We discuss the use of homogenization techniques to derive approximate models with simple geometry for physical models of grids and trusses which have a complex geometry that gives rise to computational diiculties. Our presentation is in the context of inverse or parameter estimation problems for composite material structures with unknown characteristics such as stiiness and internal damping. We...

Some of the dynamic properties of violin bows have been studied. The normal modes of the bow stick and assembled bow, respectively, have been explored by modal analysis. Modefiequencies and damping ratios have been compared for a set of bows which had ratings rangzng fiom poor to excellent, assigned to them by professional players, and an attempt has been made to connect the modal properties wi...

Accurate evaluation of damping ratios involving soilstructure interaction (SSI) effects is the prerequisite for seismic design of in-situ buildings. This study proposes a combined approach to identify damping ratios of SSI systems based on ambient excitation technique. The proposed approach is illustrated with main test process, sampling principle and algorithm steps through an engineering exam...

The damping capacity and mechanical properties of Mg-6Al-1Zn alloy after heat treatment were investigated. The damping characteristics of un-heat-treated, solution treated, and aged Mg-6Al-1Zn specimens were determined by measuring the damping ratio and the logarithmic decrement of free vibrations of a bending beam clamped at one side. The microstructural evaluations confirmed that the β-Mg17Al...

Modal active control enables modifications of the damping and the frequencies of the different resonances of a system. A self-sustained oscillating wind instrument is modelled as a disturbance coupled to a resonator through a non-linear coupling. The aim of this study is to present simulations of modal active control applied to a modeled simplified self-sustained oscillating wind instrument (e....

In this paper recursive subspace identification algorithms are applied to track the modal parameters of airplanes on-line during test flights. The ability to track changes in the damping ratios and the influence of the forgetting factor are studied through simulations.

We discuss the use of homogenization techniques to derive approximate models with simple geometry for physical models of grids and trusses which have a complex geometry that gives rise to computational diiculties. Our presentation is in the context of inverse or parameter estimation problems for composite material structures with unknown characteristics such as stiiness and internal damping. We...

This paper provides an overview of methods to detect, locate, and characterize damage in structural and mechanical systems by examining changes in measured vibration response. Research in vibration-based damage identification has been rapidly expanding over the last few years. The basic idea behind this technology is that modal parameters (notably frequencies, mode shapes, and modal damping) ar...