D.V. Breslavsky

National Technical University "Kharkiv Polytechnic Institute" | KhPI · Computer Modeling of Processes and Systems

An approach to the analysis of the influence of impact loading on creep, accumulation of hidden damage and fracture of structural elements made of functionally graded materials (FGM) is proposed. The approach is based on the analysis of additional damage caused by the impact loading and the stress redistribution caused by it. For the numerical mode...

Статтю присвячено опису методу двовимірної апроксимації даних за допомогою алгоритмів методу зважених відхилів з кусково заданими базисними функціями у реалізації методу скінченних елементів. Надано математичну постановку задачі та основні співвідношення методу для двовимірних областей. До моделювання залучено трикутний скінченний елемент. Наведено...

The paper contains a description of the approach, algorithms, and software tool for image analysis of deformed material structures. The developed approach is based on the analysis of the microstructure of the material to identify important factors that affect high-temperature deformation during creep in a heat-resistant nickel-based alloy, namely,...

The approach to modeling the stress‐strain state during creep damage processes in long beams, which receives an impact loading on their surface, is presented. Both problems are solved by use of the finite element method (FEM). Stress distributions obtained in impact solution are further used as additional initial conditions in the analysis of the e...

An approach to modeling creep fracture under a complex stress state using the Finite Element Method is proposed. The model of the turbine blade root was studied. The methodology of the transition in the analysis from the general 3D to the 2D stress state is proposed. For the models of the roots, the characteristics of the damage accumulation were o...

An approach that allows using the qualitative results of the analysis of the so-called "mechanism based" evolution equations, i.e. constructed using experiments at the micro- and meso-level, to determine the structure of the equation for another, similar in composition, material, is proposed. To determine damage due to irradiation influence, the cl...

The formulation of the problem and the basis of the method for solving two-dimensional creep problems for the case of finite strains are presented. The method is based on the Arbitrary Lagrange-Euler (ALE) approach in numerical modeling using FEM. The method is implemented in the form of additional units to the creep calculation software. The plane...

Computational and experimental approaches to determine the values of physical and mechanical properties of three-layer sandwich plates, consisting of two outer layers of fiberglass and a core of expanded polystyrene, bonded with epoxy glue, is proposed. To measure displacements and strains, an experimental stand which uses mechanical dial gauges an...

The paper concerns with the presentation of the approach to the modeling of wear processes in creep conditions. The power value of the friction forces, which varies over time due to the stress redistribution during creep, is analyzed. An approach to the determination of the wear coefficient under creep conditions is proposed. The model problem of t...

Статтю присвячено опису постановки задачі, підходу до моделювання та отриманим результатам з повзучості товстої труби при її контакті зі стрижнями напівциліндричного перерізу, які розташовані симетрично її центру. Представлено огляд наукових публікацій, виконаних у напрямку моделювання контакту при повзучості, в тому числі з використанням МСЕ. Пост...

A description of the design, control system, and software implementation of the thermal mode control of the experimental creep testing machine developed at the National Technical University "Kharkiv Polytechnic Institute" is given. As a result of testing the automated temperature control system, the main characteristics of the system were establish...

A description of the developed software for saving and analyzing data on high-temperature deformation and long-term strength of metallic materials is provided. The open source Laravel web framework was chosen to implement in the application. The Voyager solution is used together with it as a graphical interface for interacting with the database. A...

The issue of determining the stress-strain state during creep in models of rotors of steam and gas turbines is considered. The formulation of the problem is based on the general approach of Solid Mechanics using incremental theory to describe creep strains. The Finite Element Method was used as a solution method in the implementation of professiona...

The paper presents an approach to determining the level of creep deformation and long-term strength of structural elements that operate under conditions of cyclic loading and heating. The method for solving the boundary - initial value problem is described. It is based on the combination of FEM and difference methods of integration for initial prob...

The paper is devoted to the presentation of the calculation method for determining the stress–strain state and long-term strength of reactor vessel internals (RVI) and the description of the results obtained with its help. The method is based on a complete mathematical formulation of the boundary- initial value problems of creep accompanied by irra...

The paper presents an approach for effective solution of the stress-strain state and wear prediction problem for the case of contact between fuel rod and grid surfaces of a nuclear reactor. Boundary-initial value elastic-plastic problem statement, due to the quasi-static character of the forced oscillations, which was approved by eigen frequencies...

This paper reports a method that numerically models the deformation and accumulation of hidden damage in structural elements that are in an inhomogeneous thermal field and are exposed to radiation. Materials considered are those exhibiting orthotropy (transversal isotropy) of long-term properties. The problem is stated as an boundary – initial valu...

COMPUTER SIMULATION OF THE DEFORMED STATE AND STRENGTH OF THE FRAME STRUCTURE OF A HEAVY UAV The paper is devoted to the presentation of the computer simulation results of the stress-strain state and evaluation of the low-cycle strength of the frame structure of a heavy unmanned aerial vehicle (UAV) of the quadcopter type, the prototype of which wa...

