Nonlinear Behavior of an Elastomeric Lag Damper Undergoing Dual-Frequency Motion and its Effect on Rotor Dynamics

Anelastic Behavior in Filled Elastomers Under Harmonic Loading Using Distributed Rate-Dependent Elasto-Slide Elements

“…Under such a circumstance, the potential loss of damping at the lower frequency due to limitation of stroke is well known [5], so it is important to predict the response of the elastomer under dual frequency excitation. Experimental dual frequency force-displacement data of the elastomer specimen 1 were used to evaluate the adaptability of the model under complex loading conditions.…”

“…Felker et al. [5] further developed a nonlinear complex modulus model based on a single Kelvin chain, in which the spring force was a nonlinear function of the displacement, and the damping force was a nonlinear function of displacement and velocity. This model was used to describe the amplitude dependent moduli and to study dual frequency damper motions.…”

<title>Nonlinear modeling and performance prediction of electrorheological fluid dampers</title>

“…In order to compare the damping performance of a controllable fluid damper with that of a conventional viscous dashpot damper, an equivalent damping coefficient can be determined for the former by equating the energies dissipated in the two cases. Thus Ceqv irwX (2) where w is the excitation frequency and X0 is the displacement amplitude. The equivalent damping coefficients for different sets of data are plotted in Fig.…”

“…However, elastomers are highly nonlinear materials whose properties are dependent on both frequency and temperature. Their nonlinear dual frequency behavior has been shown to reduce damping and thus cause limit cycle oscillations at low amplitudes [2]. In order to circumvent the problems associated with elastomers, Fluidlastic dampers have been proposed whose stiffness remains relatively constant with amplitude [3, 4J.…”

<title>Nonlinear viscoelastic damper model: constitutive equation and solution scheme</title>

“…Since nonlinear system response would contain higher harmonics, we assume it to be x = : {x cos nt + x9 sin nct} (5) The expressions for damper force D = D0 sin , assumed damper displacement (5), and their derivatives, are introduced into the nonlinear constitutive equation (3). Since we are only interested in the coefficients x1 and x1, (hereafter referred to as x and x5), (3) is multiplied by cos t and sin t respectively, and integrated from t=O to 2ir/fI to yield…”