ДОСЛІДЖЕННЯ ВПЛИВУ ПІДВИЩЕНОЇ ТЕМПЕРАТУРИ НА ДИСИПАТИВНІ ВЛАСТИВОСТІ ОДНОСПРЯМОВАНОГО ВУГЛЕПЛАСТИКУ

Abstract

An experimental method for determination of composite materials dissipative properties, the main characteristic of which is the minimization of external energy losses and ensuring uniform distribution of deformations along the specimen working part under the pure bending condition has been developed. The scheme of the modernized experimental setup is presented. Its mechanical system represents a closed circuit in which the energy in material specimen under flexural vibrations is dissipated. Automated testing and registration of vibration characteristics were carried out by the method of attenuating vibrations at different temperatures. Based on the results for a set of experimental studies on the determination of the dissipative properties of unidirectional CFRP specimens under the pure bending conditions, the dependencies of the logarithmic decrement of vibrations on the relativedeformation in the range (2...12)∙10–4for temperatures from 300 K to 423 K was established.To analyze the effect of temperature on the dissipative properties of the composite, a parameter is proposed that is determined by the increment of the logarithmic decrement of vibrations (LDV) before deformation. It is shown that it is a more informative indicator of the structural integrity of carbon fiber samples, even with a relatively small violation of it due to heating and simultaneous cyclic deformation, compared to the relative growth of the LDV and the drop in the vibration frequency.The obtained experimental data and the presented method of investigation the dissipative properties of materials can be used as a directory data in the design of new models of equipment and in the development of mathematical models of composite structural elements operating under dynamic loads and elevated temperatures.