In this study, control performance of a smart base isolation system consisting of a friction pendulum system (FPS) and a magnetorheological (MR) damper has been investigated. A fuzzy logic controller (FLC) is used to modulate the MR damper so as to minimize structural acceleration while maintaining acceptable base displacement levels. To this end, a multi-objective optimization scheme is used t...

Measurements of the Zener relaxation in single crystals of Cu-18at.%Au and Cu3Au are presented. In the laat.% alloy only one internal friction peak is observed at low frequencies (of the order of 1 Hz). This peak is only slightly wider than a Debye's peak. An additional hump appears at intermediate frequencies (of the order of 60 Hz). The Zener peak in the Cu3Au alloy is accompanied by an addit...

Internal friction and frequency measurements as a function of temperature have been carried out in Nb and Nb-Zr policrystalline samples, using a torsion pendulum in the temperature range between 300K and 700K, the heating rate was lWmin and the pressure was kept better than 5x10~~ mbar. Metals with bcc lattice containing solute atoms dissolved interstitially often show anelastic behaviour due t...

This paper describes a novel method for the modeling of intermittent contact in multi-rigid-body problems. We use a complementarity based time-stepping scheme in Featherstone’s Divide and Conquer framework to efficiently model the unilateral and bilateral constraints in the system. The time-stepping scheme relies on impulse-based equations and does not require explicit collision detection. A se...

Hypernymy is the key relation that serves to form the ontology of the noun and verb concepts in WordNet and provides a common way of making induction along the hypernymy tree for the NLP researchers. Howerver, we find 2 kinds of abnormal hypernymy in WordNet 2.0, the cases of ring and isolator for short, which can largely harass the reasoning and eventually lead to errors.

The behavior of a spatial double pendulum (SDP), comprising two pendulums that swing in different planes, was investigated. Movement equations (i.e., mathematical model) were derived for this SDP, and oscillations of the system were computed and compared with experimental results. Matlab computer programs were used for solving the nonlinear differential equations by the Runge-Kutta method. Four...

Experimental and analytical studies of a seismically isolated five-story model structure are conducted to understand the behavior of a novel uplift-prevention Friction Pendulum isolator. Shake table testing on the earthquake simulator at the University at Buffalo involves a number of simulated ground motions with a variety of frequency content and amplitude. A comprehensive analytical model is ...

Some results of the influence of y radiation on the mechanical properties of PoIymethylmethacrylate are presented. Doses of 0, 50, 100, 150 and 200 kGy were employed. The internal friction (loss tangent) and storage shear modulus were measured at temperatures between 173 K and 300 K using a damped torsion pendulum. Compressive tests were made at room temperature with strain rates between 1 . 4 ...