Iryna Dolinska

• Doctor of Engineering Sciences
• Karpenko Physico-Mechanical Institute Nasu

A method for estimating the residual life of X70 steel pipe of an oil pipeline with an external surface semi-elliptical crack, in which there is a laminar flow of oil under a pressure of 12 MPa, and a soil corrosive medium penetrates the crack, is proposed. The residual life of such a pipe after 33 years of operation, when corrosion-hydrogen degrad...

A developed method for determining the lifespan of structural elements with large-scale cracks of complex geometry under the influence of long-term static loads and corrosive environments. The method is based on an appropriate computational model, which relies on the first law of thermodynamics for the elementary act of local failure (crack propaga...

We propose a mathematical model for the determination of the period of subcritical crack growth in an oil pipeline operating under the action of constant internal pressure, hydroshocks, and soil corrosion with regard for the degradation of its material. The model is based on the first law of thermodynamics, i.e., on the balance of energy components...

The accuracy of the damage and the outcome of the battle depend on the durable wear resistance of the inner surface of the artillery barrels. When fired, there is close contact between the surface of the barrel and the rings of softer metal on the projectile (this is for the tightness of the system), which leads to their active abrasion. True, the...

The monograph considers the issue of forecasting the lifetime (residual lifetime) of oil and gas pipeline pipes, taking into account the conditions of operation and degradation of their materials. The condition of operated oil and gas pipelines was analyzed. The conditions and modes of operation are described, as well as their influence on the dama...

The authors proposed a mathematical model for estimating the timespan life of an oil pipeline with a surface semi-elliptical microcrack under the turbulent flow of oil in a soil-corrosive environment, which leads to the degradation of the pipe material. A two-frequency load models the effect of the turbulent flow of oil on the pipe wall. The energy...

A mathematical model is proposed for estimating the period of subcritical growth of a high-temperature creep crack in materials subjected to neutron irradiation and long-term static loading. The model is based on the energy approach regarding the balance of energy components and the balance of the rates of change of energy components. By presenting...

The purpose of this study is to build mathematical models for kinetics description of small fatigue crack propagation under mode II and mode III loading, as well as to determine the period of their subcritical growth. To achieve this, a problem is formulated to determine subcritical growth periods of small fatigue cracks in a thick infinite plate w...

Based on the modern theory of fatigue and the energy approach, a method has been developed for (residual) lifetime prediction of field sprayer booms under manoeuvre loading and corrosive-aggressive environment. A computation model has been built for (residual) lifetime determination of a long-range field sprayer boom under manoeuvre loading that co...

Based on the energy approach formulated earlier by the authors, the calculation model for determining the durability of a fiber-reinforced concrete beam under long-term pure bending and local creep was developed. The model relied on the first law of thermodynamics regarding the energy balance and the balance of rates of energy variations in the fib...

Applying the laws of thermodynamics, a general energy approach is formulated to study the delayed fracture of structural materials under the action of force load (static, cyclic, shunting mode of its change), high temperatures, hydrogen-corrosive media, neutron irradiation. Based on the energy approach process, models and forecasting methods of res...

We propose a computational model for the evaluation of the residual service life of spraying booms of the field sprinklers in the maneuvering loading mode (stationary oscillations of sections of the boom together and separate shocks caused by the irregularities of the field surface). This model is based on the energy approach earlier developed by t...

We propose a computational model for the evaluation of the service life of fiber-reinforced concrete structural elements subjected to long-term tension. The model is based on the first law of thermodynamics and a proposed idealized tensile stress-strain diagram of fibrous concrete. This model is used for the evaluation of the service life of a fibe...

Purpose: The aim of the proposed research is to create a calculation model of surface fatigue crack growth at the axle of railway wheelset working under operational loads. Design/methodology/approach: The energy approach of the fracture mechanics was used to formulate the calculation model of fatigue crack propagation at the wheelset axle surface....

Analytical researches of growth of internal surface cracks in oil pipeline pipe wall under real conditions of operation and determination of its residual service life were carried out. The analysis of the operating conditions of the pipeline was carried out during the research. It is believed that the flow of oil is turbulent with possible hydrauli...

We proposed new procedures for the evaluation of the residual service life of main pipelines with surface cracks under the action of a long-term constant gas pressure in gas pipelines, a variable pressure in oil pipelines, hydrogenation, and soil corrosion. The degradation of the materials is taken into account. Since the time dependence of the deg...

