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.

Cyclic Linear Random Process As A Mathematical Model Of Cyclic Signals

Abstract: Abstract In this study the cyclic linear random process is defined, that combines the properties of linear random process and cyclic random process. This expands the possibility describing cyclic signals and processes within the framework of linear random processes theory and generalizes their known mathematical model as a linear periodic random process. The conditions for the kernel are given and the probabilistic characteristics of generated process of linear random process in order to be a cyclic random process. The advantages of the cyclic linear random process are presented. It can be used as the mathematical model of the cyclic stochastic signals and processes in various fields of science and technology.

Modification of structure and luminescence of ZnO nanopowder by the laser shock-wave treatment

Abstract: The paper presents the results of the ZnO nanopowder modification investigation by means of laser shock-wave treatment. The peculiar effects of such treatment were studied at the energy density rate of ∼108–109 W/cm2. The ZnO nanopowder properties were explored by using such methods as X-ray diffraction analysis (XRD), scanning electron microscopy and also by photoluminescence spectra decomposition analysis. The XRD study of ZnO nanopowder sample revealed its crystalline structure with the typical hexagonal wurtzite phase. It was also proved that laser shock-wave treatment allows to essentially changing the aggregation level of nanopowder. Additionally, the photoluminescence spectra changes of ZnO naopowders were explored both under air ambient and vacuum for the initial and laser shock-wave treated nanopowder. The decreasing intensity of green photoluminescence band and increasing intensity of the peak λ =430 nm was observed when ambient air pressure decreases. The registered changes of visible emission are referred to the modification of defect structure, especially oxygen defects. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Assessment of the Influence of Corrosive Aggressive Cargo Transportation on Vehicle Reliability

Abstract: The analytical models for calculating the performance of vehicles used to transport fertilizers have been developed. The durability of undercarriages elements is estimated with consideration of kinetic equations for determining the periods of nucleation and propagation of cracks. The formulas for determining the durability of П-shaped thin-walled sections as the sum of the periods of nucleation and subcritical growth of corrosion-fatigue cracks in metal structures of vehicles, depending on the conditions of operation, are applied as well.

Structural levels of the nucleation and growth of fatigue crack in 17Mn1Si steel pipeline after long-term service

Abstract: The majority of modern gas pipelines in Ukraine, Lithuania and Russia have been operating for more than 30–40 years. The problem of forecasting residual life-time of materials comprising such gas pipelines calls for study of their degradation kinetics as well as requires to determine its relationship with the strain-force loading parameters. The aim of the paper is to study the kinetics of fracture in order to range mechanisms of cyclic deformation of 17Mn1Si steel at nucleation and growth of a fatigue crack. Flat specimens were cut out from a fragment of 17Mn1Si steel pipe after 40 years of service. Microstructures of specimens were examined. In the paper, an attempt was made to apply the combined approach to study of deformation and fracture based on the following research parameters from nonlinear fracture mechanics: physical mesomechanics and numerical fractography.