PNRPU Mechanics Bulletin最新文献

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DEPOSITION OF FULLERITES C60 ON A SOLID SUBSTRATE TO FORM A FILM 在固体衬底上沉积富勒石以形成薄膜
PNRPU Mechanics Bulletin Pub Date : 2023-12-15 DOI: 10.15593/perm.mech/2023.1.12
C. В. .. Суворов, А.В. Вахрушев, Alexander V. Vakhrushev, S. Suvorov, ©. Pnrpu
{"title":"DEPOSITION OF FULLERITES C60 ON A SOLID SUBSTRATE TO FORM A FILM","authors":"C. В. .. Суворов, А.В. Вахрушев, Alexander V. Vakhrushev, S. Suvorov, ©. Pnrpu","doi":"10.15593/perm.mech/2023.1.12","DOIUrl":"https://doi.org/10.15593/perm.mech/2023.1.12","url":null,"abstract":"The use of C60 fullerites to create films on the surface of a solid substrate can be used not only to create coatings, but also to modify the surface layer of the substrate, which from a practical point of view can be in demand in such sectors of the economy as machine and instrument engineering. To analyze the process of formation of fullerite films on the substrate surface, a computer experiment was carried out, but the behavior of not a single fullerite or fullerene, as it was implemented in previous works of the authors, but a significant number of C60 fullerites deposited in the modeling area over a certain time interval and forming a \"flow\" was modeled. The substrate of the solid was an iron crystal Fe(100). The substrate temperature in the study was kept constant at the following values – 300 K, 700 K, 1150 K. The initial parameters of each individual fullerite were determined stochastically within the specified limits. The software package used to conduct the described computer experiment was – LAMMPS. The interaction of the atoms of the system with each other, during the simulation, was determined by the multiparticle potential (MEAM is a modified submerged atom method). The main result of the conducted computer experiment is that it was possible to simulate the deposition of C60 fullerites with the formation of a film on a solid substrate. The main regularities of the interaction of fullerite as a whole and fullerenes forming it, both with the substrate and with other fullerites forming the film, were revealed. And the analysis of changes in temperature and potential energy of the system, both during the deposition of fullerites and after its completion, allows us to talk about the stability of the resulting fullerite – substrate system.","PeriodicalId":38176,"journal":{"name":"PNRPU Mechanics Bulletin","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48456841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
SPECTRAL DYNAMIC STIFFNESS METHOD FOR THE FLUTTER PROBLEM OF COMBINED PLATES 组合板颤振问题的谱动刚度法
PNRPU Mechanics Bulletin Pub Date : 2023-12-15 DOI: 10.15593/perm.mech/2023.1.09
S. Papkov, Yu. I. Papkova, V. Pasechnik
{"title":"SPECTRAL DYNAMIC STIFFNESS METHOD FOR THE FLUTTER PROBLEM OF COMBINED PLATES","authors":"S. Papkov, Yu. I. Papkova, V. Pasechnik","doi":"10.15593/perm.mech/2023.1.09","DOIUrl":"https://doi.org/10.15593/perm.mech/2023.1.09","url":null,"abstract":"At present time, the spectral dynamic stiffness method is being actively developed as an alternative to the finite element method for vibration and stability problems of composite structures from beams, rods, plates and shells. This approach, based on exact solutions of governing differential equations, makes it possible to more effectively study the problem in the medium and high frequency ranges, and gives analytical expressions for natural modes. It is proposed to use the advantages of this method to study the problems of dynamic stability and flutter of an orthotropic composite plate in a supersonic gas flow. Using the linear approximation of piston theory, solution of the problem is investigated according to the Galerkin method on the basis of the eigenforms of a composite plate in vacuum. According to this approach the boundary value problem is reduced to a homogeneous infinite linear algebraic system of equations with coefficients are depending from physical-mechanical and geometrical parameters of the problem. The frequency parameter is included in the system linearly, that allows us to reduce eigenproblem for infinite system to the problem of determining the eigenvalues and vectors of a matrix. The convergence of the Galerkin method depending on the number of basis functions is studied numerically. It is shown that the first 16 eigenforms provide the good convergence of the method. Examples of numerical implementation are given, obtained solution allow us to study the dependence of the critical velocity from the properties of the material and geometry of the combined plate.","PeriodicalId":38176,"journal":{"name":"PNRPU Mechanics Bulletin","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42642029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
