Journal of Machinery Manufacture and Reliability最新文献

The results of semianalytical calculation of the critical buckling loads and load-bearing capacity of laminated composite panels having different geometric shapes in plan in the course of loading with compressive and tangential forces in the plane of the layers are presented. The stability problems of orthotropic layered plates with variable geometric parameters have been solved by the Rayleigh–Ritz method with approximation of the deflection function by orthogonal Krylov polynomials. The effect of shape, the method of fastening the panels, and the arrangement pattern of reinforcing fibers in the layers of the composite has been studied. Rational reinforcement patterns that correspond to the highest critical buckling load for nonrectangular and shallow curved panels have been revealed. The load-bearing capacity under supercritical strain has been assessed based on the Tsai–Wu strength criterion.

The possibility of using a more economical process—intense plastic deformation of superalloys by pressure with torsion under isothermal conditions—is substantiated. It is shown that in this case the critical load on the tool is significantly reduced and the single-transition process of deformation accumulation necessary for uniform grain refinement in the material of large superalloy workpieces is ensured. A die design has been proposed for implementing the torsional pressure method for producing gas turbine engine disk blanks under isothermal conditions.

The results of testing the technology for modeling crack development using the finite element analysis in a three-dimensional formulation are described. The results are compared with known experimental data, and a number of inconsistencies are identified and explained. The forecasts and recommendations for improving the corresponding software are given.

The development of technological processes for manufacturing machine tool parts with wear-resistant coatings deposited during their manufacturing is discussed. The performance features of tool parts during mechanical treatment of workpieces made of hard-to-cut materials is analyzed, and the use of gas-thermal coatings is substantiated to ensure the operational and technical characteristics of the products under consideration.

The nonisothermal elastohydrodynamic problem for an oil film journal bearing is considered. The mathematical bearing model is presented. A method for joint numerical solution of nonisothermal lubrication equations and contact deformation equations is presented. The results of numerical calculations are compared with known experimental data on the minimum thickness of the lubricating layer and the maximum temperature in the lubricating layer.

The vibrations of a three-section boom of a concrete pump in the vertical plane on a three-mass dynamic system are considered separately from the torsional vibrations of the boom and its vibrations in the horizontal plane. The differential equations are based on the generalized Hooke law. The values of the periods of natural oscillations of the boom T₁ = 1.33 s, T₂ = 0.32 s, and T₃ = 0.132 s and the corresponding forms of these vibrations are given. It has been shown that when the pump performance is close to the maximum, resonance at a low frequency is possible. Some positions and modes of operation of the boom are considered, in which significant additional dynamic loads may arise in its middle section. Recommendations are given on ways to reduce the dynamics of a concrete pump boom in the vertical plane.

The results of a comprehensive study of temperature modes of bearing units of drive shaft joints under rated loads. Based on experimental studies and modeling of temperature fields, a scientific and methodological basis has been developed for the practical support of automatic thermal diagnostics of moving bearing units during noncontact measurement of their temperature in motion.

The results of a feasibility study on the effectiveness of using various flange lubricators are presented using the example of equipping VL-80 electric locomotives with contact and liquid flange lubrication. The effect-forming factors obtained during the use of flange lubricators and the distribution of effects between the Traction Directorate and the Service Company that provides servicing of locomotives with installed flange lubricators are determined. A comparative analysis of two scenarios is performed, using contact and liquid type flange lubricators and a comparison of the main indicators determining their technical and economic efficiency.

This paper provides the results of fatigue strength tests of structural materials including grade St45 steel and VCKh60-2 high-strength cast iron with plasma coatings. These coatings have a relatively large thickness and consist of the powder composition of EP-109 (KhN56VMKYu) heat-resistant nickel alloy and Al–Mg powder. Experiments have allowed deriving mathematical models to describe the patterns of the influence of the plasma spraying process modes on the fatigue strength of the tested structural materials.

The scientific results of modeling a production manipulator are presented. Modeling a production manipulator makes it possible to study its operation in a virtual environment, to optimize the production processes of finished products, and to achieve maximum efficiency in the operation of a machine-building enterprise. The production manipulator is a multipurpose complex device due to the replaceability of the gripper module. The production manipulator was simulated using the Siemens software product NX version 10.