{"title":"Walking Robot’s Getting Out from an Emergency Situation on Its Back","authors":"Yu. F. Golubev, V. V. Koryanov, E. V. Melkumova","doi":"10.3103/S0027133025700207","DOIUrl":"10.3103/S0027133025700207","url":null,"abstract":"<p>A method of swinging of the six-legged robot to ensure its overturn from the upside-down position is proposed. As a support, we consider an inclined plane with a slight slope towards the flip, with a pit and optionally with a bump next to it. The support can be rotated sequentially around two different axes. It is shown that the overturn is possible with the help of cyclic movement of the group of legs if the body has an upper shell in the form of a truncated cylinder. The swinging is performed by the legs on the edge of the body opposite to the one through which the flip is to occur. An analytical study of the model problem was performed, along with a simulation of the full dynamics of the robot in contact with the support using the Universal Mechanism software package. Specifics of swinging due to the slope, the pit, and the bump are shown.</p>","PeriodicalId":710,"journal":{"name":"Moscow University Mechanics Bulletin","volume":"80 3","pages":"120 - 128"},"PeriodicalIF":0.7,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145110517","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}
{"title":"On the Effect of the Loading Cycle Shape on the Development of Brittle Fracture Process","authors":"E. B. Zavoichinskaya, V. V. Putilov","doi":"10.3103/S0027133025700190","DOIUrl":"10.3103/S0027133025700190","url":null,"abstract":"<p>The durability for a trapezoidal axial loading cycle can be estimated using a model of scale-structural fatigue for a sinusoidal shape. For materials with frequency-dependent fatigue properties, the evaluation of the rectangular cycle (except for the instantaneous impulses) by the sinusoidal cycle goes into a safety margin. At the zero load, the absence of a rectangular cycle, the maximum stress, on average, is 5<span>(%)</span> lower (the durability is 2.5 times less) at the same number of cycles than that for a sinusoidal cycle and the loading period. The results are confirmed by experimental data on high- and very high fatigue of metals and alloys.</p>","PeriodicalId":710,"journal":{"name":"Moscow University Mechanics Bulletin","volume":"80 3","pages":"110 - 119"},"PeriodicalIF":0.7,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145110518","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}
D. I. Merkulov, D. A. Pelevina, I. I. Merkulova, V. A. Turkov, V. A. Naletova
{"title":"Motion of a Body with Anisotropic Magnetizable Elastomer in a Magnetic Field of the Electromagnetic Coil Taking into Account the Interaction with the Inclined Plane","authors":"D. I. Merkulov, D. A. Pelevina, I. I. Merkulova, V. A. Turkov, V. A. Naletova","doi":"10.3103/S002713302570013X","DOIUrl":"10.3103/S002713302570013X","url":null,"abstract":"<p>In this paper the motion of a spherical body with anisotropic magnetizable elastomer under the action of the magnetic field of an electromagnetic coil is studied experimentally and theoretically when the motion of the body is limited from below by an inclined plane. The dependences of the current in the coil on the angle of inclination of the plane, which separate the region in which the body either is at rest, or moves along an inclined plane, or first moves along an inclined plane and then breaks away from it, or immediately breaks away from the inclined plane are constructed experimentally. Based on the previously proposed mathematical model, which takes into account the interaction of the body (rolling, sliding) with the inclined plane and does not take into account the deformation of the body and surface roughness, similar dependences are calculated. The qualitative difference between the experiment and the theory proposed earlier is shown: in the experiment the body on the horizontal surface begins to move when the current in the coil reaches a certain value, while according to the previously proposed theory, the body begins to move at arbitrarily small currents. An improvement of the previously proposed theory is carried out: the moment of support reaction associated with the roughness of surfaces and the presence of a certain area of contact between the body and the plane is taken into account. The new model is shown to better describe the experimental results.</p>","PeriodicalId":710,"journal":{"name":"Moscow University Mechanics Bulletin","volume":"80 2","pages":"73 - 80"},"PeriodicalIF":0.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145168081","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}
{"title":"Numerical Study of the Motion of Thin Plates in a Viscous Fluid at Small Reynolds Numbers","authors":"A. V. Zvyagin, A. A. Shamina, A. Yu. Shamin","doi":"10.3103/S0027133025700116","DOIUrl":"10.3103/S0027133025700116","url":null,"abstract":"<p>The paper considers the problems of motion of thin bodies in a viscous incompressible liquid. In the Stokes approximation, the equations of motion are linear. This assumption allows using the fundamental solutions to reduce the problem of motion of thin bodies of finite size to singular integral equations. A numerical method for solving the obtained integral equations for the three-dimensional motion of bodies int he form of a set of thin impermeable and permeable plates (not a direct boundary element method) is proposed. The solution to the problem in this method is obtained in the form of a finite series expansion according to the found basic functions. Using the fundamental solutions to the Stokes equations, the problem of three-dimensional motion of thin bodies in a viscous liquid is reduced to a system of singular integral equations. The program codes for solving the resulting system of singular integral equations are written. The program allows obtaining the velocity fields, stress components, vortex distribution, and forces and moments acting on the plates.</p>","PeriodicalId":710,"journal":{"name":"Moscow University Mechanics Bulletin","volume":"80 2","pages":"53 - 62"},"PeriodicalIF":0.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145168079","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}