Статтю присвячено підходу та аналітичним методам прогнозування змінювання власних коливань балок в умовах дії сил поздовжнього розтягу при повзучості. На базі класичного рівняння коливань балок при розтязі отримано метод оцінювання власних частот, які можуть змінюватись при повзучості. Отримано вирази для поздовжньої сили, що залежить від фізико-ме...

the quasi-static problem is discussed. The equations of the incremental theory of plasticity are used to describe fast deformation. The numerical simulation method is implemented based on the use of the Arbitrary Lagrange-Euler (ALE) approach, in which the sequence of boundary value problems in the current configuration of the solid is solved using...

Fracture of a thin-walled conic aluminium shell under the action of the belt explosive charge is analyzed numerically. Initial stress-strain state of the shell is determined by using shell finite elements. This state is used as initial conditions of the band, which is cut from the shell along generating lines. 2D initial-boundary value problem of t...

A method for determining the effect of inhomogeneous temperature distribution, irradiation damage, irradiation swelling, irradiation creep of the material on the long-term strength of reactor in vessel internals and their deformation has been developed. The deformed state of the WWER type nuclear reactor baffle was determined. Constitutive equation...

Approaches for describing the deformation of structural elements made from the material, in which radiation creep and swelling strains develop simultaneously, are discussed. The technique for description of irradiation swelling strains, which is used for calculational analysis of stress-strain state arising in structural elements under the joint ac...

The paper presents the formulation of a two-dimensional problem of the creep theory for the case of finite strains. A description of the foundations of the calculation method presents. The method is based on the use of the generalized Lagrange-Euler (ALE) approach, in which the boundary value problem in the current solid configuration is solved by...

Long-term strength investigations of construction elements made of reinforced concrete (RC) under creep conditions are considered. A calculation method that allows determination of the load-bearing capacity and long-term strength of RC thin-walled elements under short- and long-term loading is proposed. The method is based on a combination of the f...

The paper describes the method for numerical simulation of stress–strain state variation in the structural elements of nuclear reactor under creep and swelling conditions. The mathematical statement of the initial–boundary value creep problem is presented. The constitutive equations account the radiation swelling, creep, and damage accumulation in...

The main approaches and methods for studying creep and long-term strength of thin-walled structures made of concrete and reinforced concrete are considered. A mathematical formulation and a method for solving the creep-damage problem of thin-walled concrete elements under short-term and long-term loading, which makes it possible to determine their...

Closed-form analytical representations of the rigid body orientation quaternion, angular velocity vector and the external moment vector satisfying kinematic equations and equations of motion are derived. In order to analyze errors of orientation algorithms for strapdown inertial navigation systems, reference models for specific rigid body rotation...

Creep-damage processes in notched specimens subjected to static and periodic loading are studied experimentally. Subsequent simulations were carried out using Rabotnov evolution equation. In case of dynamic creep (fast periodic loading) the constitutive equations derived by use of asymptotic and averaging methods were used. Numerical results were o...

The paper contains the description of the approaches and algorithms for simulation and control of motion of anthropomorphic robot. The different stages of motion design as well as AI use for control are discussed.

The statement and solution method of the two-dimensional problem of orthotropic creep under static and periodic loadings are presented. Experimental investigations of short-term deformation under uni-axial and plane stress states are carried out. Short-term creep curves were obtained for uni-axial specimens and plates with holes. Constitutive equat...

Creep constitutive equations have been derived for the materials that exhibit the properties of orthotropy (transversal isotropy) and transient creep under cyclic loading. A low-frequency case is considered. The paper provides results of experimental studies of the short-term creep of St3 steel under static and stepwise cyclic loading at room tempe...

Deformation and damage of nuclear power station fuel element shells under irradiation and cyclic loading due vibrations are studied. Constitutive equations include dependencies for a creep-damage equation with a scalar damage parameter, as well as terms for thermal and irradiation creep strains, elastic, thermal, and swelling strains. The accelerat...

The paper presents a method for determination of the stress-strain state and the level of accumulated damage in polymer parts of the devices aboard artificial satellites orbiting the Earth. A mathematical statement of the creep problem is put forward using the Lagrange approach. The methods involves the use of constitutive equations that include el...

The aim of this paper is the analysis of inelastic behavior under periodic cyclic loading regimes for materials showing recovery effects. Starting with the Armstrong–Frederick type model and applying the two-time-scale asymptotic technique, the constitutive equation for the mean inelastic strain rate and the evolution equation for the mean backstre...

Approach for numerical simulation of the process of the creep crack growth taking into account the hidden material damage is proposed. The approach is based on the application of finite element creep modeling, accompanied by damage. For calculations, the FEM Creep software package is used. Using the proposed algorithm for rebuilding the grid with t...

The deformation and fracture of impact loaded thin steel square plates is studied experimentally and numerically. Impacts with low velocities (10–15 m/s) are calculated and an inductive machine (IM) is used as an impact loading device in a developed experimental unit. Impact tests are made for different velocities which correspond to the cases of e...

