International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This paper presents the results of studies on the thermophysical and sound-insulating properties of new composite materials intended for interior and exterior plasters in construction. The materials were developed on the basis of foam glass granules and thermally treated rice husks using a specialized methodology. The guarded hot plate method was used to investigate the thermal insulation properties of the composite plasters. Tests for determining the acoustic insulation characteristics were carried out under laboratory conditions using the two-chamber method. The results show that the newly developed composite plasters exhibit better thermal and acoustic insulation properties than the standard plaster compositions traditionally used in construction.

This paper presents experimental investigations using a vibration method by impulse excitation of free flexural oscillations of composite beams. The purpose of the study is to establish the sensitivity of the method and technique used for defect detection and localization. To realize the objective, rectangular groove type defects were simulated at different distances and depths. The influence of the location and depth of the artificial cracks on the dynamic properties of the beams was investigated. The resonance frequencies were determined by frequency analysis. A decrease in the resonant frequencies of the flexural oscillations is observed. The experiments conducted show a change in the dynamic characteristics of the beam depending on the dimensions and location of the defects.

This paper presents the results of an investigation conducted on samples of high-quality heat-treated carbon steel using the magnetic noise method. The objective of the work was to find the proper informative parameters for identifying the obtained s tructures with different hardness. To this end, samples were prepared using quenching and tempering heat treatment at different temperatures , from 150°C to 500°C. After microstructural analysis and hardness measurements, the samples were investigated using the magnetic noise method. The signals were visualized and analyzed using a digital oscilloscope and the Multi Instrument 3.8 software program. The RMS informative parameters and the registration time of the magnetic noise signals were used to identify the obtained microstructures with different characteristics and hardness.

The article presents a study of the sound and thermal insulation properties of ceramic plates with cavities, designed for beehives. The plates are obtained by the “casting” method from a water-dispersed colloidal system based on a patent-protected quartz glass-ceramic. They are composed of amorphous SiO2, mullite and cristobalite. To measure the thermal conductivity, a thermal chamber is constructed with a heater installed in it. Given that the heat flow passing through the three-layer ceramic plate for beehives is constant, the temperature difference between the two opposite sides of the plate at steady state (at constant heat flow) is measured and the thermal conductivity is calculated. A two-chamber method is used to determine the sound insulation capacity of the ceramic plates for beehives. The sound pressure of the sound waves – the incident one and of the wave which has passed through the sample –is measured in the frequency range from 100 to 3150 Hz

In summary form, some trends in the production and application of foamed silicate materials obtained from recycled waste materials are presented. The existing possibilities for the use of different fractions of foam glass granules for the preparation of various products (lightweight concrete, colored decorative panels, etc.) are considered. Experimental samples are prepared in which the average value of the thermal conductivity coefficient =0.24±0.13 W/m. K was established. The main technological factors determining the operational characteristics of the material and the existing potential prospects for their optimization are analyzed.

The coefficients of sound absorption and reflection in the frequency range up to 2 kHz, here respectively 0.2 and 08, as well as the coefficient of thermal conductivity, here below 0.027, of a new porous composite material were studied. The material was obtained from ground household glass waste and rice grains husks burned at temperature from 4000C to 7000C. The results show that the material has good sound reflectivity and low thermal conductivity, which makes it suitable for the manufacture of modules for thermal and sound insulation.