Ternopil Ivan Pul'uj National Technical University

About: Ternopil Ivan Pul'uj National Technical University is a based out in . It is known for research contribution in the topics: Deformation (engineering) & Fracture toughness. The organization has 134 authors who have published 187 publications receiving 1019 citations.

Electron correlations in narrow energy bands: ground state energy and metal-insulator transition

Abstract: The electron correlations in narrow energy bands are examined in framework of the Hubbard model. The single-particle Green function and energy spectrum are obtained in paramagnetic state at half-filling by means of new two-pole approximation. In the ground state analitical expressions for the energy gap, polar states concentration and energy of the system are found. Metal-insulator transitions in the model at change of bandwidth or temperature are investigated. The obtained results are used for interpretation of some experimental data in narrow-band materials.

Assessment of the Probability of Failure of Reactor Vessels After Warm Pre-stressing Using Monte Carlo Similations

Abstract: The probability of failure of reactor vessel with semi–elliptic crack after warm pre-stressing was assessed taken into account the scatter of mechanical properties and loading parameters by Monte–Carlo with importance sampling and first–order reliability method based on limit–state functions from FITNET procedure. The failure assessment diagrams were obtained by means of Monte–Carlo simulations for different crack depth and variable internal pressure.

Analysis and automated fatigue damage evaluation of a 17Mn1Si pipeline steel

Abstract: Digital identification and evaluation of the fatigue damage accumulation kinetics on the surface of the fatigue sensor from steel 17Mn1Si is performed using the digital image processing method. The accumulation of defects was assessed based on the analysis of the diagnostic results for individual stages of cyclic deformation. It is established that the graded nature of the fatigue crack growth is in a good agreement with the parameters of the image of the analyzed surface. Based on the gradual processing of the results obtained for the surface damage the main regularities in the development of shear and rotational processes are found. The theoretical preconditions and experimental results are presented.

On the Effects of Interacting Anisotropic Fibers on the Microbuckling in a Composite

Abstract: An analysis of microbuckling in a composite with anisotropic fibers under compression is presented. The modelling accounts for the fiber interaction, the distinct difference in the properties of the fibers and the matrix, and also for the presence of the external boundary. Results are calculated for cases of perfect fiber-matrix bonding. It is demonstrated that the critical loading parameters can depend essentially both on the fiber anisotropy and the fiber interaction. These factors must be properly accounted for in order to get acceptable estimations of the critical loads.

New black-filled epoxy coatings for repairing surface of equipment of marine ships

Abstract: The methods for ensuring long-term and safe operation of marine equipment due to comprehensive repair technologies that use epoxy oligomers and new compositions based on them are developed. The influence of temperature and UltraSonic Treatment (UST) on the rheological properties of the pure epoxy matrix and compositions based on it is explored. The compositions have different content of nanodispersed soot carbon black of brand PowCarbon 2419G (particle size of 24 ± 2 nm). It is established that when nanoparticle soot (q = 0.10…15.00 pts wt) is introduced into the composition of the epoxy matrix treated with ultrasound, the viscosity of the composition increases gradually. Based on the results obtained, temperature ranges are recommended, in which the viscosity of the studied compositions reaches optimal technological parameters for the effective impregnation of threads, tows and various fabrics, and which provide for the effective application of the composition to the working surfaces of marine equipment. Technical recommendations are given for applying the developed black-filled epoxy compositions to the working surfaces of parts, ship mechanisms and pipeline systems of marine vessels.