{"title":"Simulation of Trajectory Parameters of Motion of an Object near the Pole Using Quasi-Geodetic Coordinates","authors":"S. P. Ablyasova","doi":"10.3103/S0027133025700165","DOIUrl":"10.3103/S0027133025700165","url":null,"abstract":"<p>The paper discusses the challenges of inertial navigation in polar regions, where it is impossible to determine the longitude and true heading at the poles. To overcome this difficulty, it is proposed to use quasi-coordinates and quasi-attitude angles, as well as relevant quasi-ECEF and quasi-geodetic coordinate systems. It is proved that the quasi-geodetic (quasi-geocentric) coordinates, quasi-attitude angles, velocity of an object and inertial sensors readings can be simulated by using quasi-coordinates instead of traditional ones.</p>","PeriodicalId":710,"journal":{"name":"Moscow University Mechanics Bulletin","volume":"80 2","pages":"94 - 98"},"PeriodicalIF":0.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145168082","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}
{"title":"Teaching Mechanics Courses to Mathematics Students","authors":"V. V. Kozlov, D. V. Georgievskii, A. V. Vlakhova","doi":"10.3103/S0027133025700177","DOIUrl":"10.3103/S0027133025700177","url":null,"abstract":"<p>Possible statements of mathematical problems arising from topics in special courses in mechanics are discussed.</p>","PeriodicalId":710,"journal":{"name":"Moscow University Mechanics Bulletin","volume":"80 2","pages":"99 - 102"},"PeriodicalIF":0.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145168078","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}
{"title":"Spectral Decompositions in Dynamic Linear Viscoelasticity Problems for Piecewise Homogeneous Bodies","authors":"S. G. Pshenichnov","doi":"10.3103/S0027133025700128","DOIUrl":"10.3103/S0027133025700128","url":null,"abstract":"<p>The nonstationary dynamic viscoelasticity problem for a piecewise homogeneous body is considered. It is known that, under certain conditions, the construction of a solution to such a problem can be reduced to finding the eigenvalues of the free oscillation problem. The properties of a spectral set are considered, and a method for searching for its elements if proposed. The theoretical considerations are used to study the unsteady dynamics of a piecewise homogeneous viscoelastic plane-parallel layer. For some specific parameters of this layer, the elements of the spectrum are found, and, then, the transition wave process is studied.</p>","PeriodicalId":710,"journal":{"name":"Moscow University Mechanics Bulletin","volume":"80 2","pages":"63 - 72"},"PeriodicalIF":0.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145168080","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}
{"title":"On the Possibility of Dissipative Stabilization of a Periodic Motion of a System with One Degree of Freedom","authors":"V. A. Zubenko, E. I. Kugushev, T. V. Shakhova","doi":"10.3103/S0027133025700153","DOIUrl":"10.3103/S0027133025700153","url":null,"abstract":"<p>A conservative system with one degree of freedom admitting a periodic motion is considered. The system is located on a translationally moving base. Linear viscous friction forces are added to the forces acting on the points of the system. We determine the law of motion of the base that allows preserving the periodic motion of the initial system relative to this base. The conditions when the periodic motion becomes Lyapunov asymptotically stable are obtained by using the Vazhevsky inequality.</p>","PeriodicalId":710,"journal":{"name":"Moscow University Mechanics Bulletin","volume":"80 2","pages":"89 - 93"},"PeriodicalIF":0.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145168083","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}
{"title":"Vector Properties of Elastoplastic Processes of Deformation along Plane Paths of Moderate Curvature","authors":"A. V. Muravlev, M. A. Stepina","doi":"10.3103/S0027133025700141","DOIUrl":"10.3103/S0027133025700141","url":null,"abstract":"<p>Various hypotheses proposed with the Il’yushin plasticity theory framework and expressed in terms of ODEs and multiple integrals are studied. One of the key aspects of this approach is a classification of constitutive equations by the complexity of loading for which a certain relation is suitable. Some relations of markedly different forms are proposed for a group of strain paths with moderate curvatures; this group is the most general kind of stress-strain relations in this classification. In the present paper the connections between those relations are discussed.</p>","PeriodicalId":710,"journal":{"name":"Moscow University Mechanics Bulletin","volume":"80 2","pages":"81 - 88"},"PeriodicalIF":0.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145168077","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}
{"title":"Il’yushin’s Particular Postulate and Nonlinear Relations for Anisotropic Bodies","authors":"A. A. Markin, M. Yu. Sokolova, D. V. Khristich","doi":"10.3103/S0027133025700086","DOIUrl":"10.3103/S0027133025700086","url":null,"abstract":"<p>A review of the works devoted to the theoretical study and experimental verification of one of the fundamental hypotheses of the theory of processes by A.A. Il’yushin, the particular postulate of isotropy, as well as the possibility of its generalization to initially anisotropic materials is fulfilled. A formulation of such a generalization is proposed using the concept of invariant subspaces of the symmetry group of an anisotropic material. As an example, within the framework of the proposed generalization, nonlinear constitutive relations for an elastic orthotropic material are constructed.</p>","PeriodicalId":710,"journal":{"name":"Moscow University Mechanics Bulletin","volume":"80 1","pages":"23 - 32"},"PeriodicalIF":0.7,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145161539","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}