ON THE RECONSTRUCTION OF PRESTRESS FIELDS IN A HOLLOW CYLINDER 关于空心圆柱体预应力场的重建
PNRPU Mechanics Bulletin Pub Date : 2023-12-15 DOI: 10.15593/perm.mech/2023.1.08
R. Nedin, V. Yurov
{"title":"ON THE RECONSTRUCTION OF PRESTRESS FIELDS IN A HOLLOW CYLINDER","authors":"R. Nedin, V. Yurov","doi":"10.15593/perm.mech/2023.1.08","DOIUrl":"https://doi.org/10.15593/perm.mech/2023.1.08","url":null,"abstract":"The present research is devoted to the development of the theoretical foundations of nondestructive acoustic method for identifying inhomogeneous prestress fields in a hollow cylinder, depending on the probing loading type. A linearized model of steady oscillations of an elastic body in the presence of an inhomogeneous prestress field of arbitrary nature is considered in the standard and weak formulations. On the basis of this model, we formulate a problem for a cantilever-clamped prestressed hollow cylinder that performs steady axisymmetric vibrations under three types of probing loading. A corresponding weak formulation of the problem in the cylindrical coordinate system is presented, in which six independent components of the prestress tensor are taken into account. At that, a case of prestress fields obtained by applying some initial mechanical external static load is considered. In the presence and absence of prestresses of various types, amplitude-frequency dependences are analyzed, and resonant and natural frequencies are found in a wide frequency range. Numerical calculations were carried out using the FEM on a non-uniform grid; mesh refinement is carried out in the vicinity of the boundary points, where the type of boundary conditions changes. Based on the numerical solution of an auxiliary set of direct problems, seven types of prestress fields are constructed, differing in the types of initial loading, most often encountered in practice. To assess the possibility of implementing the procedure for reconstructing prestresses of each of the considered types, a sensitivity analysis was additionally performed, which showed that for some prestress types there are frequencies and types of probing loading for which the presence of prestress is practically not manifested. The sensitivity analysis performed made it possible to implement the optimal method of probing loading when solving the inverse coefficient problem. The statement of the new inverse problem on the restoration of arbitrary inhomogeneous prestress fields in the considered finite hollow cylinder is formulated. When restoring the prestress of a given structure, the inverse problem is reduced to finding a set of parameters from an ill-conditioned algebraic system, which was studied with the help of the A.N. Tikhonov regularization method. Additional data for solving the inverse problem was obtained on the basis of probing both via a single load and via combined probing modes. It has been found that it is most effective to use a combined loading mode and use a sufficiently wide frequency range when selecting sounding frequencies. The results of computational experiments on the reconstruction of six components of the prestress tensor are presented and analyzed, and recommendations are proposed for choosing the optimal modes of acoustic sounding.","PeriodicalId":38176,"journal":{"name":"PNRPU Mechanics Bulletin","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67222191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
PROGRAMMABLE BEHAVIOR OF THE METAMATERIAL BY KINDS OF UNIT CELLS CONNECTION 可编程的超材料的行为由各种单元细胞连接
PNRPU Mechanics Bulletin Pub Date : 2023-12-15 DOI: 10.15593/perm.mech/2023.1.03
Smolin I.Yu., Programmable, Л . Р . Ахметшин, И . Ю . Смолин, Igor S. Yurievich, L. Akhmetshin, I.Yu. Smolin, ©. Pnrpu
