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.

Influence of test temperature on impact toughness of X70 pipe steel welds

Abstract: Impact toughness of the base metal and welds of the pipe steel of the X70 strength class was investigated and high values were defined. It was particularly important that impact toughness of the weld at temperatures of -40 °C and -20 °C was identical to that of the base material. For specimens W1 and W2 cut from the heat zone of weld by different metods (milling (W1) and plasma method (W2)) at a temperature of -40 °C, it was 1.14 and 1.5 times lower than that of the base metal, respectively. The method of cutting the specimens (milling, or plasma cutting) did not affect the impact toughness of the pipe steel and its welds in the investigated temperature range.

The role of notch tip shape and radius on deformation mechanisms of 12Cr1MoV steel under impact loading. Part 2. Influence of strain localization on fracture and numeric simulations

Abstract: The fracture energy of 12Cr1MoV steel specimen with V-shaped, U-shaped and I-shaped notches under impact loading was measured and analysed. The results were described using three common approaches to ductile-brittle fracture: force-based, energy-based and strain-based. Within the stage-wise approach of physical mesomechanics of materials, the rate of increase/decrease of load at the stage of initiation and propagation of a macroscopic defect was evaluated, providing a good correlation with the work of fracture. The excitable cellular automata technique was applied to simulate the deformational behaviour of the specimens with different shape of notches. It was demonstrated that in the case of the blunted notch, the maximum impact toughness is facilitated by a more uniform distribution of the load along the notch, which hinders brittle fracture at lower testing temperature. For the specimen with the sharp I-notch, the bands of localised shear are oriented normally to the loading axis, inhibiting macroscopic localisation of strain and crack propagation. For this reason, the impact toughness of the specimen with the I-notch appeared to be higher than that of the V-notched one. Using the fractographic analysis and the size of shear lips as a quantitative fracture parameter, a physical-mechanistic scheme of fracture was suggested for the case of enhanced localised plasticity near the stress riser.

Minimizing Losses During Natural Gas Transportation

Abstract: Abstract The processes of supplying natural gas are accompanied by significant losses. In this regard, the complex problem of minimizing losses and improving the efficiency of energy use is very relevant. Steel pipelines for transportation of oil and gas often cross the tracks or are located parallel to the lines of electric power transmission lines of alternating current. Most dangerous from the corrosive point of view of the combination of the chemical composition of the soil electrolyte and the vagal current density were established.

Modeling and Signals Processing Using Cyclic Random Functions

Abstract: The paper considers the unified approach to the modeling and processing of heart signals of electrical, magnetic and acoustic (mechanical) nature based on the model of the theory of cyclic random functions, namely, using cyclic random process and vector of cyclic rhythmically related random processes. Installed a fact of considerable sensitivity of estimates mathematical expectation and coefficients of its decomposition in Fourier series, to the change in the cardiovascular system of humans, indicating the possibility of their use as diagnostic features in automated systems cardiac diagnosis. Installed a fact of significant sensitivity of the estimation of the mutual correlation function and the coefficients of its decomposition in the two-dimensional Fourier series, to the change in the state of the cardiovascular system of a person, indicating the possibility of their use as diagnostic features in automated systems of complex cardiology. This approach due account of stochasticity, cycling, synchronized signals hearts, changing time intervals between the single-phase values in different cycles of signal heart, made it possible to improve accuracy, reliability and informativeness of the automated diagnosis of the functional state of the heart.

Implementation technology software-defined networking in Wireless Sensor Networks

Abstract: Recent advances in the micro electromechanical systems technology MEMS, wireless communications and digital electronics allowed to create inexpensive, low-powered, multi-functional nodes. They are small and "talk" directly with each other. Wireless Sensor Network (WSN) is considered to be a distributed, self-organizing system of a large number of sensors and assistive devices that communicate with each other through the radio channel. Sensor networks are based on the joint work of a large number of tiny nodes that consist of data collection and processing modules and a transmitter or a transceiver. Such networks have significant advantages over the set of traditional sensors. The main problem in sensor networks is a short stint due to high power consumption and the incompatibility of various hardware. Because of the absence of a clear standardization in sensor networks, there are several different platforms. All platforms meet the essential basic requirements for sensor networks: low power consumption, long operating time, low-power transmitters and presence of sensors. Each platform is in its own interest substantiated and has its own peculiarities. They will transmit the observation data to the central nodes where data collection, storing, and processing will be performed. The main purpose is to enhance the security wireless sensor networks.