The rotordynamic and leaking characteristics of two types of gas damper seals, honeycomb seal and pocket damper seal, were experimentally evaluated on a rotating test rig. The effect of supply pressure, preswirl, and seal eccentricity on seal dynamic performance was investigated in the tests. The pressurized working gas flowed through the seal and exhausted to atmospheric conditions. The maximu...

Semi-active control systems are becoming more popular because they offer both the reliability of passive systems and the versatility of active control systems without imposing heavy power demands. In particular, it has been found that magnetorheological (MR) fluids can be designed to be very effective vibration control actuators, which use MR fluids to produce controllable damping force. The ob...

We demonstrate that graphitic coatings, which consist of multilayer disordered graphene sheets, can be used for the thermal protection of delicate metal nanostructures. We studied cobalt slanted nanopillars grown by glancing angle deposition that were shown to melt at temperatures much lower than the melting point of bulk cobalt. After graphitic coatings were conformally grown over the surfaces...

A non-linear model of an adjustable automotive damper is developed, which includes the compressibility of the ̄uid, trapped gas and expansion of the cylinder. The parameters for the model are selected by ®tting the model to experimentally obtained data from the damper. The model is shown to give an excellent representation of the damper under investigation. The performance of the damper model i...

the present article seek to investigate the function of elliptical steel damper function in steel frames seismic resisting. the elliptical damper is a kind of earthquake energy dissipater in structure which acts based on the steel yielding feature. thus, this damper in frame lateral displacement mechanism is expected to have a satisfying hysteretic behavior in terms of energy absorption is on a...

additional dampers are employed in order to decrease the dynamic response of structure against the earthquake and wind loading recently. in this study, two types of systems related to waste of inactive energy, i.e. frictional damper which is categorized in dampers dependent on movement and viscoelastic damper which is categorized in dampers dependent on velocity, in making steel structures resi...

In recent years, it is considerably attempted to develop the concept of energy dissipation as an applicable technology to overcome the energy released by earthquakes. The passive control systems such as metallic dampers have been widely considered. The dampers are basically used to mitigate the structural responses and reduce the damages in main structural elements by energy dissipation. ...

Title of Dissertation: DEVELOPMENT OF MAGNETORHEOLOGICAL FLUID ELASTOMERIC DAMPERS FOR HELICOPTER STABILITY AUGMENTATION Wei Hu, Doctor of Philosophy, 2005 Dissertation directed by: Professor Norman M. Wereley Department of Aerospace Engineering Conventional lag dampers use passive materials, such as elastomers, to dissipate energy and provide stiffness, but their damping and stiffness levels d...