{"title":"PROGRAMMABLE BEHAVIOR OF THE METAMATERIAL BY KINDS OF UNIT CELLS CONNECTION","authors":"Smolin I.Yu., Programmable, Л . Р . Ахметшин, И . Ю . Смолин, Igor S. Yurievich, L. Akhmetshin, I.Yu. Smolin, ©. Pnrpu","doi":"10.15593/perm.mech/2023.1.03","DOIUrl":"https://doi.org/10.15593/perm.mech/2023.1.03","url":null,"abstract":"The paper is devoted to the numerical analysis of uniaxial loading of a sample of the mechanical metamaterial. The structure of the mechanical metamaterial is constructed of a ring and four ligaments, which make up a tetrachiral structure. The peculiarity of such a structure consists in torsion of the sample under the force load. Two methods of connecting cells in the metamaterial are considered: \"adjoining\" and \"overlapping\". The \"adjoining\" method of joining cells increases the thickness of the internal structure of the sample, which allows us to consider it as a topological defect of the metamaterial. The \"overlapping\" method saves the base material from which the tetrachiral structure is constructed. Differences in the structure when constructing a three-dimensional sample result in a significant change in the characteristics of the sample. Numerical solution of the problem is performed in a three-dimensional formulation using the finite element method. The constitutive relation describing the behavior of the model corresponds to Hooke's law. Numerical simulation of uniaxial loading made it possible to obtain the results of mechanical response and to analyze the effective properties of metamaterials. A topological defect in the form of a thickening of the internal structure elements led to a difference in the linear dimensions of the two samples. The increased thickness of the unit cell connection elements resulted in a decrease in the effective density of the metamaterial sample. The same sample showed a triple increase in the value of the elastic modulus. The greater ability to resist deformation resulted in a reduced twist effect compared to the sample whose cells were joined by the \"overlapping\" method. The results obtained will make it possible to program the mechanical behavior and properties of the metamaterial sample.","PeriodicalId":38176,"journal":{"name":"PNRPU Mechanics Bulletin","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45626395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
SIMULATION OF ELASTOPLASTIC FRACTURE OF A CENTER CRACKED PLATE 中心裂纹板弹塑性断裂模拟
PNRPU Mechanics Bulletin Pub Date : 2023-12-15 DOI: 10.15593/perm.mech/2023.1.02
Н . С . Астапов, В . Д . Кургузов, V. Kurguzov, N. S. Astapov, ©. Pnrpu
{"title":"SIMULATION OF ELASTOPLASTIC FRACTURE OF A CENTER CRACKED PLATE","authors":"Н . С . Астапов, В . Д . Кургузов, V. Kurguzov, N. S. Astapov, ©. Pnrpu","doi":"10.15593/perm.mech/2023.1.02","DOIUrl":"https://doi.org/10.15593/perm.mech/2023.1.02","url":null,"abstract":"The strength of a square plate with a central crack at normal separation was studied within the framework of the Neuber–Novozhilov approach using a modified Leonov–Panasyuk–Dugdale model using an additional parameter, the diameter of the plasticity zone (width of the pre-fracture zone). As a model of a deformable solid body, a model of an ideal elastic-plastic material with a limiting relative elongation was chosen. This class of materials includes, for example, low-alloy steels used in structures operating at temperatures below the cold brittleness threshold. In the presence of a singular feature in the stress field in the vicinity of the crack tip, it is proposed to use a two-parameter discrete integral strength criterion. The deformation fracture criterion is formulated at the tip of a real crack, and the force criterion for normal stresses, taking into account averaging, is formulated at the tip of a model crack. The lengths of real and model cracks differ by the length of the pre-fracture zone. The constitutive equations of the analytical model are analyzed in detail depending on the characteristic linear dimension of the material structure. Simple formulas suitable for verification calculations for the critical breaking load and the length of the pre-fracture zone are obtained. Numerical modeling of the propagation of plasticity zones in square plates under quasi-static loading has been performed. In the numerical model, the updated Lagrangian formulation of the equations of mechanics of a deformable solid body is used, which is most preferable for modeling the deformation of bodies made of an elastic-plastic material at large deformation. The plastic zone in the vicinity of the crack tip is obtained by the finite element method. The results of analytical and numerical prediction of plate fracture under plane deformation are compared. It is shown that the results of numerical experiments are in good agreement with the results of calculations using the analytical model of fracture of materials with a structure under normal separation. Diagrams of quasi-brittle and quasi-ductile fracture of a structured plate are constructed.","PeriodicalId":38176,"journal":{"name":"PNRPU Mechanics Bulletin","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47111968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
