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1
Alouges, François, Yacine Chitour y Ruixing Long. "A Motion-Planning Algorithm for the Rolling-Body Problem". IEEE Transactions on Robotics 26, n.º 5 (octubre de 2010): 827–36. http://dx.doi.org/10.1109/tro.2010.2053733.
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Chitour, Y., A. Marigo y B. Piccoli. "Quantization of the rolling-body problem with applications to motion planning". Systems & Control Letters 54, n.º 10 (octubre de 2005): 999–1013. http://dx.doi.org/10.1016/j.sysconle.2005.02.012.
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Miftakhova, Almira, Yang-Yuan Chen y Jeng-Haur Horng. "Effect of rolling on the friction coefficient in three-body contact". Advances in Mechanical Engineering 11, n.º 8 (agosto de 2019): 168781401987230. http://dx.doi.org/10.1177/1687814019872303.
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The contact problem of system of particles rolling over a viscoelastic layer bonded to the rigid half-space was considered. Particles have a spherical shape and their radiuses are distributed along Gauss. Earlier, the friction coefficient was obtained for the particles between surfaces in the relative movement of the surfaces using the three-body interaction method. In this study, the contact area was calculated for a system of particles rolling over the viscoelastic layer bonded to the half-space. Using the three-body interaction approach, the friction coefficient was calculated, taking into account the rolling of particles. The results demonstrate that the coefficient of friction, calculated using the three-body model, decreases when the rolling of particles is taken into account.
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Kennedy, Kevin F. "An Approximate Three-Dimensional Metal Flow Analysis for Shape Rolling". Journal of Engineering for Industry 110, n.º 3 (1 de agosto de 1988): 223–31. http://dx.doi.org/10.1115/1.3187873.
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An approximate three-dimensional metal flow analysis for shape rolling is developed. The analysis, which is presently applicable to rod rolling, is based on an upper-bound approach in which an iterative numerical procedure is used to minimize the energy dissipation rate to obtain kinematically admissible velocity field solutions of the rolling problem. Once the velocity field and the final shape of the plastically deforming body are known, then elementary stress analysis techniques are used to determine the force related aspects of the rolling problem. It is assumed that the rolled material is rigid perfectly plastic, and only the purely mechanical aspects of the metal deformation problem in rolling are considered assuming isothermal conditions. The analysis shows good agreement with elongation and roll separating force measurements in the hot rolling of mild carbon steel for a variety of workpiece and roll cross-section geometries commonly used in rod rolling.
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Kennedy, K. F. "A Method for Analyzing Spread, Elongation and Bulge in Flat Rolling". Journal of Engineering for Industry 109, n.º 3 (1 de agosto de 1987): 248–56. http://dx.doi.org/10.1115/1.3187126.
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A method for analyzing spread, elongation, and bulge in flat rolling is developed. The analysis is based on an upper-bound approach in which an iterative numerical procedure is used to minimize the energy dissipation rate for kinematically admissible velocity field solutions for the rolling problem. Once the velocity field and the final shape of the plastically deforming body are known, then elementary stress analysis techniques are used to determine the force related aspects of the rolling problem. It is assumed that the rolled material is rigid perfectly plastic, and only the purely mechanical aspects of the metal deformation problem in rolling are considered, assuming isothermal conditions. The analysis shows good agreement with spread, elongation, roll separating force, and roll torque measurements in the hot rolling of mild carbon steel. Discussion of the factors which lead to single-bulge or double-bulge deformation in flat rolling, and a suggested technique for estimating the interface friction conditions in rolling, the Flat Bar Test, are also included.
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Moghadasi, S. Reza. "Rolling of a body on a plane or a sphere: a geometric point of view". Bulletin of the Australian Mathematical Society 70, n.º 2 (octubre de 2004): 245–56. http://dx.doi.org/10.1017/s0004972700034468.
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A pair of bodies rolling on each other is an interesting example of nonholonomic systems in control theory. Here the controllability of rolling bodies is investigated with a global approach. By using simple geometric facts, this problem has been completely solved in the special case where one of them is a plane or a sphere.
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Chepchurov, Mihail, Alexander Sumskoy, Julia Zhigulina y Denis Podpryatov. "Distortion identification of the cylindrical part form of technological units". Automation and modeling in design and management 2022, n.º 4 (21 de diciembre de 2022): 29–36. http://dx.doi.org/10.30987/2658-6436-2022-4-29-36.
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The paper deals with the issues arising during the technological unit operation, in particular, the geometric characteristics control of large parts of the units. The main types of rolling the surface wear of cylindrical elements of various technological equipment are given (according to GOST 24642-81, GOST 18322-2016). The equipment wear patterns due to the operating conditions and the unit design, as well as differences in the part shape distortion with the roundness loss are highlighted. It is revealed that the uneven wear of the rolling surface of the technological cylindrical parts causes shape distortion. Considering this, the profile of a conditional round part in cross section relative to one centre is modelled. The appearance of ovality is accepted as the main defect of cylindrical parts. A calculation scheme is presented for constructing the distortion of the cylindrical body profile located on two round supports. An algorithm for computing the radii centre displacement is presented. Theoretical calculations and the algorithm are confirmed by a virtual kinematic model that displays rolling a non-circular body on two idlers. The method described in the paper for obtaining a visual kinematic model, based on an analytical description of rolling a non-circular body, is proposed to be used as a direct problem of searching for instantaneous centres of rotation. The kinematic model obtained by solving the direct problem can be applied for training a neural network that processes the measurement results of a real rolling body
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Sönmez, Murat. "A Study on the Combined Effect of Axle Friction and Rolling Resistance". International Journal of Mechanical Engineering Education 31, n.º 2 (abril de 2003): 101–7. http://dx.doi.org/10.7227/ijmee.31.2.2.
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Many textbooks on mechanics for engineering students and engineers consider the concepts of rolling resistance and axle friction separately, expecting readers to combine the given analysis for each of them in determining, for instance, the magnitude of the force needed to move a railroad car. However, this requires a thorough free-body diagram analysis and, since examples are not typically included in the textbooks, students may have difficulty solving such problems. This study represents the solution of the problem in terms of both the dry axle friction and the rolling resistance. It is also suggested as a good synthesis problem that may be considered in teaching the effect of dry friction to engineering students.
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Spector, A. A. y R. C. Batra. "Rolling/Sliding of a Vibrating Elastic Body on an Elastic Substrate". Journal of Tribology 118, n.º 1 (1 de enero de 1996): 147–52. http://dx.doi.org/10.1115/1.2837070.
