A study on the evaluating equivalent damping and response modification factors of frames equipped by Pall Friction Dampers is presented. To do so, buildings with various stories were considered. Nonlinear and linear dynamic time history analysis has been performed to evaluate equivalent damping for Pall Friction Dampers. Ground motions with various frequency characteristics scaled with Iranian ...

A dynamic system with structural damping described by partial differential equations is investigated. The system is first converted to an abstract evolution equation in an appropriate Hilbert space, and the spectral and semigroup properties of the system operator are discussed. Finally, the well-posedness and the asymptotical stability of the system are obtained by means of a semigroup of linea...

This paper proposes a novel method to test the dynamic damping characteristics of valve. The testing system employs the vertical movement pattern, and has a suspension support structure. Force sensors are installed to measure the dynamic friction of the working valve directly. Making use of LuGre friction model and both adaptive genetic algorithm and chaos particle swarm optimization algorithm,...

when power systems are expanded and connected together with weak tie lines, the low-frequency oscillations are increased and the stability margin of the power system decreases. therefore, when designing the transmission system to be used, it is necessary to maintain the dynamic stability of the power system, and to make sure to have the most possible stability margin. sssc is a facts device con...

The strapdown fiber optic gyrocompass (strapdown FOGC) system for ships primarily works on external horizontal damping and undamping statuses. When there are large sea condition changes, the system will switch frequently between the external horizontal damping status and the undamping status. This means that the system is always in an adjustment status and influences the dynamic accuracy of the...

The problem of characterizing response variability and assessing reliability of vibrating skeletal structures made up of randomly inhomogeneous, curved/straight Timoshenko beams is considered. The excitation is taken to be random in nature. A frequency-domain stochastic "nite element method is developed in terms of dynamic sti!ness coe$cients of the constituent stochastic beam elements. The dis...

A novel class of narrow band filters is presented that offers great rejection of out of band noise and a flat top at the peak. The filter is unconventional, as the output of such a filter is a series of spikes, like the action potential in the auditory nerve. The product of its time and frequency window is less than unity even using 100% output cutoff points. A bank of such filters has been use...

Damping in Dynamic Force Microscopy: The Role of Functionalized Groups. As a relatively new scanning probe technique, Dynamic Force Microscopy [1] has proved to be a powerful tool, allowing for imaging the topography of a sample surface with true atomic resolution. Besides topographic imaging, the simultaneously recorded damping signal is related to non-conservative interaction between tip and ...

The viscoelastic properties of three commercially available resin-based composites (FiltekTM P60, FiltekTM Supreme, and FiltekTM Z250; 3M ESPE, Bracknell, UK) were measured to determine the effect of beverages on their storage moduli and damping ratios. Rectangular samples of the three hybrid composites were immersed in three beverages at 37 °C for 1, 7, 30, and 60 days. At each time interval, ...