Journal of Machinery Manufacture and Reliability最新文献

Electroplastic rolling is considered as a way to increase the deformability of industrial titanium alloys VT6 and TiNi with the shape memory effect and as a possibility of obtaining a fine-grained structure with increased strength characteristics in these alloys.

A problem is formulated to investigate the influence of various factors of a single grain cutting process on the formed microrelief of the grain trace on the workpiece surface, such as the grain shape and cutting depth. Based on finite element modeling in the ANSYS finite element analysis software system in the Workbench environment of the interaction of abrasive grain with the workpiece, studies were carried out and the values of the geometric parameters of the microrelief of grain trace on the workpiece surface were obtained: depth, width, and mark area in the cross section, as well as the width, height, and area of the left and right piles in cross section. In addition to the geometric characteristics, the coefficient of material pushed into heaps was determined. The research methodology used made it possible to obtain the geometric characteristics of the microrelief of the trace from the abrasive grain and to determine their dependence on the cutting process factors: the abrasive grain shape and the depth of its penetration into the workpiece.

The article considers the adequacy of the model, which takes into account the dynamics of phase interaction over time, thereby allowing you determine the instantaneous values of pressure and temperature in a macroscopic thermodynamic system.

A mathematical model is developed and an original technique is proposed in order to evaluate the effect of pressure on properties during the formation of crystallizing metal. It has been established that, for an efficient process of heat exchange between the casting and the mold, it is necessary to increase the wall thickness of the mold gradually from the periphery to the center. Relationships are obtained that make it possible to calculate the amount of heat that the metal exchanges with the mold at the first stage. The results have made it possible to find out that the process control should be brought into line with the rate of crystallization. In addition, the volume of metal required for the compensation for shrinkage of the crystallized metal should be pressed into the casting in the course of each fixed period of time.

This article describes the design of an appliance for improvement of the technology for repairing elements of the clutch using composite polymer materials.

The methodology and results of theoretical and experimental studies of cutting elements of rotary-type working bodies for development and grinding of soils for the purpose of their subsequent strengthening with binding materials (cement, organic binders) during the construction of highways are provided. A stand for physical modeling of the working processes of machines of this type (roadmixer, road harrow) is proposed.

It is shown that failures of cylindrical keyed joints are caused by two main factors: insufficient strength and violation of accuracy standards. As a result of studying the pieces of cylindrical joints ∅50Н8/h9, it is revealed that the dispersion of the inner coupling diameter and the outer shaft diameter obeys the law of normal distribution. It is established that the probability of spoilage occurring in all fits is low and the overwhelming majority of the formed joints will meet the requirements of factory accuracy even if there is a certain percentage of spoilage in the couplings in terms of the base hole and groove width. It is recommended to calculate the force fitting for the cylindrical connection, which ensures the rated torque transfer specified in the gearbox and coupling documentation.

The issues of cavitation processes in radial bearings are discussed. The operating conditions of such bearings and the effect of cavitation on their operation are considered.

A finite element model has been developed, in which in the course of laser shock processing an elastic preliminary stress is generated in the material. The results are compared with the experimental results, which shows their satisfactory convergence. It is shown that there is a linear relationship between preliminary stresses and compressive residual stresses in the case when the final compressive residual stresses are in the range of [–20%, –100%] with respect to the yield strength. It has been established that the presence of preliminary tensile stresses in the material leads to a higher value of the final compressive residual stresses and the penetration depths thereof.

The intensive development of human–machine user interfaces (ergatic systems) requires the development of new recommendations for the preservation and promotion of the health of operators who, by virtue of their professional activity or duty, are users of these systems. There are various standards that regulate the relevant hygiene requirements and norms; however, the periodic introduction of new algorithms and the emergence of new interfaces leads to the development of new recommendations. From this position, this article discusses human–machine system interfaces and big data issues. The concepts of allostasis as a model of predictive regulation and of allostatic load as an integral indicator of the influence of stress factors on operators of ergatic systems are presented. Hygienic recommendations are given for interfaces of human–machine systems to improve the information ergonomics of interfaces and reduce the load on operators.