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The rolling/sliding in the presence of friction of a vibrating elastic body on an elastic substrate is studied. It is shown that the longitudinal components of the velocity of the center of mass of the body and of the resultant frictional force are not affected by the vibration process. However, the normal vibration of the body influences the slip velocities and the distribution of frictional forces. For the problem of a harmonically oscillating long cylinder rolling/sliding on the flat surface of an elastic substrate, the time histories of the width of the contact zone and the length of adhesion subzone are computed. It is shown that the local frictional forces and slip velocities oscillate, and that the set of admissible values of the external frictional forces and moments providing the rolling/sliding regime is smaller under conditions of normal vibrations than that when the cylinder does not vibrate.
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Spector, A. y R. C. Batra. "On the Motion of an Elastic Body Rolling/Sliding on an Elastic Substrate". Journal of Tribology 117, n.º 2 (1 de abril de 1995): 308–14. http://dx.doi.org/10.1115/1.2831248.
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The three-dimensional evolutionary problem of rolling/sliding of a linear elastic body on a linear elastic substrate is studied. The inertial properties of the body regarded as rigid are accounted for. By employing an asymptotic analysis, it is shown that the process can be divided into two phases: transient and quasistationary. An expression for the frictional force as a function of the externally applied forces and moments, and inertial properties of the body is derived. For an ellipsoid rolling/sliding on a linear elastic substrate, numerical results for the frictional force distribution, slip/adhesion subareas, and the evolution of the slip velocity are given.
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Goshima, T. y L. M. Keer. "Thermoelastic Contact Between a Rolling Rigid Indenter and a Damaged Elastic Body". Journal of Tribology 112, n.º 2 (1 de abril de 1990): 382–90. http://dx.doi.org/10.1115/1.2920268.
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The two-dimensional thermoelastic contact problem of a rolling, rigid cylinder on an elastic half space containing a surface-breaking crack is solved using complex variable techniques. The effects of heat generation and friction between the cylinder and half space and of friction and heat transfer on the faces of the crack are considered. The problem is reduced to a pair of singular integral equations which are solved numerically. Numerical results are obtained when the loading is a Hertzian distributed heat input. By consideration of combinations of parameters, stress intensity factors for which the crack is likely to grow are shown.
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Tang, Liqiong, Donald Bailey y Matthieu Jones. "Rolling Prevention Mechanism for Underground Pipe Erosion Inspection Robot with a Real Time Vision System". International Journal of Intelligent Mechatronics and Robotics 3, n.º 3 (julio de 2013): 60–76. http://dx.doi.org/10.4018/ijimr.2013070105.
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Pipe inspection is one of the areas that have attracted high research interest for robot applications especially in oil and chemical industry and civil engineering. Robot body rolling while it travels within a pipe has been a problem for accurately collecting inspection data. Under certain circumstances where vision systems have to be employed, robot body rolling may cause vision inspection data to have little value as it is difficult to know where exactly the camera was looking at. This paper proposes an anti-rolling mechanism to hold consistent camera orientation. By changing the position angle of the robot legs, the mechanism is able to adjust the resistance to rolling within a pipe, therefore preventing robot rolling happening. The design makes use of the friction force caused by the gravity force of the robot to prevent the robot body rolling. The design analysis quantifies the effect of pipe radius, robot weight, payload, and payload offset distance in robot rolling. A test model was built based on the design concept. The experimental results obtained from the test model match the predication of the computational analysis. A real time vision system has been developed using FPGA and the algorithm of the structured laser light stripe configuration in the context of pipe inspection. The real-time hardware implementation of the algorithms on the robot itself removes the need to transmit raw video data back to an operator.
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CHEN, MENG-CHENG y HUI-QIN YU. "THREE-DIMENSIONAL SURFACE CRACK ANALYSIS OF ELASTIC HALF-SPACE UNDER ROLLING CONTACT LOAD". International Journal of Computational Methods 06, n.º 02 (junio de 2009): 317–32. http://dx.doi.org/10.1142/s021987620900184x.
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In this work a three-dimensional planar crack on the surface of elastic half-space was analyzed under rolling contact load. The stresses interior to an elastic half-space body under rolling contact load and those produced by an infinitesimal displacement jump loop for the elastic half-space body were used to reduce the planar crack problem to the solution of a system of two-dimensional hypersingular integral equations with unknown displacement jump. The ideas of finite element discretization were employed to construct numerical solution schemes for solving the integral equations. An appropriate treatment of the associated hypersingular integral in the numerical solution to the integral equations was proposed in Hadamard's finite-part integral sense. The numerical results showed that the present procedure yields solutions with high accuracies. The stress intensity factors near the crack front edge under rolling contact load were indicated in graphical form with varying the crack shape, the radius of rolling contact zone and the friction coefficients, respectively. In addition, the influence of the lubricant infiltrating the crack surfaces on the crack propagation was also discussed in the paper.
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Avitzur, B., W. Gordon y S. Talbert. "Analysis of Strip Rolling by the Upper Bound Approach". Journal of Engineering for Industry 109, n.º 4 (1 de noviembre de 1987): 338–46. http://dx.doi.org/10.1115/1.3187137.
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The process of strip rolling is analyzed using the upper bound technique. Two triangular velocity fields, one with triangles in linear rigid body motion and the other with triangles in rotational rigid body motion, are developed. The total power is determined as a function of the four independent process parameters (relative thickness, reduction, friction and net front-back tension). The results of these two velocity fields are compared with the established solution from Avitzur’s velocity field of continuous deformation. Upon establishing the validity of the triangular velocity field as an approach to the strip rolling problem, recommendations are suggested on how this approach can be used to study the split end or alligatoring defect.
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WU, WENHUA, DEHUA CHEN, NING QIN, XIN PENG y XINWU TANG. "A NEW EFFICIENT CONTROL METHOD FOR BLENDED WING BODY". International Journal of Modern Physics: Conference Series 19 (enero de 2012): 396–405. http://dx.doi.org/10.1142/s2010194512008999.
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The blended wing body (BWB) is the hottest one of the aerodynamic shapes of next generation airliner because of its' high lift-drag ratio, but there are still some flaws that cut down its aerodynamical performance. One of the most harmful flaws is the low efficiency of elevator and direction rudder, this makes the BWB hard to be controlled. In this paper, we proposed a new control method to solve this problem by morphing wing—that is, to control the BWB only by changing its wing shape but without any rudder. The pitching moments, rolling moments and yawing moments are plotted versus the parameters section and the wing shape in figures and are discussed in the paper. The result shows that the morphing wing can control the moments of BWB more precisely and in wider range. The pitching moments, rolling moments and yawing moments increases or decreases linearly or almost linearly, with the value of the selected parameters. These results show that using morphing wing is an excellent aerodynamic control way for a BWB craft.
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Sari, O¨ T., G. G. Adams y S. Mu¨ftu¨. "Nano-Scale Effects in the Sliding and Rolling of a Cylinder on a Substrate". Journal of Applied Mechanics 72, n.º 5 (12 de agosto de 2005): 633–40. http://dx.doi.org/10.1115/1.1831291.
