Journal of Machinery Manufacture and Reliability最新文献

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.

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.

Methods of mathematical planning of a multifactorial experiment and processing of the obtained results are used to study the dependence of the optimization parameter—the size of the ground grain—on the rotor speed and the gap between the rotor and the stator. Based on mathematical calculations, a regression equation was obtained in the form of a first- and second-order polynomial, characterizing the contribution of each factor to the process of grinding grain products in conical-rotor mills.

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.

Alloys with shape memory based on TiNi are characterized by maximally high characteristics of shape memory and superelasticity, allowing them to be used as implants for various purposes. The enhanced functional properties of the alloys are attributed not only to their physical nature but also to their microstructure, where it is desirable to have grain sizes in the nanostructured range. A new method for obtaining nanostructures based on plastic deformation accompanied by an electric current is discussed.

The application of electroplastic deformation to form semifinished implants made of the titanium alloy VT6 is considered. It is shown that the use of electroplastic deformation avoids the formation of cracks and increases the strain rate by five times.