The proposed survey is devoted to the analysis and synthesis of the results of investigations of the deformation and fracture of fiber-reinforced concretes. We present a survey of the following aspects of this problem: development and application of fiber-concrete technologies, basic parameters of the structure of fiber concretes and specific featu...

A method for the evaluation of the residual service life of a disk of steam turbine is proposed with regard for the startups and shutdowns in the process of operation (maneuvering mode) on the basis of the energy approach. The method was approved by determining the periods of operation when the startups and shutdowns of the turbines are especially...

We analyze the results of investigations of the acoustic-emission diagnostics of corrosion defects in materials and establish the relationship between the total count, energy, amplitude of acoustic radiation and the corrosion cracking of steels and metal alloys. Examples of application of the acoustic-emission method to detection of corrosion defec...

Estimation models (differential equations, initial and final conditions) for determining the crack propagation kinetics in hydrogen-containing environments using the acoustic emission (AE) signal parameters are proposed. The formulation of these models is based on the main ideals of the AE method, dependence between the crack increment area and a s...

We develop computational models aimed at the determination of the residual service life of two-layer plates with systems of cracks under long-term static loads at high temperatures. The models are based on the first law of thermodynamics of energy balance for the components and rates of their changes in a metallic two-layer body containing macrocra...

We formulate a mathematical model for the investigation of the processes of propagation of creepfatigue cracks in plates under block loading. The influence of the shape of loading blocks on the durability of structural elements is investigated and the the subcritical growth of creep-fatigue cracks in thin-walled structural elements is analyzed.

We describe the procedure of diagnostics of the initiation and stable propagation of fatigue fracture in alloy of the Al–Zn–Mg–Cu system based on the specific features of generation of the acoustic emission in the process of initiation and growth of fatigue cracks in 1973-T2 aluminum alloy. It is shown that the character of emission of the AE signa...

The calculation procedure for the period of subcritical fatigue crack growth near the lower design-envisaged hole of the pivot joint-coupled bogie frame of the electric locomotive is proposed. The procedure is based of the calculation model of the fatigue crack growth built on the energy conservation law in thermodynamics. Unknown mechanical charac...

We propose a computational model aimed at finding the service life of a gas pipeline containing a surface corrosion crack under the action of long-term pressure discontinuous as a function of time (maneuvering mode of operation) and in the presence of hydrogenation of its wall. The model is based on the energy approach developed earlier by the auth...

Purpose. The problem of determining the residual life of frame bogie elements of locomotives is a great importance for predicting their work safely and avoidance potential failures on the track. This especially concern cases when such elements have creep-fatigue cracks which grow under action of cyclic loading with excerpts T1 in the cycle and reac...

We formulate a mathematical model for the determination of the effect of hydrogen on the period of initiation of creep-fatigue macrocrack in the vicinity of a stress concentrator in a plate. By using this model, we find the period of initiation of a macrocrack for a strip with two side notches under cyclic loads, high temperatures, and the action o...

We determine the period of subcritical growth of low-temperature creep cracks according to the parameters of acoustic-emission signals and develop a method for the construction of the kinetic diagrams of growth of low-temperature creep cracks by the acoustic-emission method.

The procedure for energy approach-based estimation of the subcritical growth period for a high-temperature creep crack in a two-layer plate is proposed. The validity of the procedure is illustrated by the example of central crack extension in the plate.

We formulate a mathematical model for studying the processes of fracture of plates with systems of cracks under long-term static breaking loads and high temperatures. Using the solutions of this problem, we calculate the residual lifetime of a plate with periodic and biperiodic systems of cracks.

We propose a computational model for the investigation of the process of growth of high-temperature creep cracks under long-term tensile static loads (dynamic mode of operation) and determine the residual service life of a steam pipe under these operating conditions. It is shown that the indicated loads may lead to the unpredicted fractures of stru...

A computational model is proposed for the determination of the service life of structural elements with concentrators under the conditions fatigue and high-temperature creep. The model is based on the energy approach and the representation of the service life of a structural element as the sum of the periods of initiation and subcritical growth of...

On the basis of a computational model of propagation of creep fatigue cracks in thin-walled structural elements proposed earlier, we formulate a new computational model and use this model to develop a method for the evaluation of the residual service life of wheels of steam turbines. The residual lives of the annular and circular wheels of a steam...

We construct the kinetic equation for the period of growth of a creep fatigue crack. By using the experimental data, it is shown that this equation correctly describes the behavior of the crack. It follows from the solution of Sack’s problem that the larger the duration of the loading cycle T, the more pronounced the effect of creep and, hence, the...