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[en] To limit the seism effects, structures may be base isolated. A sliding system located between the structure and the support allows differential motion between them. The aim of this paper is the presentation of the method to calculate the response of the structure when the structure is represented by its eigenmodes, and the sliding phenomenon by the Coulomb friction model. Finally, an application to a simple structure shows the influence on the response of the main parameters (friction coefficient, stiffness,...)

[en] The principle of internal friction is briefly introduced. With some specific examples the possible applications of internal friction in the investigation of condensed matter physics and materials sciences are reviewed. It is pointed out that the main objectives of this research field are to develop new measurement methods and internal friction technology, discover new internal friction spectra, and establish a new internal friction model and theory. (authors)

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[en] The average force of kinetic friction that occurs when layered compounds (which are commonly used as solid lubricants) are sheared in steady state is calculated for a model for such substances, assuming that the dissipation is caused by the excitation of lattice vibrations in one surface by the other. Because at slow speeds shearing is believed to be due to dislocation motion, a model for slow-speed shearing due to dislocation motion has been formulated. The force of friction is found to be inversely proportional to the sliding velocity for velocity small compared to the velocity of sound in the material and proportional to the area of the slipping surfaces. The dissipative stress at a sliding speed of 1 cm/s is calculated to be 10⁸ dyn/cm². The dissipative stress, calculated for slippage of two incommensurate surfaces, is found to be only 10^-4 dyn/cm², however, which opens up the question of whether lubrication is caused by slippage of the lubricant relative to the sliding surfaces rather than by shearing of the solid lubricant crystal

[en] An inverted torsion pendulum is automatized by means of Tectanel electronic system. Internal friction and the period of vibration are measured fully automatically as a function of temperature and the data obtained are analysed with a computer. (Author)

[en] The proceedings contain 45 papers on a wide range of subjects including flow generated instabilities in fluid flow machines, cracked shaft detection, case histories of instability phenomena in compressors, turbines, and pumps, vibration control in turbomachinery (including antiswirl techniques), and the simulation and estimation of destabilizing forces in rotating machines. The symposium was held to serve as an update on the understanding and control of rotating machinery instability problems