Numerical model of the mechanical behavior of coated materials in the friction pair of hip resurfacing endoprosthesis

The paper is devoted to the theoretical study of the mechanical behavior of materials in the friction pair of hip resurfacing endoprosthesis. The investigation was based on three-dimensional computer simulation by the movable cellular automaton (MCA) method, which is a representative of the methods of particles in the mechanics of materials. The results indicate the promising use of metallic alloys with biocompatible ceramic coatings in friction pairs to increase the service life of hip resurfacing

3D modelling of material flow in friction stir welding using movable cellular automaton method

The paper is devoted to the theoretical investigation of the peculiarities of material flow taking place in friction stir welding (FSW). The investigation was based on 3D computer simulation by the movable cellular automaton (MCA) method, which is a representative of the particle methods in mechanics of materials. Usually, material flow in FSW is simulated based on computational fluid mechanics, which assumes that the material is a continuum and does not take into account the material structure. MCA considers a material as an ensemble of bonded particles. Breaking of inter-particle bonds and formation of new bonds enables simulation of crack nucleation and healing, as well as mas mixing and microwelding. The simulation results showed that using pins of simple shape (cylinder, cone, pyramid) without shoulder results in small scattered displacements of the plasticised material in the workpiece thickness direction. Nevertheless, the optimal ratio of the longitudinal velocity to the rotational speed allows transporting of the welded material around the pin several times and producing the joint of good quality. Applying additional ultrasonic vibration to the pin may lead to better mixing of the plasticized material behind the pin

Role of vortex-like motion in contact loading of strengthening coating. Movable cellular automaton modeling

Movable cellular automata (MCA) is an efficient numerical method in particle mechanics, which assumes that any material is composed of elementary objects interacting among each other according to many-particle forces. In this paper MCA method is applied to modeling deformation of 3D coating-substrate system under its contact loading by rigid indenter. Main attention of the research is focused on the role of vortex-like structures in the velocity fields in deformation of the strengthening coating and substrate. The mechanical properties of model coating correspond to multifunctional bioactive nanostructured film (TiCCaPON) and the properties of substrate, to nanostructured titanium. Loading is performed by hard conical indenter. The peculiarities of velocity vortex formation and propagation, as well as its interaction with structural elements are studied. One of possible application of the study is non-destructive technique for detecting nanoscale defects in surface layer of a material using frequency analysis of the force resisting to sliding of a small counter-body on the material surface, known as tribospectroscopy. Possibilities of this technique are studied based on 3D modeling by MCA method for the above mentioned coating with nano-pores. It is shown that specific peaks at the friction force spectrum correspond to different geometrical characteristics of the nano-pores

Identification of nanosized defects using tribospectroscopy. Modeling by movable cellular automaton method

The work describes the application of the movable cellular automaton method for the simulation of typical situations of nano-scale crack identification in ceramic coatings by the spectral analysis of friction force continuously registered using a small counter-body moving over the coating surface. It is shown that the Fourier spectra of the friction force have peaks that correspond to the distance between the nanocracks oriented perpendicular and at some angle to the tested surface. The obtained results allow to conclude that the appearance of cracks on the Fourier spectra of friction force depends on their orientation. Thus, the distance between cracks, their orientation and sizes can be identified by the method of tribospectroscopy

Identification of nanosized defects using tribospectroscopy. Modeling by movable cellular automaton method

The work describes the application of the movable cellular automaton method for the simulation of typical situations of nano-scale crack identification in ceramic coatings by the spectral analysis of friction force continuously registered using a small counter-body moving over the coating surface. It is shown that the Fourier spectra of the friction force have peaks that correspond to the distance between the nanocracks oriented perpendicular and at some angle to the tested surface. The obtained results allow to conclude that the appearance of cracks on the Fourier spectra of friction force depends on their orientation. Thus, the distance between cracks, their orientation and sizes can be identified by the method of tribospectroscopy

MULTILEVEL NUMERICAL MODEL OF HIP JOINT ACCOUNTING FOR FRICTION IN THE HIP RESURFACING ENDOPROSTHESIS

Friction between the moving parts of the endoprosthesis has a significant impact on the endoprosthesis operation time. Primarily, it concerns the endoprosthesis of hip and knee joints. To improve the tribological characteristics of the metal endoprosthesis, hardening nanostructured coatings are used. Usually, titanium and titanium alloys are used as metal, and titanium nitride is used as a coating. Herein, we propose an approach to multilevel modeling of the system “bone-endoprosthesis” which is based on the movable cellular automaton method and accounts for friction between the moving parts of the hip resurfacing endoprosthesis. We validated the models of the friction system materials using the instrumented scratch test simulation. Then, we simulated friction at the mesolevel, explicitly considering roughness of the coating. The results obtained at the mesolevel were used as tribological characteristics of the coating in the macroscopic model of the hip resurfacing endoprosthesis