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The behavior of a nano-scale cylindrical body (e.g., a fiber), lying on a substrate and acted upon by a combination of normal and tangential forces, is the subject of this investigation. As the scale decreases to the nano level, adhesion becomes an important issue in this contact problem. Thus, this investigation treats the two-dimensional plane strain elastic deformation of both the cylinder and the substrate during a rolling/sliding motion, including the effect of adhesion using the Maugis model. For the initiation of sliding, the Mindlin approach is used, whereas for rolling, the Carter approach is utilized. Each case is modified for nano-scale effects by including the effect of adhesion on the contact area and by using the adhesion theory of friction for the friction stress. Analytical results are given for the normal and tangential loading problems, including the initiation of sliding and rolling in terms of dimensionless quantities representing adhesion, cylinder size, and applied forces.
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Sumtsov, Andriy, Anatoliy Falendysh, Nataliya Chyhyryk y Oleg Vasilenko. "Energy Saving for the Suburban Rolling Stock". International Journal of Engineering & Technology 7, n.º 4.3 (15 de septiembre de 2018): 361. http://dx.doi.org/10.14419/ijet.v7i4.3.19835.
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This article is concerned with the problem of energy savings and rise of comfortableness of railway rolling stock. Done analysis has shown the insufficient paying attention to the energy efficiency of suburban rolling stock. In particular, to the problem of heat comfort for passengers. For this purpose, a procedure was carried out for the thermal audit of electric trains, taking into account the prevailing array of required indicators. To determine the sites of local heat losses, there was done the thermal-imaging inspection of the electrical train ER2 series during which it was determined the local sites of heat losses and entry of cold air. Besides the passenger compartment, there were inspected the outer body liner and driver's cabin. As a result of inspection of driver's cabin, it was found the bad quality of a sealing layer for side small windows from one side. On the basis of inspection, the recommendations for elimination of found irregularities were developed.
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CHERNOUS, Dmitry A. y Alena V. KADNIANKA. "ASYMPTOTIC APPROACH TO SOLVING THE CONTACT PROBLEM FOR A ROLLING BODY WITH A THIN DEFORMABLE RIM". Mechanics of Machines, Mechanisms and Materials 1, n.º 62 (marzo de 2023): 79–87. http://dx.doi.org/10.46864/1995-0470-2023-1-62-79-87.
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On the basis of an asymptotic approach to solving the elasticity theory boundary value problem for a thin strip rigidly linked to a non-deformable base, the differential equations are derived for determining the normal and shear loads distributed on the strip face free from fastening. These equations are used to solve the contact problem for a rigid cylinder with a thin elastic rim with a non-deformable horizontal rough support surface. The cylinder loading by a vertical force is considered for a given cylinder center settling. The calculated diagrams of contact pressure and shear contact stresses are obtained. In contrast to the previously used methods, the developed technique makes it possible to take into account the presence of adhesion and slip zones in the contact area, as well as to use a mathematically strict solution of the constitutive equations for contact pressure and shear contact stress. The value of the vertical force acting on the rigid cylinder for a given cylinder center displacement is determined. The stress tensor intensity distribution in the rim is established. The results of the developed technique application are compared with the calculated estimates obtained on the basis of the exact solution of the boundary value problem for a strip of arbitrary thickness and within the method, involving the use of the Winkler base simplified model. The dependences of the results error for the developed method on the thickness and Poisson's ratio of the rim material are obtained. The paper describes the effect of the rim-support surface friction coefficient on the contact pressure, shear contact pressure, and the maximum intensity of the stress tensor in the rim. It is concluded that it is reasonable to use the developed technique at solving contact problems for rolling elements with a relatively thin elastic rim.
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Kuleshov, A. S. "First integrals in the problem of rolling a body of revolution over a rough plane". Doklady Physics 48, n.º 7 (julio de 2003): 385–87. http://dx.doi.org/10.1134/1.1598254.
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Tang, Hua Tao y Xin Yue Wu. "Study of Transfer Matrix of Rolling Bearing Including Squeeze Film Damper". Advanced Materials Research 490-495 (marzo de 2012): 618–22. http://dx.doi.org/10.4028/www.scientific.net/amr.490-495.618.
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The transfer matrix of rolling bearing including squeeze film damper (SFD) is studied, and the rotor – bearing system is modeled by transfer matrix method of multi-body system. It is proved by an example that the method, which provides a new idea to solve the problem of complex rotor – bearing system, is feasible and effective.
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Li, Li Fu y Ming Jun Yang. "Dynamic Bending Mathematical Model of Vehicle Adaptive Front-Lighting System Based on Rolling Characteristics". Applied Mechanics and Materials 644-650 (septiembre de 2014): 117–21. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.117.
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When the vehicle is turning, the vehicle body will tend to roll because of centrifugal force, which will lead to the change of headlamps' space location and the mismatch between light type and the regulation GB4599-2007. Directing at this problem, first the relationship among the rolling characteristics of vehicle, light distribution characteristics of AFS headlamps and dynamic light angle of AFS was analyzed in the article. Then a dynamic bending mathematical model of AFS based on rolling characteristics was proposed. Based on the three degrees of freedom of manipulation model, the interaction mechanism between the roll angle and light distribution characteristics of AFS was analyzed, and the dynamic bending mathematical model of AFS based on rolling characteristics which can amend the illumination direction of AFS was built afterwards. After analysis in Matlab and Tracepro, the results show that the dynamic AFS headlamp angle determines the maximum of 1.75° angular increment in the xy plane and 2.25° in the yz plane, and solves the problem of the mismatch between light type and regulation GB4599-2007.
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Gorr, G. V. "Cinematic Interpretation of Motion a Rigid Body in a new Solution of Grioli Equations". Прикладная математика и механика 87, n.º 6 (1 de noviembre de 2023): 901–14. http://dx.doi.org/10.31857/s0032823523060048.
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In the article, a new solution is obtained for the problem on motion of a rigid body, having a fixed point, under the action of potential and gyroscopic forces. With use of the modified Poisson method, proposed by the author, it is shown that the motion of the body in this solution can be presented by rolling without sliding of the ellipsoid of inertia of the body along a plane fixed in the immovable space. This result may be considered as an analysis of Poisson result on interpretation of motion a rigid body in Euler solution.
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Bronars, Antonia y Oliver M. O'Reilly. "Gliding motions of a rigid body: the curious dynamics of Littlewood's rolling hoop". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 475, n.º 2231 (noviembre de 2019): 20190440. http://dx.doi.org/10.1098/rspa.2019.0440.
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The celebrated mathematician John E. Littlewood noted that a hoop with an attached mass rolling on a ground plane may exhibit self-induced jumping. Subsequent works showed that his analysis was flawed and revealed paradoxical behaviour that can be resolved by incorporating the inertia of the hoop. A comprehensive analysis of this problem is presented in this paper. The analysis illuminates the regularity induced in the model of the hoop when its mass moment of inertia is incorporated, shows that the paradoxical motions of the hoop are consistent with the principles of mechanics and demonstrates the simplest example in the dynamics of rigid bodies that exhibits self-induced jumping.
