Papers by Keyword: Mechanical Damping

Abstract: Fibre-reinforced ceramic composite materials offer excellent thermal, mechanical and chemical properties. Due to their intrinsic fibre structure and porosity, they offer a great damage tolerance. Therefore, they provide superb attenuation characteristics, as do polymer composites. The current compound systems consisting of ceramic components feature a rather low capacity for energy absorption in relation to their weight; this is a fact in dire need of a fundamental change. In regards to the development of new hybrid ceramic/polymer material compounds basic research of the material design and binding behaviour of the different components is necessary. The advantage of this development allows for a selective implementation of positive characteristics of one component in an integrated compound-system. This opens up completely new possible are-as of application, such as wear and tear resistant and chemically inert, energy absorbing elements for the construction of reactors or areas of medical technology. During the investigation, a few selected fibre-reinforced ceramic composite materials with a specific porosity were produced, while adjusting the amount of resin/hardening agent used, as well as modifying other parameters. This was followed by tests regarding the wetting with a polyurethane component. The characterisation and analysis of the hybrid compounds on a microscopic scale is achieved by means of optical microscopic examinations. The characterisation of the mechanical attenuation characteristics on the other hand is realised by means of DM(T)A. The flexural strength is determined by utilising a “three-point-bending test”.

Abstract: A new algorithm OMI (Optimization in Multiple Intervals) for the computation of the logarithmic decrement from exponentially damped harmonic oscillations is described. This method is shown to be effective and computationally compact for high damping materials. A comparison between the OMI algorithm and the four classical methods usually used in the computation of the logarithmic decrement is reported. The OMI algorithm yields high precision in the computation of the logarithmic decrement and the smallest dispersion of experimental points on the plots of mechanical loss spectra. The effect of the acquisition parameters and the experimental conditions on the results of computations of the logarithmic decrement and the relative error is discussed.

Abstract: A list of monographs on internal friction, anelasticity, ultrasonic attenuation, relaxation phenomena in solids, and mechanical spectroscopy published in Soviet Union, Russia, and Ukraine is provided. A complete list of proceedings from international and Russian conferences is also given. This work is a valuable supplement to the Mechanical Spectroscopy - Suggested Reading Series.