Elastic vortex displacements as precursors of mechanical stress relaxation in heterogeneous materials

Deformation of heterogeneous material containing internal interfaces or/and free surfaces is accompanied by collective vortex motion near such boundaries. Nevertheless, such fundamental factor as elastic vortex motion in material formed during dynamic loading still remains out of the discussion. The aim of this paper is to reveal the role of vortex displacements in contact interaction of heterogeneous coatings with hard counter-body by means of 3D computer simulation using movable cellular automata. The research is mainly focused on the role of vortex structures in the velocity field in elastic and non-elastic deformation of the coating. The peculiarities of the velocity vortex formation and propagation, as well as interaction with the structural elements are studied

Study of the influence of morphology and strength of interphase boundaries on the integral mechanical properties of NiCr-TiC composite

Sintered metal-ceramic materials are characterized by high mechanical and tribological properties. A key element of the internal structure of the metal-ceramic composites which have an important, and in many cases, a decisive influence on the integral mechanical properties of these materials is the interphase boundary. In this paper, based on numerical simulation we show the influence of morphology and strength properties of interfaces for integral mechanical properties of the dispersion-reinforced composite NiCr-TiC (50 : 50). Computer simulation results indicate that the phase boundary significantly contributes to the integral mechanical characteristics of a composite material and to the nature of the initiation and development of cracks

3D modeling of the mechanical behavior of ceramics with pores of different size

Movable cellular automaton method was used for simulating uniaxial compression of 3D porous ceramic samples. Pores were considered explicitly by removing randomly selected automata from the original FCC packing. Distribution of pores in space, their size and the total fraction were varied. It is shown that the relation between mechanical properties of the material and its porosity significantly depends on the pore size. Thus, value of the elastic modulus of the samples with large pores is greater than that of the samples with small pores by average value of 3%-16%. Strength value of the samples with large pores is less than that of the samples with small pores by average value of 12% up to the porosity of 0.55, and then becomes to be greater. When the samples contain small and large pores there is a maximum of mechanical properties at ratio of volumes of large and small pores of about 0.75

Vectors of the Development of Information Warfare Linguistics

В статье отражено видение ее авторами перспектив развития лингвистики информационно-психологической войны. Сначала дается небольшой экскурс в формирование лингвистики информационно-психологической войны и отмечается вклад ученых СФУ в становление и развитие этого направления; актуальным признается разработка лингвистики противодействия в информационно-психологической войне. Далее намечаются основные междисциплинарные векторы будущих исследований, связанных с изучением информационно-психологических войн в аспекте лингвистики противодействия: аналитико-дискурсивный вектор (выявление деструктивных смыслов, продвигаемых в дискурсах различного типа; лингвистический анализ дискурсивной реализации стратегии противостояния деструктивным воздействиям; анализ научного дискурса об информационно-психологических войнах); лингвотехнологический (лингвистическое сопровождение разработок в области искусственного интеллекта); лексикографический (создание терминологического словаря лингвистики информационно-психологической войны, словарей языка войны); лингвовалеологический (исследование речевых приемов, оказывающих влияние на психическое здоровье человека, валеологичности пропаганды), лингвоэкологический (изучение языковой ситуации в аспекте лингвоэкологической безопасности; языковых последствий информационно-психологической войны), лингвометодологический (разработка комплексной методики анализа дискурса информационно-психологической войны) и лингвоаксиологический (изучение отражения в дискурсе ценностных категорий). Обращается внимание на взаимосвязь различных векторов лингвистики противодействия, объединяющим для которых выступает понятие информационно-психологической безопасностиThrough a brief survey of the typical definitions of information warfare, the article illustrates the authors’ views on the perspective investigation of the linguistic aspect of the phenomenon. The introduction engages with the shaping of the information warfare as a way to set the broader analytical context. It further reviews the contribution of the SibFU linguists into its formation and the importance of finding the ways to respond to the information warfare in terms of conducting multidisciplinary linguistic research. The authors specify the possible vectors for it: analytical and discourse vector (investigating the destructive messages and meanings in various types of discourse and narratives, linguistic analysis of the discourse strategy to counter destructive information, the academic discourse analysis on information warfare); lingo-technological vector (linguistic support of AI research); vocabulary vector (compiling information warfare dictionaries); lingo-valeological vector (investigating the influence of speech acts on human psychology); lingo-ecological vector (investigating language development in terms of lingo-ecological security, the language repercussions of information warfare); lingo-methodological vector (developing the complex method of information warfare discourse analysis); lingo-axiological vector (tracing information warfare in speech representation of moral as well as social values). The article also highlights the importance of the linguistic research in the information security real