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Shen, Guangxian, Xuedao Shu y Ming Li. "Three-Dimensional Contact Boundary Element Method for Roller Bearing". Journal of Applied Mechanics 72, n.º 6 (14 de junio de 2005): 962–65. http://dx.doi.org/10.1115/1.2041662.
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The analysis of the forces and the rigidity of roller bearings is a multi-body contact problem, so it cannot be solved by contact boundary element method (BEM) for two elastic bodies. Based on the three-dimensional elastic contact BEM, according to the character of roller bearing, the new solution given in this paper replaces the roller body with a plate element and traction subelement. Linear elements are used in non-contact areas and a quadratic element is used in the contact area. The load distribution among the roller bodies and the load status in the inner rolling body can be extracted.
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S.O., Gladkov y Bogdanova S.B. "TO THE THEORY OF n-DIMENSIONAL BRACHISTOCHRONE". Vestnik Tomskogo gosudarstvennogo universiteta. Matematika i mekhanika, n.º 68 (2020): 53–60. http://dx.doi.org/10.17223/19988621/68/5.
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In this paper, a solution to the problem of the motion of a brachistochrone in the ndimensional Euclidean space is firstly presented. The very first formulation of the problem in a two-dimensional case was proposed by J. Bernoulli in 1696. It represented an analytical description of the trajectory for the fastest rolling down under gravitational force only. Thereafter, a number of problems devoted to a brachistochrone were considered with account for gravitational forces, dry and viscous drag forces, and a possible variation in the mass of a moving body. Analytical solution to the formulated problem is presented in details by an example of the body moving along a brachistochrone in three-dimensional Cartesian coordinates. The obtained parametric solution is confirmed by a graphical interpretation of the calculated result. The formulated problem is solved for an ideal case when drag forces are neglected. If dry and viscous friction forces are taken into account, the plane shape of the brachistochrone remains the same,while the analysis of the solution becomes more complicated. When, for example, a side air flow is taken into account, the plane curve is replaced by a three-dimensional brachistochrone.
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Al-Bender, Farid y Kris De Moerlooze. "A Model of the Transient Behavior of Tractive Rolling Contacts". Advances in Tribology 2008 (2008): 1–17. http://dx.doi.org/10.1155/2008/214894.
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When an elastic body of revolution rolls tractively over another, the period from commencement of rolling until gross rolling ensues is termed the prerolling regime. The resultant tractions in this regime are characterized by rate-independent hysteresis behavior with nonlocal memory in function of the traversed displacement. This paper is dedicated to the theoretical characterization of traction during prerolling. Firstly, a theory is developed to calculate the traction field during prerolling in function of the instantaneous rolling displacement, the imposed longitudinal, lateral and spin creepages, and the elastic contact parameters. Secondly, the theory is implemented in a numerical scheme to calculate the resulting traction forces and moments on the tractive rolling of a ball. Thirdly, the basic hysteresis characteristics are systematically established by means of influence-parameters simulations using dimensionless forms of the problem parameters. The results obtained are consistent with the limiting cases available in literature and they confirm experimental prerolling hysteresis observations. Furthermore, in a second paper, this theory is validated experimentally for the case of V-grooved track.
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Kilin, Alexander A. y Elena N. Pivovarova. "Stability of Vertical Rotations of an Axisymmetric Ellipsoid on a Vibrating Plane". Mathematics 11, n.º 18 (17 de septiembre de 2023): 3948. http://dx.doi.org/10.3390/math11183948.
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In this paper, we address the problem of an ellipsoid with axisymmetric mass distribution rolling on a horizontal absolutely rough plane under the assumption that the supporting plane performs periodic vertical oscillations. In the general case, the problem reduces to a system with one and a half degrees of freedom. In this paper, instead of considering exact equations, we use a vibrational potential that describes approximately the dynamics of a rigid body on a vibrating plane. Since the vibrational potential is invariant under rotation about the vertical, the resulting problem with the additional potential is integrable. For this problem, we analyze the influence of vibrations on the linear stability of vertical rotations of the ellipsoid.
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Voron, O. A. "Methodology of Research on the Demand for Development of Transport Infrastructure and Rolling Stock for Perishable Goods Transportation". World of Transport and Transportation 19, n.º 3 (2 de diciembre de 2021): 6–15. http://dx.doi.org/10.30932/1992-3252-2021-19-3-1.
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In the context of globalisation of economic relationships, intensification of transportation and technological solutions, the methodology of research and development of transport infrastructure requires improvement and adaptation to dynamically changing conditions of the transportation market.The objective of the work is to formalise and to develop a methodology for studying transport infrastructure, including specialised isothermal rolling stock. The initial data on cargo turnover were processed by the methods of mathematical statistics, and the technical parameters of innovative isothermal rolling stock were substantiated using the methods of T. Saaty analytic hierarchy process, expert assessment, and update engineering design process.The article provides an analysis of the cargo turnover of perishable goods transported by railway refrigerated transport in Russia in terms of volumes, types of rolling stock, and origin. The main origin-destination cargo flows are presented by types of transportation (domestic, transit, export, import transport operations). It has been determined that key factors in development of isothermal rolling stock for transportation of perishable goods in the transport system of the country refer to transportation of meat, fish, beer, soft drinks, juices in the segment of domestic transportation. The analysis shows that there are no structural and quantitative shifts in terms of types of transportation and types of cargo.The strategy for development of vehicles for transportation of perishable goods and the methodology are presented in a block diagram, in sections: «statement of the research problem», «decision-making stages», «decision implementation methods and algorithms». It is shown that the problem includes not only development of stationary railway infrastructure and of stages in development of isothermal rolling stock, but also the need to solve organisational, technical, technological, regulatory, and legal problems, as well as tariff regulation.The issues of methodology for designing an innovative isothermal rolling stock are considered referring to possible prospects for its development and areas of operation, as well as to a set of engineering and technological solutions. The study of linear dimensions and useful section of the loading space of various types of isothermal bodies shows the advantage of wagons and swap bodies in comparison with large-capacity refrigerated containers.It is proposed to design a prototype of innovative isothermal rolling stock on the basis of a universal isothermal swap body, configured with various types of refrigerating equipment with specified technical parameters that best meet the requirements of the modern transportation market. The areas of possible use of various types of isothermal rolling stock are analysed considering long-term forecasts for development of agricultural, fishing and processing industries.
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Glukhikh, Yu D. y V. N. Tkhai. "Parametric resonance in the problem of a heavy rigid body rolling along a straight line on a plane". Journal of Applied Mathematics and Mechanics 66, n.º 6 (enero de 2002): 971–84. http://dx.doi.org/10.1016/s0021-8928(02)00139-9.