MODELING OF 3D-PRINTING PROCESSES FOR COMPOSITE TOOLING AND TRANSFER MOLDING OF GRID STRUCTURES 复合材料模具三维打印工艺建模及网格结构的传递成型
PNRPU Mechanics Bulletin Pub Date : 2023-12-15 DOI: 10.15593/perm.mech/2023.1.15
Л . П . Шабалин, Е . А . Пузырецкий, Валентин Илдарович Халиулин, Владимир Владимирович Батраков, L. P. Shabalin, E. A. Puzyretskiy, V. Khaliulin, V. V. Batrakov, ©. Pnrpu
{"title":"MODELING OF 3D-PRINTING PROCESSES FOR COMPOSITE TOOLING AND TRANSFER MOLDING OF GRID STRUCTURES","authors":"Л . П . Шабалин, Е . А . Пузырецкий, Валентин Илдарович Халиулин, Владимир Владимирович Батраков, L. P. Shabalin, E. A. Puzyretskiy, V. Khaliulin, V. V. Batrakov, ©. Pnrpu","doi":"10.15593/perm.mech/2023.1.15","DOIUrl":"https://doi.org/10.15593/perm.mech/2023.1.15","url":null,"abstract":"The paper discusses the method of obtaining a digital passport of the material and the development of a digital twin of the product at various stages of its manufacture. The object of research is a conical mesh structure. The subject of research is the processes occurring in the product at the manufacturing stages. The following main stages of creating a mesh structure were considered in the work: 3D printing of a workpiece tooling, laying out a carbon unidirectional material, heating and impregnation of the preform with a binder, polymerization of the binder, and warpage of the product geometry. An algorithm for determining the properties of materials and their calibration using modern software and hardware and universal equipment was described. Modeling of the tooling 3D printing process was carried out in the Ansys software package. Step-by-step technological modeling of the transfer molding process was carried out using the ESI PAM-COMPOSITE software package. The result of the simulation is the optimal technological manufacturing parameters and the geometry of the shaping tooling with anticipation of warping.","PeriodicalId":38176,"journal":{"name":"PNRPU Mechanics Bulletin","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47828060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
IDENTIFICATION OF DEFECTS IN A COATING WEDGE BASED ON ULTRASONIC NON-DESTRUCTIVE TESTING METHODS AND CONVOLUTIONAL NEURAL NETWORKS 基于超声无损检测和卷积神经网络的涂层楔板缺陷识别
PNRPU Mechanics Bulletin Pub Date : 2023-12-15 DOI: 10.15593/perm.mech/2023.1.11
A. Soloviev, B. Sobol, P. Vasiliev, A. V. Senichev, A. Novikova
{"title":"IDENTIFICATION OF DEFECTS IN A COATING WEDGE BASED ON ULTRASONIC NON-DESTRUCTIVE TESTING METHODS AND CONVOLUTIONAL NEURAL NETWORKS","authors":"A. Soloviev, B. Sobol, P. Vasiliev, A. V. Senichev, A. Novikova","doi":"10.15593/perm.mech/2023.1.11","DOIUrl":"https://doi.org/10.15593/perm.mech/2023.1.11","url":null,"abstract":"The paper deals with the identification of a crack-like defect in a coated wedge based on ultrasonic nondestructive testing. The authors propose an approach of defect identification followed by determination of its geometrical parameters. The approach is based on a shadowed ultrasonic nondestructive testing method combined with deep machine learning technologies. A wedge-shaped area is inspected for the presence of an internal defect. On one edge of the wedge there is a source of ultrasonic vibrations, on the opposite edge there is a receiver. Passing through the coating and body of the wedge, part of the signal is reflected from inhomogeneities and defects that may be present in it. The signal reaching the opposite edge of the wedge is read by the receiver. The received data is processed by a neural network model, which predicts the presence or absence of an internal defect and, if present, determines geometric parameters such as size and position. A finite element model of ultrasonic wave propagation inside the wedge is constructed. Special damping layers are used, due to which the influence of parasitic signal reflections and its further propagation into the wedge body