... characterization that must be considered for reliable operation. Finally, it examines in detail the geometrical configurations, load-bearing capacity, dynamic behavior, and stability connected with stiffness and damping. Email: p_samanta@cmeri.res.in Emails: hirani@mech.iitd.ac.in ; director@cmeri.res.in...

... motion and then no damping exists. Under this condition, the contact body is only supported by the elastic restoring force. By analyzing the changes of steady state mutual approach with load in Fig. 5 , the variations of stiffness with load can be analyzed qualitatively. Figure 5 shows...

... metal bearings with relatively large permeability could achieve large values of dynamic stiffness and damping coefficients using a low permeability, surface-restricted layer. 20 01 2010 26 09 2010 03 12 2010 03 12 2010 damping elastic constants graphite machine bearings...

... coordinate systems are built up in matrix form. A fast algorithm using the Newton–Raphson method for calculating the equilibrium position of journal and pads is proposed. The eight reduced stiffness and damping coefficients can be obtained assuming that the journal and all pads are subject to harmonic...

... with hysteresis damping via the dynamic analysis. In the second procedure, a contact force model with hysteresis damping is used to estimate the joint forces. In the latter case, however, the contact pressure is estimated using a finite element method (FEM). A comparison in performance of the two models...

...Jianhua Li; Junguo Xu; Yuki Shimizu; Masayuki Honchi; Kyosuke Ono; Yukio Kato Perturbation and modal-analysis methods were employed to systematically study a damped slider’s dynamic characteristics, including an air-bearing slider’s stiffness, damping coefficient, frequency response to translation...

...Adolfo Delgado; Luis San Andrés Squeeze film dampers (SFDs) aid to reduce excessive vibration levels due to rotor imbalance and to raise stability thresholds in rotor-bearing systems. SFDs commonly include end seals to increase their damping capability with a lesser lubricant flow. Seals also aid...

... planes depend on the actual seal or SFD configuration. Integration of the resulting first-order pressure fields on the journal surface yields the force coefficients (stiffness, damping, and inertia). Current model predictions are in excellent agreement with published test force coefficients for a grooved...

... as compared with Newtonian lubricant but the bearing lubricated with lubricant having higher micropolar effect is predominantly affected by the wear vis a vis static characteristics parameters as compared with Newtonian lubricant for both loading arrangements. However, in the case of stiffness and damping...

... rarefactions with the Poiseuille and Couette flow rate correctors. The gas film in the rotor-bearing system is modeled as stiffness and damping elements with coefficients dependent on the exciting frequency. The dynamic coefficients are then obtained by solving the linearized MMGL equations. The equations...

...Tae Ho Kim; Anthony W. Breedlove; Luis San Andrés Oil-free turbomachinery relies on gas bearing supports for reduced power losses and enhanced rotordynamic stability. Gas foil bearings (GFBs) with bump-strip compliant layers can sustain large loads, both static and dynamic, and provide damping...

... by an infinite incompressible fluid and subjected to an external pressure. This equation is obtained from the momentum equation and it takes into account the ensemble of the phenomena related to the dynamics of the bubbles (surface tension, damping, and inertia). All the terms in the RP equation will be taken...

... coefficients increase with frequency, whereas equivalent direct damping coefficients dramatically reduce. For higher perturbation frequency, the dynamic coefficients are nearly independent of the frequency. Moreover, the equivalent dynamic coefficients of four-pad tilting-pad gas bearing obtained by the method...

...G. Belforte; F. Colombo; T. Raparelli; V. Viktorov A test bench for rotors supported by air bearings floating on O-rings is designed in order to study the whirl phenomenon and characterize the stability threshold with damping elements mounted on bearings. The work includes a description of the test...

... models are typically used. A critical element of these models is the contact stiffness and damping arising from the interfacial interaction between the slider and the disk. In this paper, we review different models for predicting contact stiffness based on roughness and layered media and then we report...

... are mechanically complicated, and therefore also sensitive to impacts. The most frequently examined characteristics of retainer bearings are stiffness, damping, and friction coefficients between the rotor and bearing. The influence of those coefficients is widely known as reviewed by Zeng ( 5 ) and Ishii...

... have been proposed to solve this problem such as the pad assembly method and the small perturbation method. A numerical method by combining the partial derivative method with the equivalent coefficient method is presented in this paper to evaluate the dynamic stiffness and damping coefficients of self...

...Yasunaga Mitsuya; Yasuji Ohshima; Hedong Zhang; Kei Aoyama; Toshiyuki Kawai; Kenji Fukuzawa Spring constants and damping coefficients of a thin lubricant bridge of a perfluoropolyether (PFPE) lubricant intervening between a diamond probe tip and a diamond-like carbon (DLC) surface of a magnetic...

... by using periodicity boundary conditions. The stiffness and the damping of the annular seal were calculated by using the modified bulk-flow model and results were compared with the experimental data from Childs and Fayolle. The use of the present model shows a net improvement of the predictions...

... an excellent agreement with an analytical model developed for the spring bumps. Load capacity, structural stiffness, and equivalent viscous damping (and structural loss factor) were measured to demonstrate the feasibility of the new foil bearing. Orbit and coast-down simulations using the calculated stiffness...