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Kukielka, Krzysztof, Leon Kukielka, Łukasz Bohdal, Agnieszka Kułakowska, Leszek Malag y Radoslaw Patyk. "3D Numerical Analysis the State of Elastic/Visco-Plastic Strain in the External Round Thread Rolled on Cold". Applied Mechanics and Materials 474 (enero de 2014): 436–41. http://dx.doi.org/10.4028/www.scientific.net/amm.474.436.
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This work describes the thread rolling as a real object and its physical and mathematical modelling. An incremental modelling and numerical solution of the contact problem between movable elastic or rigid tool and elastic/visco-plastic bodies developed in [ is adopted to the numerical simulation of thread rolling process for the case of rigid tool (threading head) and elastic/visco-plastic body (pipe or bar). An update Lagrangian formulation was used to describe nonlinear phenomena on a typical incremental step. For solution of discrete equations of motions and deformations of the object the explicit integration method was applied. The algorithm and application of 3D numerical analysis in ANSYS program were elaborated. This algorithm let for determination of influence of friction coefficient, initial yield stress and plastic hardening modulus. This factors influence will be carried out with 5 levels rotary experiment plan, which let for elaboration of regression equation to describe this relationship. Exemplary results of 3D numerical analysis of displacement and strain in thread for different conditions of rolling process are presented.
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Horobets, Yevhen. "Estimation of the error of the simplified algorithm of processing of functions of deflations of deformed frames of bodies of rolling stock". Technology audit and production reserves 4, n.º 1(60) (30 de junio de 2021): 20–24. http://dx.doi.org/10.15587/2706-5448.2021.237296.
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The study is aimed at assessing the size of the error that arises when processing the results of examining the geometric characteristics of the bearing structures of rolling stock units using an algorithm without using trigonometric functions. The object of the research is a method of simplified alignment of the deflection function of body frame beams to the horizontal plane. One of the biggest problem areas is the lack of understanding by some customers of the work of the possibility of using this algorithm due to the lack of information about the errors that arise in the simplified calculation. The study was carried out by comparing the results of processing the initial data by two methods, obtained during the work on the inspection of the state of the supporting structures of the unit of the shunting diesel locomotive TGM6. One method, the algorithm of which is the subject of this study, assumes that no complex calculations are used during data processing. The second method involves the use of an algorithm for aligning the deflection functions of the body frame beams of a rolling stock unit of railways in the horizontal plane, taking into account all trigonometry tools, which will exclude the accompanying calculation errors of the simplified method. After processing the initial data, two sets of results were obtained – with the desired calculation error and without. Comparison of these datasets yielded an error value for frame tilt of 5.7. For clarity, the size of the error was compared with the expanded uncertainty values of the main sources of uncertainty in the methodology for examining the bearing structures of rolling stock. On the basis of the analysis of two methods of leveling the inclination to the horizontal plane of the deformed rolling stock body frame, the expediency of such an approach has been proved. The results obtained make it possible to reasonably use the Simplified approach to processing the data obtained during the survey of the geometric characteristics of the rolling stock. If necessary, the developed mathematical model can be used to improve the accuracy of calculating the uncertainty of measurements of geometric characteristics, as well as for use in the study of modification of existing or development of new measurement techniques
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Song, P., P. Kraus, V. Kumar y P. Dupont. "Analysis of Rigid-Body Dynamic Models for Simulation of Systems With Frictional Contacts". Journal of Applied Mechanics 68, n.º 1 (16 de junio de 2000): 118–28. http://dx.doi.org/10.1115/1.1331060.
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The use of Coulomb’s friction law with the principles of classical rigid-body dynamics introduces mathematical inconsistencies. Specifically, the forward dynamics problem can have no solutions or multiple solutions. In these situations, compliant contact models, while increasing the dimensionality of the state vector, can resolve these problems. The simplicity and efficiency of rigid-body models, however, provide strong motivation for their use during those portions of a simulation when the rigid-body solution is unique and stable. In this paper, we use singular perturbation analysis in conjunction with linear complementarity theory to establish conditions under which the solution predicted by the rigid-body dynamic model is stable. We employ a general model of contact compliance to derive stability criteria for planar mechanical systems. In particular, we show that for cases with one sliding contact, there is always at most one stable solution. Our approach is not directly applicable to transitions between rolling and sliding where the Coulomb friction law is discontinuous. To overcome this difficulty, we introduce a smooth nonlinear friction law, which approximates Coulomb friction. Such a friction model can also increase the efficiency of both rigid-body and compliant contact simulation. Numerical simulations for the different models and comparison with experimental results are also presented.
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Hu, Jian Hua y Yuan Hua Shuang. "Nonlinear Analysis of Piercing Rolling Process by Element-Free Galerkin Method". Applied Mechanics and Materials 26-28 (junio de 2010): 285–88. http://dx.doi.org/10.4028/www.scientific.net/amm.26-28.285.
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During piercing rolling simulation, extreme mesh deformation cannot be solved by the finite element method (FEM). Re-meshing is necessary to prevent the effect of severe mesh distortion. However, the element-free method can solve this problem because the continuous body is discretized with a set of nodes, not meshes. In this paper, three-dimension rigid-plastic element-free Galerkin Method (EFG) is introduced to analyze the piercing rolling process. The approximation functions are calculated considering a moving least squares (MLS) approach. The Newton-Raphson method is used for the solution of the nonlinear system of equations. The equivalent stress, the equivalent plastic strain and the equivalent plastic strain rate obtained by EFG and rigid-plastic FEM are analyzed and compared. The simulation results of the EFG method are in agreement with those obtained by using the rigid-plastic FEM and the effectiveness of the model is verified.
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Jovanovic, Bozidar. "Note on a ball rolling over a sphere: Integrable Chaplygin system with an invariant measure without Chaplygin hamiltonization". Theoretical and Applied Mechanics 46, n.º 1 (2019): 97–108. http://dx.doi.org/10.2298/tam190322003j.
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In this note we consider the nonholonomic problem of rolling without slipping and twisting of an ??-dimensional balanced ball over a fixed sphere. This is a ????(??)?Chaplygin system with an invariant measure that reduces to the cotangent bundle ??*?????1. For the rigid body inertia operator r I? = I? + ?I, I = diag(I1,...,In) with a symmetry I1 = I2 = ... =Ir ? Ir+1 = Ir+2 = ... = In, we prove that the reduced system is integrable, general trajectories are quasi-periodic, while for ?? ? 1, ?? ? 1 the Chaplygin reducing multiplier method does not apply.
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Tătaru, Vladimir Dragoş y Mircea Bogdan Tătaru. "New Aspects Concerning Dynamics of Rigid Solid Body in Plane-Parallel Motion Subjected to Real Constraints. Part One". Land Forces Academy Review 24, n.º 2 (1 de junio de 2019): 175–80. http://dx.doi.org/10.2478/raft-2019-0021.
