internal damping in composite material rotors is essential. So far, there have been less work related to the stability analysis, particularly effects of internal damping on the stability of a rotating composite shaft [4,[11][12][13][14]. Singh and Gupta [4,11] introduced discrete viscous damping coefficients to account for effect of internal damping.…”

“…Singh and Gupta [4,11] introduced discrete viscous damping coefficients to account for effect of internal damping. In a similar approach, dynamic instability analysis of composite shaft has been performed by Montagnier and Hochard [13], Mazzei and Scott [12], Kim et al [14]. In above cases, internal damping terms were included simply in equations of motion of rotating shaft, no internal damping modeling has been described.…”