Journal of Machinery Manufacture and Reliability最新文献

The issues related to the design features and operating conditions of turbochargers are addressed briefly. In addition to long-established technical solutions, new, more advanced options that are intended for further scientific research and practical application in turbocharger bearings are revealed.

Synthesis of engineering solutions for energy storage systems is of great importance for the development of the economy, where renewable energy sources are becoming more and more in demand. Therefore, research, development, and application of renewable sources constitute one of the most important tasks for environmental protection and creation of perspective transportation and energy systems. To increase efficiency, it is necessary constantly to improve technical solutions and introduce new technologies. The development of energy storage systems, with a special focus on mechanical storage systems, is considered. An advanced morphological approach is used for the analysis. A number of engineering solutions are considered, and a hybrid device combining a hydraulic accumulator and a gravity energy storage system is investigated in detail. Conclusions are drawn about possible applications of the engineering solutions found.

This article presents an analysis of the results of a study on a promising method for producing functionally graded composite materials using “cold” gas dynamic spraying technology. In particular, for the Al–Al₂O₃ composite, the influence of the ceramic component content on the change in the coefficient of thermal linear expansion is determined. The results can be used in the design and creation of materials in thermally loaded components to reduce stresses by adjusting thermal gaps.

For the description of power transmission through drive links, a system of linear first-order differential equations has been applied taking into account the accelerations and rates of changes in stresses under torsional and transverse oscillations. An eighth order vector equation has been derived and solved, including algebraic elements, making it possible to calculate the fluctuations of stresses and motion velocities in any link of the system to a first approximation with the use of an engineering method. For a particular drive, the effect of the inertial properties of the load and the features of resistance torque formation exerted on the dynamic characteristics of the drive has been analyzed.

The requirements for woven electric heaters that provide both a contact thermal effect on a person and obtaining a human response to this effect, which is a novelty, are provided. A comparison of the results obtained using woven electric heaters with heat-generating elements made of steel wire and carbon threads is carried out. The experiments have confirmed the validity of these requirements when producing and using woven electric heaters with heat-generating elements made of materials with different physical properties. The results may be of interest to specialists in the field of thermal physics, electrical engineering, physiology, etc.

The methodology of combined application of acoustic emission diagnostics and vibration diagnostics for monitoring the state of damage of samples made of 17GS1 pipe steel with a combined stress during the development of a dominant crack is considered. In the experiments, the stress concentrator is a transverse weld subjected to local crumbling and a guide scratch to a depth of up to 3 mm across the entire sample width. Such a concentrator simulated the effect of buried reinforcement on the weld when laying a pipeline through a water obstacle.

Wave strain hardening technology has appeared relatively recently and is successfully used in various industries to increase the product durability. Modeling is a necessary part of this technology. The long-term goal is to create combined technologies with wave strain hardening and predicted results. Modeling of combined technologies involves sequential modeling of different processes, implying data exchange while calculating. A successful experience of step-by-step modeling of combined processes is presented, the adequacy of the results of which is confirmed by experimental data.

This article addresses the search for a design solution aimed at improving the labor productivity of operators using next-generation block-type woodworking equipment with six saw modules for producing parquet and edged boards. The nature and characteristics of the saw module’s movement allow for new technical solutions that facilitate the replacement of saw blades of varying lengths without the need to change the correcting masses in the hinged joints. The proposed design and technological solution is particularly relevant for solving the problem of removing the saw blade from the resonance zone of its operational frequency of rotation. The quality, range, thickness variability of the produced timber, and the productivity of the equipment significantly exceed the characteristics of world-class machines with similar functional purposes.

Friction stir welding of metals is discussed. A method for calculating the occurrence of resonance in terms of periods and frequencies of reflected waves is proposed. Examples of calculations are given.

A promising approach to the glue-threaded assembly of automotive bodies that can replace conventional riveting and glue-riveting technologies is described. The results of comparative strength tests of glue-threaded and glue-riveted joints are given for the samples made of carbon fiber and aluminum.