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Abstract The present paper approaches in an original manner the dynamic analysis of a wheel which climbs on an inclined plane under the action of a horizontal force. The wheel rolls and slides in the same time. The two movements, rolling and sliding are considered to be independent of each other. Therefore we are dealing with a solid rigid body with two degrees of freedom. The difficulty of approaching the problem lies in the fact that in the differential equations describing the motion of the solid rigid body are also present the constraint forces and these are unknown. For this reason they must be eliminated from the differential equations of motion. The paper presents as well an original method of the constraint forces elimination.
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Liu, Rong Chang, Li Dong Chen, Yu Wu, Shu Ying Ma y Li Zhen Feng. "Description of Work-Hardening Layer’s Depth by Soft Coefficient". Key Engineering Materials 419-420 (octubre de 2009): 73–76. http://dx.doi.org/10.4028/www.scientific.net/kem.419-420.73.
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In this paper, by introducing the conceptions of stress condition and soft coefficient, a nonlinear equation is used to describe stress condition of the contacting body along depth. By taking the classical contact problem of two parallel cylinders as an example, we give a quantitative description of work-hardening layer’s depth related to local contact problems by using soft coefficient, and it is theoretically proved that plastic deformation and plastic failure exist objectively in engineering contact problem. The analysis indicates that hardening layer’s depth in the range of 0.43643b(where “b” represents contacting semi-width ), where soft coefficient equivalents to infinity, can be defined as "work-hardening surface layer", depth ranging from 0.43643b to 3b can be roughly defined as "subsurface layer", and depth ranging out of 3b can be defined as "deep layer". Finite element analysis of Ono-rolling specimen shows that measuring method of x-ray of the residual stress is relatively more accurate in the surface layer; however, numerical method can give more accurate results than experimental method in the subsurface and deep layer.
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Jurdjevic, Velimir. "Integrable Systems: In the Footprints of the Greats". Mathematics 11, n.º 4 (20 de febrero de 2023): 1063. http://dx.doi.org/10.3390/math11041063.
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In his 1842 lectures on dynamics C.G. Jacobi summarized difficulties with differential equations by saying that the main problem in the integration of differential equations appears in the choice of right variables. Since there is no general rule for finding the right choice, it is better to introduce special variables first, and then investigate the problems that naturally lend themselves to these variables. This paper follows Jacobi’s prophetic observations by introducing certain “meta” variational problems on semi-simple reductive groups G having a compact subgroup K. We then use the Maximum Principle of optimal control to generate the Hamiltonians whose solutions project onto the extremal curves of these problems. We show that there is a particular sub-class of these Hamiltonians that admit a spectral representation on the Lie algebra of G. As a consequence, the spectral invariants associated with the spectral curve produce a large number of integrals of motion, all in involution with each other, that often meet the Liouville complete integrability criteria. We then show that the classical integrals of motion associated, with the Kowalewski top, the two-body problem of Kepler, and Jacobi’s geodesic problem on the ellipsoid can be all derived from the aforementioned Hamiltonian systems. We also introduce a rolling geodesic problem that admits a spectral representation on symmetric Riemannian spaces and we then show the relevance of the corresponding integrals on the nature of the curves whose elastic energy is minimal.
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Nélias, Daniel, Eduard Antaluca y Vincent Boucly. "Rolling of an Elastic Ellipsoid Upon an Elastic-Plastic Flat". Journal of Tribology 129, n.º 4 (7 de junio de 2007): 791–800. http://dx.doi.org/10.1115/1.2768078.
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The paper presents a numerical analysis of the rolling contact between an elastic ellipsoid and an elastic-plastic flat. Numerical simulations have been performed with the help of a contact solver called Plast-Kid®, with an algorithm based on an integral formulation or semi-analytical method. The application of both the conjugate gradient method and the discrete convolution and fast Fourier transform technique allows keeping the computing time reasonable when performing transient 3D simulations while solving the contact problem and calculating the subsurface stress and strain states. The effects of the ellipticity ratio k—ranging from 1 to 16—and of the normal load—from 4.2 GPa to 8 GPa—are investigated. The reference simulation corresponds to the rolling of a ceramic ball on a steel plate made of an AISI 52100 bearing steel under a load of 5.7 GPa. The results that are presented are, first, the permanent deformation of the surface and, second, the contact pressure distribution, the von Mises stress field, the hydrostatic pressure, and the equivalent plastic strain state within the elastic-plastic body. A comparison with an experimental surface deformation profile is also given to validate the theoretical background and the numerical procedure.
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Tulupov, Viktor D., Mikhail A. Sleptsov y Aleksandrs A. Briedis. "Improving the Reliability of Traction Induction Motors Used in the Electric Rolling Stock". Vestnik MEI, n.º 5 (2021): 92–102. http://dx.doi.org/10.24160/1993-6982-2021-5-92-102.
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The problem of failures of traction machines used in the electric rolling stock (ERS) is considered. In the course of ERS operation with microprocessor control and the use of electric drives with semiconductor converters and induction traction motors (ITMs), it is observed that the service life of bearings reduces from the 2 million km declared by the manufacturer, to 200-600 thousand km. The study of bearings shows the following types of damage: dulling of rolling elements and tracks of the outer and inner rings, grooving, and lubricant degradation. An analysis that was carried out shows that in the majority of cases, the bearings fail as a consequence of a current flowing through them. The currents flowing through bearings are generated due to different mechanisms. A classification of bearing currents is proposed, and possible current flow loops are analyzed. Based on an analysis of literature sources, methods for reducing the bearing currents are given, and their effectiveness is evaluated. To enhance the ITM reliability, several measures to prevent electric current from passing through the bearings have been developed, including the method of plasma deposition of aluminum oxide on the outer ring, which insulates the bearing outer ring from the motor body, and hybrid bearings with ceramic rolling bodies. To select the optimal solution and determine the difference between the outer ring insulation concept and the hybrid concept, operational tests were carried out. Conclusions have been drawn about the expediency of using hybrid bearings with rings made of bearing steel and rolling elements made of bearing silicon nitride (Si3N4).
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Babudzhan, Ruslan, Konstantyn Isaienkov, Oleksii Vodka, Danilo Krasiy, Ivan Zadorozhny y Michael Yushchuk. "Classification of the operating state of rolling bearings with the convolutional neural network with variable dilation factors". Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines, n.º 2 (31 de diciembre de 2021): 106–11. http://dx.doi.org/10.20998/2078-9130.2021.2.249274.
