Sucker-rod pump plant operation is accompanied by inertial and shock loads, affecting the fatigue strength of sucker rods and causing possible accidents. This work proposes the original design of a shock absorber of a sucker-rod string. The peculiarity of the proposed design is the usage of thin plate packages as a bearing elastic element of the shock absorber. This approach to the elastic element’ design provides the shock absorber to be easy to manufacture and operate. Sucker-rod string protection from extra load will increase the sucker-rod pump plant efficiency in general. This study aims at developing shock absorber’s design and studying its most important performance options—strength and rigidity. A mechanical and mathematical model of a shock absorber’s elastic element was developed in order to specify its deformation. A package of thin plates was modelled as an equivalent solid plate with a cylindrical rigidity providing equal properties of the solid model and the plate package. This model makes possible to describe analytically the stress-strain state of the shock absorber bearing elements. The work presents the final expressions of the shock absorber’s strength and rigidity assessing in a convenient form for engineering practice. The numerical approbation of the obtained analytical results was carried out as the case of a plate elastic element. The authors give recommendation on the bearing unit’s design of the shock absorber.

The new design of a resilient element for application in drilling devices of vibration protection is presented. A cylindrical shell with a cut along its generatrix is the peculiarity of the proposed design. The presented resilient element has high loaded and damping properties upon cross dimension hard restriction condition. Besides, the design is simple, technological and low cost. The drilling shock absorber is tested, which is manufactured on the base of several slotted shell resilient elements, operating in parallel manner. A calculation method for slotted shell resilient elements for drilling devices vibration protection is given. This work presents results of slotted cylindrical shell study in conditions of contact interaction with a resilient filler. To provide the research, the authors have developed a verified numerical model of the shell resilient element with a slit and used iterative algorithms for contact problem solving, considering contact surface friction. The stress-strain state of the shell resilient element of the drilling shock absorber was analyzed. Strength of the structure is evaluated by the energy criterion. Hysteresis loops were developed and analyzed for some histories of resilient element cyclic loading. The obtained results make possible rather accurately to take into account effect of the shell and the filler material resilient characteristics, their geometrical parameters and tribological properties on operational characteristics of drilling devices for vibration protection. In its turn, this makes possible to use efficient drilling vibration protection devices, develop vibroinsulator shell designs by the criteria of maximum compliance and required damping level.

Today, pipelines are the safest and most economical way to transport petroleum products and one of the key components of modern energy infrastructure. Nevertheless, pipeline systems are associated with certain risks that can lead to environmental disasters. The idea of carrying out this study was initiated by the results of the survey of the overpasses of the long-used oil pipelines laid in the mountainous area of the Carpathian region. Defects such as a change in the shape of the pipe and local bulges in the area of oil pipeline support nodes were detected. The explanation of the described problem is separate from the typical algorithms of design calculations, which are offered to manufacturers by current directive documents. The desire to provide an explanation and quantitative assessment of the detected defects became the main motivation for writing the article. An analytical model of the interaction of the oil pipeline with the rigid support has been developed. Additional internal loads in the cross-section of the pipe and displacement of its middle surface, which arise as a result of such interaction, are determined. The method of determining the reaction in the intermediate support of the overpass of the oil pipeline has been developed, considering the properties of the soil base in the underground sections and the mounting gap in the support node. The analytical dependence was obtained to determine the additional hoop stresses that arise in the oil pipeline due to the contact of the pipe with the support. The unambiguous relationship between the maximum additional hoop stress and the reaction in the support node was established. The dependence of additional hoop stresses on the geometric characteristics of the pipes was analyzed. The obtained research results are tested on the real structure of the overpass of the Druzhba oil pipeline, built in the Carpathians. In general, a simple engineering technique has been developed that allows analyzing the behavior of the oil pipeline support node and provides the numerical correction to the traditional strength assessment formulas, which determine the equivalent stresses in the oil pipeline.

The formation of phosphate binders in systems based on orthophosphoric acid and the most common refractory fillers in foundry technology (quartz dust, zircon ZrSiO₄, and kyanite‐sillimanite Al₂SiO₅) has not been previously studied. The phase composition of these inorganic binders was studied, and the formation of silicon SiP₂O₇ and zirconium ZrP₂O₇ pyrophosphates was confirmed. The study by differential thermogravimetric analysis in the temperature range of 20–1000°С established the fact that the formed binders are thermally stable and do not emit harmful gaseous substances. The obtained results of the studied binders make it possible to develop new environment‐friendly core mixtures of thermal hardening.

In foundry production, the duration of metal crystallization of the cast part, as well as the distribution of the thermal field, are described by systems of analytical equations. There are a number of methods for modeling these processes, but their theoretical basis was formed at the end of the twentieth century, and it needs to be updated and clarified. Therefore, the aim of our work is to develop a new analytical method for researching the distribution of thermal fields in cast parts during crystallization. For the first time, on the basis of own analytical and thermophysical developments, it developed the analytical method for researching the thermal field of the casting during crystallization and cooling, which is based on establishing the kinetics of cooling of the casting surface in the foundry mold, the advancement of the crystallization front from the surface to the center of the casting, and the distribution of temperatures in the solid and liquid parts of the casting. The method is expressed in a number of analytical formulas, each of which describes the specific thermal process that occurs in the casting. The developed analytical method was used to research the crystallization of the casting in a one-time sand mold, using the example of researching the thermal field of the cast part made of carbon steel with 0.25% C, hollow cylindrical shape, with the wall thickness of 100 mm. The developed analytical method for researching the thermal fields of cast parts is the analytical basis for the refinement of applied computer programs for modeling crystallization and cooling processes in foundry production.