... of aerodynamic damping is significant with respect to limit the forced response since structural damping ratios of integrally bladed rotors typically take extremely low values. Hence, detailed knowledge of respective damping ratios would be desirable while developing a robust rotor design. For this, far-reaching...

... proposed solutions to this, some passive and some active. With the advent of additive manufacturing (AM), new damping techniques can now be incorporated directly into the design and manufacture process to suppress the vibrations that cause HCF. Recent work has been investigating new ways of using AM...

...Christos I. Papadopoulos; Pantelis G. Nikolakopoulos; Lambros Kaiktsis In the present paper, a study of stiffness and damping in sector-pad micro thrust bearings with artificial surface texturing is presented, based on computational fluid dynamics (CFD) simulations. The bearing pads are modeled...

... damping coefficients. Direct stiffness coefficients were larger for the 60% offset bearing at light unit loads. At high loads, the 50% offset configuration had a larger stiffness in the loaded direction, while the unloaded direct stiffness was approximately the same for both pivot offsets. Cross-coupled...

... damping and tolerance to minor shaft misalignment and external shocks. In addition, the low viscosity of air or gas allows very low power consumption even at high speeds. A turbine simulator mimicking 50 kW power generation gas turbine was designed. The turbine simulator can generate the same...

...Jacob Laborenz; Malte Krack; Lars Panning; Jörg Wallaschek; Markus Denk; Pierre-Alain Masserey In the dynamics of turbomachinery, the mechanical damping of the blading has been the focus of research for the last decades to improve the dynamic performance in terms of high cycle fatigue issues...

...C. W. Schwingshackl; E. P. Petrov; D. J. Ewins The design of high cycle fatigue resistant bladed disks requires the ability to predict the expected damping of the structure in order to evaluate the dynamic behavior and ensure structural integrity. Highly sophisticated software codes are available...

...Loïc Salles; Laurent Blanc; Fabrice Thouverez; Alexander M. Gouskov; Pierrick Jean Contact interfaces with dry friction are frequently used in turbomachinery. Dry friction damping produced by the sliding surfaces of these interfaces reduces the amplitude of bladed-disk vibration. The relative...

...Yong-Bok Lee; Chang Ho Kim; Tae Ho Kim; Tae Young Kim Metal mesh materials have been used successfully in vibration isolators and bearing dampers due to their superior friction or hysteresis damping mechanism. These materials are formed to metal mesh (or wire mesh) structures in ring-shape...

...Kwen Hsu; Daniel Hoyniak The blade geometric variations are usually ignored in the prediction of bladed disk aerodynamic damping values. This situation is the result of the high computational cost associated with the full-annulus unsteady flow CFD models required to account for these blade...

... and common materials. The bearing incorporates a copper mesh ring, 20% in compactness, and offering large material damping beneath a 0.127 mm thick preformed top foil. Prior experimentations (published papers) provide the bearing structure force coefficients and the break away torque for bearing lift off...

..., gas lubricated bearings generate very little damping from the gas itself. Therefore, successful bearing designs such as foil bearings utilize damping features on the bearing to improve the damping generated. Similar to oil bearings, gas bearing designers strive to develop gas bearings with good...

... in this paper, and the high sensitivity of high-cycle-fatigue-related fatigue life to the level of vibration response levels is presented. Computer simulations are run to study the distribution of the amplification factor in three situations, namely, (i) bladed disks with damping mistuning, (ii) EO excitation...

... of new combustion concepts concerning higher efficiency and lower emissions. While the successful application of such a damping concept has been shown, it is still not possible to accurately predict the damping performance of a given configuration. This paper provides a comprehensive database of high...

.... At low unit loads, stiffness orthotropy defined as K y y / K x x is the same for LOP and LBP, progressively increasing with increasing unit loads. At the highest unit load, K y y / K x x = 2.1 for LOP and 1.7 for LBP. Measured direct damping coefficients C x x and C y y were insensitive to changes...

...Pham Minh Hai; Philip Bonello The integration of squeeze-film dampers (SFDs) in aero-engine assemblies is a highly cost-effective means of introducing damping in an otherwise lightly damped structure. However, their deployment requires careful unbalance response calculations that take due account...

... and the robustness of the optimum mistuning patterns has been demonstrated. The combined effect of the aerodynamic and structural damping on the response reduction is assessed. It is shown that the new phenomenon is of major practical significance and has to be taken into account in analysis of the forced response...

... also calculated for various operating conditions. The direct stiffness increases with supply pressure but the direct damping decreases with supply pressure. In addition, typical hardening effect of gas film accompanying increase of stiffness and decrease of damping was predicted in high frequency...

... structural parameters, stiffness and damping, as a function of excitation frequency and amplitude of motion. The identified FB stiffness and viscous damping coefficients increase with shaft temperature due to an increase in the FB assembly interference or preload. The bearing material structural loss factor...

...Albert Kammerer; Reza S. Abhari The vibratory response amplitude of a blade under forced response conditions depends primarily on the aerodynamic excitation amplitude, on damping, and on the effects of mistuning. The work presented here targets to identify the individual contribution...