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The work describes rolling bearings operation data processing, and their use in the problem of constructing a mathematical model of the binary classification of the operating state of bearings by the method of a convolutional neural network with varying factors of dilatation of the kernel of convolutional layers. To classify bearings with defects, we used vibration acceleration data from our own test bench and a publicly available data set. The work also investigated a method for generalizing the classification of bearing signals obtained as a result of fundamentally different experiments and having different standard sizes. To unify signals, the following processing method is proposed: select data areas with displacement, go to the frequency space using fast Fourier transform, cut off frequencies exceeding 10 times the shaft rotation frequency, restore the signal while maintaining 10 shaft rotation periods, scale the received signal by dividing it by its diameter orbits of the rolling body and interpolate the signal at 2048 points. This algorithm also allows to generate a balanced sample for building a mathematical model. This feature is provided by varying the step of splitting the initial signal. The advantage of this algorithm over the classical methods of oversampling or undersampling is the generation of new objects that specify the statistical parameters of the general population. The signal processing algorithm was used both for binary classification problems within one dataset, and for training on one and testing on another. To increase the data set for training and testing the mathematical model, the bootstrapping method is used, based on multiple generation of samples using the Monte Carlo method. The quality of the mathematical model of binary classification was assessed by the proportion of correct answers. The problem is formulated as the problem of minimizing binary cross entropy. The results obtained are presented in the form of graphs demonstrating the neural network training process and graphs of the distribution density of metrics.
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Kukielka, Leon, Michal Szczesniak, Radoslaw Patyk, Agnieszka Kułakowska, Krzysztof Kukielka, Sylwia Patyk, Katarzyna Gotowala y Dražan Kozak. "Analysis of the States of Deformation and Stress in the Surface Layer of the Product after the Burnishing Cold Rolling Operation". Materials Science Forum 862 (agosto de 2016): 278–87. http://dx.doi.org/10.4028/www.scientific.net/msf.862.278.
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The article presents the results of computer modelling and numerical simulations the deformation and stresses occurring in the surface layer of the product after the burnishing cold rolling operation. Technological processes were considered as a geometrical and physical boundary and initial value problem, with unknown boundary conditions in the contact zone. An incremental model of the contact problem between movable rigid or elastic body (tool) and elastic/visco-plastic body (object) in updated Lagrange formulation, for spatial states (3D) was considered. The incremental functional of the total energy and variational, non-linear equation of motion and deformation of object on the typical step time were derived. This equation has been discretized by finite element method, and the system of discrete equations of motion of objects was received. For solution of these equations the explicit methods was used. The applications were developed in the ANSYS/LS-Dyna system, which makes possible a complex time analysis of the states of displacements, strains and stresses, in the workpieces in fabrication processes. Application of this method was showed for examples the modelling and the analysis of the asperities with apex angles θ = 85°, 120° and 156°. The Bielajew point using finite elements methodology was indicated. The simulation results were verified experimentally.
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Telegin, A. I., E. V. Gusev, G. I. Volovich y S. G. Nekrasov. "FORMALISM FOR SOLVING THE FIRST PROBLEM OF THE DYNAMICS OF WALKING AND WHEEL-WALKING MACHINES". Bulletin of the South Ural State University. Ser. Computer Technologies, Automatic Control & Radioelectronics 24, n.º 2 (mayo de 2024): 39–55. http://dx.doi.org/10.14529/ctcr240204.
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The aim is to solve the first problem of the dynamics of machines moving their bodies with the help of legs, i.e., to calculate the control actions of the leg actuators that provide the given dynamics of the absolute motion of the body and satisfy the constraints, when fulfilled, there is no sliding of the supporting legs relative to the supporting surface. The research methods are related to system analysis, mechanics of body systems and robotics. We consider walking and wheel-walking machines with legs suspended from the body, in which the last kinematic pair is translational, there is no controlled foot, and the foot and the supporting surface interact at a single point. The resultsof the study contain analytical formulas for calculating dynamic reactions at the points of contact between the legs and the supporting surface, as well as driving forces and moments of forces in the drives of the supporting and carrying legs, providing a given motion of the body relative to the supporting surface, as well as its corresponding relative motion of the bodies of the supporting legs. A formalism for solving such problems is described, based on inverse vector recurrence formulas for calculating forces and moments of forces of dynamic reactions in kinematic pairs of tree-like systems of bodies with closure of the last body of the branch on the supporting surface. This formalism is extended to wheeled, wheel-walking and walking machines, which is demonstrated by appropriate examples. Analytical conditions for realizing a step without slipping of the support legs relative to the support surface are written down. Two simple wheel-walking machines, consisting of a linear electric drive and a driven (passive) wheelset, are proposed for the experimental determination of sliding and rolling friction coefficient values. In analytical forms of deduced calculation formulas (equations and inequalities) the structural, geometric, inertial and kinematic parameters of the investigated machines are explicitly expressed. The proposed formalism is demonstrated on the solutions of four problems from simple to complex through the reuse of formulas. Conclusion. The obtained mathematical models can be used in the processes of calculation and design of similar machines and their layouts.
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Khikmatov, Farkhod, Meirkhan Baltaev, Irina Soboleva, Yahyo Xurmatov y Abdusaid Yuldashov. "The body of a dynamometer wagon for special technical purposes". E3S Web of Conferences 458 (2023): 03021. http://dx.doi.org/10.1051/e3sconf/202345803021.
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The development of new and improvement of existing railway rolling stock wagons is an urgent task of our time, providing for cost reduction, both in the process of creation and operation, and in the maintenance of the wagon fleet. The purpose of the work is to modernize the body of a dynamometer wagon for special technical purposes using modeling. To determine the loading of the structural elements of a dynamometer wagon, a calculated three-dimensional model of the wagon body was developed, the reinforcement points of the wagon frame were determined. Compression/tensile strength tests of the wagon were performed on a stand for loading the frames of wagons and elements of coupling devices. The stress-strain state of the wagon structure is determined when statically applied longitudinal test loads are applied to it. The test results and the stress-strain state of the design of the prototype wagon, under the action of statically applied longitudinal compressive and tensile test loads, showed that the proposed design of the wagon meets the established strength requirements, while no visible damage and residual deformations were found in the design of the prototype wagon. The developed design of the dynamometer wagon body can be included in both freight and passenger trains, which solves the problem of efficient and safe use of locomotives when operating trains on mountainous sections of railways of the Republic of Uzbekistan.
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He, Mianchao, Yuxi Liu, Zhiping Zhang y Yinghua Sheng. "Rolling active load relief technology for launch vehicle bundled with common booster core in face". Journal of Physics: Conference Series 2764, n.º 1 (1 de mayo de 2024): 012061. http://dx.doi.org/10.1088/1742-6596/2764/1/012061.
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Abstract The aerodynamic interference forces and moments of different windward surfaces of a launch vehicle bundled with a common booster core in the face vary considerably. The servo mechanism is laid out to maximize the control capability of the rocket at a certain angle. The dominant surface of the rocket is determined by aerodynamic interference and control capability. For the problem of large interference and asymmetry during the flight of a nominal rocket, a rolling active load relief control law based on the optimization of the spatial interference vector is proposed. The direction with the largest spatial interference vector is obtained online by visual acceleration information. By adjusting the rolling program angle, the rocket will align the dominant face with the direction of the largest interference when flying through the windy area. And then, the rocket obtains a good control effect. The simulation results show that the control law proposed in this paper can effectively improve the adaptability of the rocket control in the case of sudden changes in wind direction. It achieves the purpose of reducing the static load of the rocket body structure during the flight.