is significantly reduced. Based on the built model, the shadow method of ultrasonic scanning is implemented. This method implies that on one side of the wedge are installed excitation devices, and on the opposite side – receiving devices. Several numerical experiments for various combinations of geometric parameters of the wedge and the defect have been performed using a distributed computing system. Based on the obtained data, a neural network model was built and trained, capable of identifying the defect and determining its characteristics. The input of the model is spectrograms of the readout signal, and the output is values characterizing the defect.","PeriodicalId":38176,"journal":{"name":"PNRPU Mechanics Bulletin","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41631363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
NUMERICAL SIMULATION OF GAS-DYNAMIC AND STRENGTH CHARACTERISTICS OF A FAN FOR THE EXPERIMENTAL TEST RIG FOR INVESTIGATION OF ICE BREAKDOWN ON ROTATING WORKING BLADES 旋转工作叶片破冰实验试验台风机气动力及强度特性数值模拟
PNRPU Mechanics Bulletin Pub Date : 2023-12-15 DOI: 10.15593/perm.mech/2023.1.13
S. Kalyulin, N. A. Kalyulin, V. Modorskii, N. V. Vladimirov
{"title":"NUMERICAL SIMULATION OF GAS-DYNAMIC AND STRENGTH CHARACTERISTICS OF A FAN FOR THE EXPERIMENTAL TEST RIG FOR INVESTIGATION OF ICE BREAKDOWN ON ROTATING WORKING BLADES","authors":"S. Kalyulin, N. A. Kalyulin, V. Modorskii, N. V. Vladimirov","doi":"10.15593/perm.mech/2023.1.13","DOIUrl":"https://doi.org/10.15593/perm.mech/2023.1.13","url":null,"abstract":"The paper is devoted to modern experimental and computational studies analysis on the point of asymmetric destruction of ice on the surfaces of the working blades of gas-turbine engine blades. A schematic diagram of an experimental setup has been developed, which consists of the following main elements: a wind tunnel, a cold chamber, a model fan, an electric motor, and a high-speed video camera. The experimental setup makes it possible to carry out laboratory studies of the ice formation and destruction processes. The choice of the experimental test rig parameters was made to allow assessing the icing of the blades of a rotating fan, which reproduces the processes occurring on gas turbine engines. Based on the results of three-dimensional gas-dynamic and strength calculations, the design and basic geometrical parameters of the flow path and the dummy fan were determined. The dependences of compression ratio Pk and the power consumption of a model fan Wcons on the value of the mass air flow Gair for a different number of rotor blades are presented. The choice of materials for the disk hub and blades of a dummy fan which experience tensile and bending loads at high rotation speeds up to 12.000 rpm was made, that satisfies the conditions of static and dynamic strength, also the allowable safety factors were evaluated, and pressure characteristics were obtained.","PeriodicalId":38176,"journal":{"name":"PNRPU Mechanics Bulletin","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67222232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
APPLICABILITY INDICATORS FOR THE NONLINEAR MAXWELL-TYPE ELASTO-VISCOPLASTIC MODEL WITH POWER MATERIAL FUNCTIONS AND TECHNIQUES TO CALIBRATE THEM 非线性麦克斯韦型弹粘塑性模型的适用性指标及其标定技术
PNRPU Mechanics Bulletin Pub Date : 2023-12-15 DOI: 10.15593/perm.mech/2023.1.14
А. Khokhlov
{"title":"APPLICABILITY INDICATORS FOR THE NONLINEAR MAXWELL-TYPE ELASTO-VISCOPLASTIC MODEL WITH POWER MATERIAL FUNCTIONS AND TECHNIQUES TO CALIBRATE THEM","authors":"А. Khokhlov","doi":"10.15593/perm.mech/2023.1.14","DOIUrl":"https://doi.org/10.15593/perm.mech/2023.1.14","url":null,"abstract":"A physically non-linear Maxwell-type constitutive relation with two material functions for nonaging elasto-viscoplastic materials is studied analytically in order to examine the set of basic rheological phenomena that it simulates, to enclose its application field, to obtain necessary phenomenological restrictions which should be imposed on its material functions and to develop identification and validation techniques. Characteristic features of loading-unloading-recovery curves family produced by the model with two power material functions (with four parameters) under loading and unloading at constant stress rates and subsequent rest are analyzed in uni-axial case and compared to general properties of stress-strain-recovery curves produced by the