Short Description

The problem of reducing the levels of acoustic impact on the environment or indoor is currently one of the main problems of safe human life and the trouble-free functioning of complex technical objects. Creating less noisy technical devices and equipment could not solve the problem, since at the same time there is a significant increase in the produced units. In some areas, for example, aviation and the air force, the urgency of the problem is steadily increasing, as the intensity and timing of uninterrupted flights and, accordingly, the continuous acoustic loading of aircraft crews and airport staff and maintenance personnel are increasing significantly. The European Union’s Green Book asserts that more than 20% of the world's population is exposed to temporary acoustic impacts, and 170 million European citizens live in areas subject to noise attacks during the daytime. On the other hand, the protection of the acoustic component of the information involves the development of passive methods and means of maximally attenuating the acoustic energy of sound sources. The current thorough analysis of the technical aspects of the noise pollution and insulation problems shows that the construction materials will play a key role in reducing acoustic noise levels. 
The aim of the project is to identify the appropriate ingredients and to develop technologies for producing sound-insulating and sound-absorbing composite materials to reduce the energy of wide-range acoustic radiation, including short-term impulsive influences, which make it possible to meet the requirements of noise ecology and acoustic safety of the human environment and nature. 
The main tasks of the project are i) development of numerical methods for the structure modelling of noise-reducing composite materials with improved sound-insulating and sound-absorbing properties in a wide frequency range; ii) identifying of the mechanisms and examining the patterns of sound pressure reduction in viscoelastic media containing complex nanoscale fillers; iii) development of methods for material’s structure modification combined with variation of the technological modes to matching the input impedance of the condensed absorber with the wave impedance of the environment, this way minimizing the reflected waves; iv) experimental optimization of the compounding technology, the structure and the dimension of the components according to the criterion of best attenuation of the sound energy; v) development of a new technology for environmentally friendly multifunctional acoustic composite materials. 
Enhancement of the insulating and absorption capacity and ability of the developed composites will be achieved by using as a matrix viscoelastic polymer modified with nanosized carbon and silicate particles. In order to guarantee the environmental protection of the production, operation and disposal of the proposed acoustic composites, the technology to be developed within the project envisages the use of natural fibers, which will allow the production of partially biodegradable materials. In addition, it is foreseen to ensure the multifunctionality of the composites by modifying the polymer matrix with fine particles of amorphous metal alloys and ingredients with chirality properties (chiral components), which will give the developed acoustic materials the properties of microwave absorbers and thus be able to be used for objects with low radar visibility. 
Characterization of the composite material properties will be optimized through utilization of the Machine Learning (ML). Data for the ML optimization will be gathered from the simulation models, laboratory measurements of the material properties, as well as from real-time data logging once material is applied in industrial environment. For the purpose of real-time data gathering, custom measurement setup based on the microphone arrays will be developed, its algorithms optimized using ML methods and appropriate database and web IT server system created. This unique database will be extremely useful for investigation of composite material properties consistency and its mechanical wear and tear, after being applied in harsh environment. 
The expected results of the project are i) a new design-experiment technique for determining the properties of sound-absorbing media; ii) a methodology for numerical modelling of the behaviour and the acoustic properties of composite materials and noise-reducing constructions; iii) new composites, allowing to reduce the noise level by 8-30 dBA in the specified sound frequency and temperature ranges, having the properties of biodegradability, thermal insulation and absorption of electromagnetic radiation. Moreover, an experimental verification of the effectiveness of composites will be performed with the assistance of potential consumers (end users). The execution of the project will provide training and raising of the professional skills level of the project members in the field of vibroacoustics