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Kadnianka, E. V., S. V. Shil’ko y D. A. Chernous. "A Solution Method for the Contact Problem of Free Rolling on a Rigid Foundation of a Cylindrical Body with a Deformable Rim". Trenie i Iznos 45, n.º 1 (2024): 5–15. http://dx.doi.org/10.32864/0202-4977-2024-45-1-5-15.
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Ovrén, Hannes y Per-Erik Forssén. "Trajectory representation and landmark projection for continuous-time structure from motion". International Journal of Robotics Research 38, n.º 6 (15 de abril de 2019): 686–701. http://dx.doi.org/10.1177/0278364919839765.
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This paper revisits the problem of continuous-time structure from motion, and introduces a number of extensions that improve convergence and efficiency. The formulation with a [Formula: see text]-continuous spline for the trajectory naturally incorporates inertial measurements, as derivatives of the sought trajectory. We analyze the behavior of split spline interpolation on [Formula: see text] and on [Formula: see text], and a joint spline on [Formula: see text], and show that the latter implicitly couples the direction of translation and rotation. Such an assumption can make good sense for a camera mounted on a robot arm, but not for hand-held or body-mounted cameras. Our experiments in the Spline Fusion framework show that a split spline on [Formula: see text] is preferable over an [Formula: see text] spline in all tested cases. Finally, we investigate the problem of landmark reprojection on rolling shutter cameras, and show that the tested reprojection methods give similar quality, whereas their computational load varies by a factor of two.
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KOCHERGIN, V. V., A. A. BUKHANTSEV, I. G. PANKRATOVA y O. A. RUSANOV. "Experience in ensuring the strength of the supporting structures of locomotives and electric multiple units". Vestnik of the Railway Research Institute 78, n.º 2 (5 de junio de 2019): 67–73. http://dx.doi.org/10.21780/2223-9731-2019-78-2-67-73.
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To ensure fatigue strength of metal structures in mechanical engineering, various approaches are practiced. One of them allows for the appearance of cyclic stresses in details with amplitudes exceeding the fatigue limit. Typically, this approach is justified where the loads are fairly regular and ample opportunities for fatigue testing exists, but the requirement of a minimum metal consumption is critically important as well. Another approach to ensuring fatigue strength does not allow the possibility of cyclic stresses with amplitudes exceeding its endurance limit in the designed structure. With regard to the supporting elements of locomotives and electric multiple units (EMU) to ensure the fatigue resistance characteristics in Russia and the CIS countries, the second of these approaches has been implemented and successfully practiced for many years. Its purpose is to ensure the absence of fatigue damage in the parts of the carriage and the body during the designated service life. Relevant requirements for strength and dynamic qualities for these types of rolling stock, as well as the method of conducting dynamic strength tests are currently formalized in the standards. The article presents the main provisions of the methodology currently used on the railways of the Russian Federation and CIS countries to control the strength requirements of load-bearing structures of locomotives and EMUs, as well as the admission of these types of rolling stock to operation. Types of dynamic strength tests are described, strength indicators are listed, methods for their determination are indicated. Today, this technique successfully solves the problem of the strength of load-bearing structures of traction rolling stock.
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Yu, Zheng, Mu Longtao y Zhao Junhao. "Investigation of rolling bearing weak fault diagnosis based on cnn with two-dimensional image". Дефектоскопия, n.º 1 (15 de enero de 2023): 63–76. http://dx.doi.org/10.31857/s0130308223010074.
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In this paper, we choose convolution neural network (CNN) as the method to diagnosis weak fault of rolling bearings. In order to improve the training effect of CNN, different two-dimensional image conversion algorithms which include Gramian angular sum difference fields, wavelet time-frequency diagram, Markov transition field are introduced in to convert one-dimensional time series of bearing vibration signals into images. To relieve the pressure of hardware calculation and shorten the time of training and validation, we use the piecewise aggregate approximation (PAA) to compress the data as much as possible while preserving the whole signal information. We add the batch normalization layer to avoid the gradient saturation problem of ReLU function and minibatch method is used to overcome the instability of stochastic gradient descent with momentum (SGDM) while designing CNN. Each kind of images are made as the training sample, and the results show that both the wavelet time-frequency diagram and the Gramian sum or difference angle field diagram can better identify the fault state, and the wavelet time-frequency diagram was relatively better. By comparing with different recurrent neural network (RNN) diagnosis models, the validity of the model was proved. At the same time, the model is applied to the performance degradation identification of fault parts, and the results shows that the model can effectively identify the degradation of inner ring, outer ring and rolling body, while the accuracy of inner ring and the outer ring is better. This paper provides a new idea for weak fault diagnosis of rolling bearings.
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Mudrov, Alexander P., Fanil F. Khabibullin, Gennadi V. Pikmullin y Zurab D. Gurgenidze. "Synthesis of spatial five- and six-letter mechanisms with rotational pairs by the movement of the output link". BIO Web of Conferences 52 (2022): 00046. http://dx.doi.org/10.1051/bioconf/20225200046.
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The article discusses spatial mechanisms with rotational pairs that allow the movement of the output link or working body with a given accuracy while ensuring the necessary rigidity and reliability of the structure. Its durability is also significantly increased, energy losses are reduced, since all hinge assemblies (rotational kinematic pairs) are made on rolling bearings and are reliably isolated from the external environment. The article is also devoted to the synthesis (design) of functional spatial six-branch mechanisms with rotational pairs reproducing with a given accuracy the linear function of the change in the angle of rotation of the output link, provided it is fully rotatable. The objective function and dependencies necessary for the design of such mechanisms are obtained and an algorithm for solving this problem in CAD is developed.
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Obradovic, Slobodan. "Quality control of the hindside's axis stabilization using the instrumental servo system". Facta universitatis - series: Electronics and Energetics 16, n.º 1 (2003): 67–81. http://dx.doi.org/10.2298/fuee0301067o.
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In up to date wars, gunfiring from the vehicle in motion has become the basic way of action for operational armored vehicles (conveyors and tanks). Because of the rolling of the vehicle's body (caused by moving on the ground) and the change in the target coordinates (because the target is in motion, as well), the shooting accuracy in comparison with shooting accuracy in the case of shooting passive targets from the fixed position is substantially decreased. The particular problem is to measure the quality that is, to measure the error of achieved stabilization. This study describes the new, simple (and cheap) simulation method for the stabilization quality check, which enables the complete laboratory simulation of driving over the optional terrain in the real conditions, as well as the undisturbed examining in the extreme temperature conditions.