constitutive relation with two arbitrary (increasing) material functions (theorems 1 and 2). Their dependences on loading rate, maximal stress and material functions exponents are examined. Power functions are the most popular in creep models, elastoviscoplasticity, polymer rheology, hydrodinamics of non-newtonian fluids and simulation of superplastic flow. The analysis reveals several specific properties of theoretic loading-unloading-recovery curves produced by power model with four parameters that can be employed as the model applicability indicators which are convenient for check using test data of a material. They should be checked in addition to general applicability indicators for the Maxwell-type constitutive relation with two arbitrary material functions. A number of effective calibration procedures for the model in the class of power material functions are developed. They are more rapid and effective than general identification techniques for two arbitrary material functions developed previously. The first procedure employs a pair of stress-strain curves at different stress rates, the second one is based on a pair of loadingunloading- recovery curves with various maximal stress values and loading rates and the third one needs only one loading-unloading-recovery curve. The explicit expressions are derived for four material parameters via test data. They enable separate and direct evaluation of the material parameters without error accumulation. Identification techniques versions are considered and their advantages and shortcomings are discussed. The ways to minimize the error using additional tests are proposed.","PeriodicalId":38176,"journal":{"name":"PNRPU Mechanics Bulletin","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67222244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
PLANE PROBLEMS ABOUT THE ACTION OF OSCILLATING LOAD ON THE BOUNDARY OF AN ELASTIC ISOTROPIC LAYER IN THE PRESENCE OF SURFACE STRESSES 存在表面应力时弹性各向同性层边界上振荡载荷作用的平面问题
PNRPU Mechanics Bulletin Pub Date : 2023-12-15 DOI: 10.15593/perm.mech/2023.1.05
Т . И . Калинина, А . В . Наседкин, О Статье Аннотация, Tamara I. Kalinina, Т. .. Kalinina, A. Nasedkin, ©. Pnrpu
{"title":"PLANE PROBLEMS ABOUT THE ACTION OF OSCILLATING LOAD ON THE BOUNDARY OF AN ELASTIC ISOTROPIC LAYER IN THE PRESENCE OF SURFACE STRESSES","authors":"Т . И . Калинина, А . В . Наседкин, О Статье Аннотация, Tamara I. Kalinina, Т. .. Kalinina, A. Nasedkin, ©. Pnrpu","doi":"10.15593/perm.mech/2023.1.05","DOIUrl":"https://doi.org/10.15593/perm.mech/2023.1.05","url":null,"abstract":"In this paper, symmetric and antisymmetric plane problems about the action of oscillating load on the boundary of an elastic isotropic nanothin layer are considered. The nanoscale layer thickness is considered by introducing surface stresses in accordance with the Gurtin-Murdoch theory. According to this theory, it is assumed that, in addition to external loads, surface stresses act on the layer boundaries, which are described by Hooke's “surface” law. As a result, the properties of the elastic material of the layer with nanoscale thickness become different from the properties of the material of a regular-sized body, which is typical for nanomechanics problems. A standard technique was used for the solution of formulated problems, including the application of limiting absorption principle, the Fourier transform over infinitely extended coordinate and the theory of residues for finding the inverse Fourier transform. It is shown how it is possible to obtain solutions in the form of series in natural waves, in which the wave numbers are defined as the roots of the corresponding dispersion equations. For a specific example, dispersion relations were studied and graphs of the first dispersion curves were plotted. The behavior of barrier frequencies, changes in wave numbers and zones of existence of backward waves at different nanoscale layer thicknesses are analyzed. The results of the analysis showed that for an ultrathin layer, surface effects have a significant impact on the dispersion relations, and the trends in the dispersion curves can differ significantly for different modes and layer thicknesses.","PeriodicalId":38176,"journal":{"name":"PNRPU Mechanics Bulletin","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48849222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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