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Registration Number

0220U101760, 0117U000396 , R & D reports

Title

The development of methods and algorithmic-software of the analysis of low-energy diagnostic signals and parameters of the thermomechanical behaviour of construction elements

Head

Nazarchuk Zinoviy T., Доктор фізико-математичних наук

Registration Date

20-02-2020

Organization

State western scientific center NAS of Ukraine and MES of Ukraine

Description

 The peculiarities of AE signals generation during the fracture of structural steels are investigated and the quantitative indicators of change in the spectral parameters of AE signals for different types of fracture are determined. A method of determination of nonstationary thermal and thermostressed states of radially inhomogeneous hollow cylindrical bodies in the absence of information on temperature load on one of the boundary surfaces is proposed. It is stable to small errors of the input data. A software was developed to determine the stress-strain state of structural elements from inhomogeneous heat-sensitive materials. It is based on the proposed mathematical model for the description of deformation processes in solids under complex loading using the finite element method. The breadboard of the optical-digital system with the scheme for recording of focused-image digital holograms and speckle patterns has been built. The experimental setup has been created for reconstructing surface displacement and deformation fields of sheet composite materials and studying the processes of composites crushing near the round openings. Series of focused-image digital holograms and Fresnel digital holograms and speckle patterns of the sheet multilayer composite surface area containing round opening are obtained experimentally. The reconstructed three-dimensional surface displacements have indicated initiation and further development of the composite crushing near the round opening. Mathematical model to determine the spectrum of transverse vibrations (SH-type waves) in the junction of the plate with half-space in the presence of internal and interphase defects like the cracks is proposed. The complex resonant frequencies that allow to select the optimal frequency of the probing field are determined mathematically correct for diagnosing the layers depending on the geometric parameters of the structure and its physical and mechanical characteristics.

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