The accurate modelling of damping is essential to capture the dynamic behaviour of a MEMS device. Our interest lies in squeeze-film damping which models the behaviour of a fluid in small gaps between a fixed surface and a structure moving perpendicular to this surface (Fig.1). The lateral dimensions of the surfaces are large compared to the gap and the system is considered isothermal. Squeeze f...

A new fail-safe, variable stiffness, and variable damping isolator (VSDI) device is designed, developed and tested utilizing magneto-rheological elastomers (MREs). This system provides a simultaneous controllable stiffness and damping. The performance of the VSDI is investigated experimentally under dynamic shear loads. The results demonstrate that this VSDI is capable of increase of stiffness ...

The modeling of damping is very complex and still considered somewhat an unknown or grey area. Recently, model updating methods has been used to update the damping matrix based on measured dynamic test data to accurately represent energy dissipation mechanism in dynamic systems. Most of the finite element updating methods considers that the dynamic systems are viscous and proportional. In this ...

This study presents a study of the application of a Unified Power Flow Controller (UPFC) to control power transmission, generator terminals voltage and better damping of Low Frequency Oscillation (LFO) in Single-Machine Infinite-Bus (SMIB) power system. The UPFC integrates properties of both shunt and series compensations and can effectively alter power system parameters in a way that increases...

Materials combining high stiffness and mechanical energy dissipation are needed in automotive, aviation, construction, and other technologies where structural elements are exposed to dynamic loads. In this paper we demonstrate that a judicious combination of carbon nanotube engineered trusses held in a dissipative polymer can lead to a composite material that simultaneously exhibits both high s...

Damping properties of the inherent and intrinsic internal friction peaks (IFPT + IFI) of Cu-xZn-11Al (x = 7.0, 7.5, 8.0, 8.5, and 9.0 wt. %) shape memory alloys (SMAs) were investigated by using dynamic mechanical analysis. The Cu-7.5Zn-11Al, Cu-8.0Zn-11Al, and Cu-8.5Zn-11Al SMAs with (IFPT + IFI)β3(L21)→γ′ 3(2H) peaks exhibit higher damping capacity than the Cu-7.0Zn-11Al SMA with a (IFPT + IF...

Yaw damper represents a major source of excitation for flexural vibration of the railway carbody. In order to reduce transmissibility of such undesired excitation, yaw damper should allow for large force transmission at low working frequencies, but should behave as vibration isolator at high working frequencies. Unfortunately, the yaw oil damper (OD), which is nowadays in service, has poor intr...

Rolling bearing noise has become an aspect of increasing importance for the performance of rotating machinery, like electric motors and gearboxes. Generally, two aspects are important with regard to bearing noise, i.e. the transmission characteristics and the vibration generation characteristics. A potential source of vibrations are for example manufacturing imperfections of the di erent bearin...