Journal of Machinery Manufacture and Reliability最新文献

The development of methods for the approximation synthesis of flat lever mechanisms in the Kazakh school of the theory of machines and mechanisms is considered. Particular attention is paid to the practical aspects of applying approximate kinematic geometry to problems of synthesizing guides and moving, transmission, and adjustable mechanisms. Improved numerical–analytical methods of synthesis are proposed taking multiple quality criteria of mechanisms into account. To improve the design efficiency, a multicriteria optimization algorithm was developed using modern machine learning methods, in particular DeepSurNet-NSGA and others. New designs of mechanisms are presented, including 6-link mechanisms for a walking robot leg, mechanisms for exoskeletons of the lower and upper limbs, as well as a hinge-lever mechanism, and a Cartesian manipulator with two degrees of freedom. The prospects for applying the obtained solutions in robotics, biomechanics, and mechanical engineering are substantiated. The role of intelligent systems in the automation of synthesis and analysis of the functional capabilities of mechanisms is emphasized.

Laser shock processing is an advanced modern technology for hardening the surfaces of metallic materials, using laser shock waves to produce strong plastic deformation, significant compressive residual stresses, and refinement of grains. These factors together increase the fatigue and strength characteristics of materials. In this paper, I derive an equation for the residual strain induced by laser shock processing technology in viscoelastoplastic materials. Particular attention is paid to the formation of microdimples on the surface caused by laser shock waves, and an approximate equation is derived to determine their maximum depth. Тhe depth of microdimples is likely noted to serve as an indirect indicator of the effectiveness of laser shock processing and of the degree of improvement in fatigue properties of the material. The obtained results increase the number of potential areas of application of laser shock processing in various industries.

The results of the experimental study of temperature dependences in the cutting zone on the processing mode of polymer materials used in shipbuilding are presented. Cutting temperatures are determined for various milling modes of these polymer materials. The dependences of the maximum average temperature in the cutting zone on cutting mode parameters (cutter rotation speed and feed rate) are plotted and presented as response surfaces. Numerical dependences are determined to calculate the maximum average temperature in the cutting zone. According to the plot analysis, these dependences are nonlinear and demonstrate extremum points. This allows one to determine optimal processing modes with the lowest cutting temperature. Thus, optimal milling parameters are determined using the results obtained.

Numerical analysis by the finite element method of welding deformations in a thin-walled structure is considered. A comparison was made with the results of an experiment in which semiautomatic arc welding in a carbon dioxide environment with a consumable electrode was used to obtain a T-joint from standard carbon steel St3sp. In the numerical solution of thermoelastoplastic problems in the Marc system, the Goldak double ellipsoidal heat source model was used, taking into account large deformations and nonlinearity of the steel properties depending on temperature. In connection with fluctuations in voltage, current, and, accordingly, arc power during the welding process, the influence of different functional dependencies of the arc thermal power on time on the residual deformation of the structure was analyzed during the simulation. As residual deformations, deformations leading to nonflatness are analyzed as the most significant ones. The developed design model with welding process parameters provides the possibility of accurately forecasting residual deformations and adjustments to the technological process for reduction of geometric deviations.

The organization of “smart” manufacturing of solid axial metal-cutting tools, based on automated dimensional assurance during grinding operations, is considered. A methodology for optimizing the grinding process of solid axial metal-cutting tools, implemented through the integration of modern control means, is proposed. The practical significance of the development is proven through the minimization of time and resource costs, reduction in the probability of defects, and increased overall production efficiency. The results of testing the developed methodology at the enterprise JSC New Instrumental Solutions are presented.

An additive manufacturing technology for polymeric composite materials based on the fused thread fabrication (FFF) technology has been developed and studied in order to provide an increase in the strength of printed products. Different approaches to reinforcing products with continuous fiber in the course of the printing process are considered. A five-axis printing method is proposed, which makes it possible to perform the spatial reinforcement of printed products using different patterns. The proposed method is implemented as a five-axis printing device and software (slicer) for the automatic preparation of controlling programs for printing with the use of reinforcement. The mechanical properties of reinforced printed products have been studied using tensile testing in accordance with GOST (State Standard) R 56785–2015. Approximate values have been obtained for the mechanical characteristics of reinforced samples under tension, and the effect of reinforcement exerted on the failure mode has been analyzed. A conclusion is drawn concerning the scope of application of the proposed FFF printing technology at the current level of development.

In this paper, a method for machining bevel gears in small-scale production using the PowerMill CAM system has been discussed. The effect of thte tool diameter and various process strategies, namely, Flow Finishing, Parametric Offset, and Blade Finishing, on machining time has been determined. In this study, it has been found that for small batches, the Flow Finishing strategy is more effective, while as batch size increases, the Blade Finishing strategy becomes more efficient. A regression equation characterizing the dependence of machining time on the number of parts has been obtained. The obtained results can be used to optimize the manufacturing process of bevel gears.

Using machine vision technology to manage assembly kits in a warehouse allows for automated inventory control and management, improving the accuracy and speed of data processing. The implementation of such systems reduces the influence of the human factor, minimizes errors during inventory, and ensures prompt updating of information in the accounting system. This article discusses methods for recognizing objects using computer vision, including image processing, marker or barcode detection, and the use of neural network algorithms for component classification. The advantages and limitations of different approaches are analyzed. The results of this study demonstrate the effectiveness of using machine vision for automated inventory control of assembly kits, which helps optimize logistics processes and reduce warehousing costs.

For the first time, based on correct experiments that exclude the negative effects of temperature variability and mutual misalignment and/or axial displacement of the rings, torque values for the rotating resistance forces depending on time have been obtained for a single-row radial ball bearing loaded with a radial force. An analysis of the experimental studies on the torque of the rotating resistance forces of single-row radial ball bearings conducted by J. Goodman, R. Stribeck, and others is presented. It is shown that the experimental dependences obtained at the Mechanical Engineering Research Institute of the Russian Academy of Sciences (IMASH RAN) representing the inherent characteristics of the studied ball bearing can be used for an integrated assessment of its quality.

The nonlinear dynamics of spacecraft power structures in the form of closed cylindrical shells under the action of an external alternating load are investigated. To study the nonlinear dynamics, a mathematical model of the described structure was constructed taking into account the geometric nonlinearity according to the T. von Karman model and the Kirchhoff–Love kinematic hypothesis. The resulting system of differential equations is reduced to the Cauchy problem using the Bubnov–Galerkin method, after which it is solved using the Runge–Kutta method in time. It is shown that the transition of oscillations of a closed cylindrical shell from harmonic to chaotic occurs according to a combination of the Feigenbaum and Ruelle–Takkens–Newhouse scenarios.