Numerical-analytical models of the nonstationary thermal process and the associated with it measurement errors were designed and investigated for fiber-optic gyroscopes (FOG). The models were used for simulating output data of the measuring gyroscopic module (MGM) consisting of a FOG of the studied type at arbitrarily assigned operation temperature...

The description of algorithms and software for Finite Element Method data preprocessing, which is designed for solution the problems of Solid Mechanics, is presented. Three dimensional Finite Element models for prismatic solids are regarded. For the case of large strains the arbitrary Lagrange-Euler approach is used. Two approaches which are realiz...

The paper is devoted to description of the software, which made as web-application, for collection, storing and processing the data of creep and long term strength, including the case of creep-fatigue interaction. The short review and analysis of problem is presented. The technology for minimization of creep data storing as well as the architecture...

The paper presents the description of methods, algorithms and software were developed for numerical simulation of two- and three-dimensional creep-damage problems. Special attention is stressed on the problems of solid’s behavior at conditions of cyclic varying of stress and temperature fields which is widely spread in modern aerospace and power in...

A method is described to calculate creep and damage in structural elements under cyclic loading. Materials exhibiting anisotropic creep-damage behavior are considered. The results of calculating the deformation and fracture of structural elements at a plane stress state are presented.

The paper contains the equations of steel beam flexural oscillations which were obtained considering creep strains. Approximated solution had been obtained by use of Galerkin method, solution for reduced model had been found by numerical integration. Numerical data are discussed.

Creep of cyclically loaded bodies and their fracture due to creep mechanisms are studied. Creep damage equations are built by use of tensor parameter for titanium alloy. Similar equations were derived for stress cyclic varying using the method of asymptotic expansions and averaging in a period. 2d plane stress problems were solved by FEM and fields...

Results of experimental and numerical investigations of impact loading of circular glass and composite aluminum plates are presented. Single for glass and repeated impact loading tests for aluminum plates were performed. The numbers of cycles to failure at the case of cyclic impacts were determined. The data of experimental investigations were used...

The new method of solving thermal creep problems, accounting for cyclic variations of external force and thermal fields was put forward. Asymptotic expansions and period averagings were used to derive the systems of basic and auxiliary equations. The equation of state for cyclic thermal creep was proposed and validated. Numerical simulation of the...

We present a method for solving problems of high-temperature cyclic creep and damage accumulation in structural elements. The asymptotic expansion and averaging techniques both over the period of forced vibrations of a body and that of slowly varying loads are used for the set of equations describing the creep and damage processes in thin-walled st...

The models for description of creep-damage behaviour in materials and thin shallow shells and plates deforming in conditions of joint action of static and fast cyclic load are given. The properties of the proposed material model were established by comparison of experimental and numerical data. The method for numerical simulation by in-house code o...

The models for description of creep-damage behaviour in materials and thin shallow shells and plates deforming in conditions of joint action of static and fast cyclic load are given. The properties of the proposed material model were established by comparison of experimental and numerical data. The method for numerical simulation by in-house code o...

Thin-walled structural elements are often subjected to cyclic loadings. This paper presents a material model describing creep behaviour under high-cycle loading conditions (N greater than or equal to 5 x 10(4)-10(5)). Assuming that the load can be split into two joint acting parts (a static and a superposed, rapidly varying small cyclic component),...

Thin-walled structural elements are often subjected to cyclic loadings. This paper presents a material model describing creep behaviour under high-cycle loading conditions (N ≥ 5 × 104-105). Assuming that the load can be split into two joint acting parts (a static and a superposed, rapidly varying small cyclic component), the asymptotic expansion o...

We propose a method for the investigation of creep and long-term strength of statically and cyclically loaded elements of power-generating units. We present the results of numerical analysis of creep and fracture of herringbone lock joints of the blades of the second stage of gas-turbine engines as well as of their stress-strain state and accumulat...

Problem statements and methods of nonlinear creep investigations for bodies failing as a result of creep under the joint action of static and cyclic loads are described. One and two-dimensional plane models are presented. Creep and failure numerical examples for continuous plates with a small hole under their in-plane cyclic loading are considered.

A method for calculating creep and fatigue limit under static and cyclic loading the power machine components is suggested. The numerical analysis of fracturing the blade root of gas turbine engine second step is given. Stress-strained state and damage accumulation due to creep are analyzed. The essential influence of high-cyclic loading on stress...

The creep of structures is a nonlinear mathematical problem and the adequate simulation of creep processes involves several difficulties. In order to overcome them, computer numerical methods involving three simulation steps which are all equally important have been used: accurate simulation of the kinematic (possibly nonlinear) and the quasi stati...

The aim of the paper is the presentation of a suitable strategy which enables us to analyses complex problems such as creep of structural members and combines both the important aspects, efficiency and accuracy, in numerical computations. This representation enables us two approaches to models for evaluating the stress-strain state under creep cond...