Papers by Keyword: Deformation

Abstract: Gear hones are used as tools for gear honing. The efficiency of using gear hones mainly depends on the parameters of their compound material, first of all on the wear resistance and elasticity modulus. In terms of the elasticity modulus, gear hones can be hard and elastic, depending on the bonding agent type. Experience shows that gear-hone teeth distort during gear honing; they feature contact and flexural deformation and wear during metal removal, including along the tooth space. For this reason, it is necessary to consider the deformation and wear values for designing of gear hone geometry. An approach for calculation of variable engagement parameters, using a geometrical model in the form of sliding trapezoids to consider the dimensional wear of gear-hone teeth based on the positive correlation factor of the original profile. Such designing of gear-hone teeth provides sufficient thickness in the original section, which ensures high performance capacity of gear-honing tools and required workability.

Abstract: Polymer coatings are increasingly used in mechanical engineering. In particular, sheet composite elements are created on their basis. But the question of the influence of vibration loads on the bearing capacity of composite structures remains relevant. This work presents the results of an experimental study of the operation of composite structures when exposed to vibration loads. The choice of the parameters of the test bench is due to the frequencies of natural vibrations of the specimens under study. The frequencies were determined using generally accepted approximations. A test bench was developed for carrying out measurements. A vibration-absorbing foundation was used, a support frame with the element was attached on elastic suspensions to the outer frame. A scheme for cutting sheet elements for tensile testing was developed. Nine sheet elements made of reinforced polymer material were tested. The influence of the number of loading cycles on the material ultimate strength is investigated. It was established that the presence of a reinforced polymer coating leads to a decrease in the vibration amplitude when approaching the resonance frequencies. This is due to the internal deformation of the polymer coating. After removing the vibration load, no cracks were found on the specimens.

Abstract: It is proposed a mathematical model of a metamaterial which is represented as a nonlinear elastic two-mass chain with a center of symmetry. The model was continualized. The conditions for the formation of non-sinusoidal strain waves are analyzed.

Abstract: The paper presents the results of metallographic and electrophysical studies of the structure of 12X18H10T steel after plastic deformation. Studies allow us to determine the optimal modes of plastic deformation of corrosion-resistant steels.

Abstract: In this study, the process of high-velocity impact welding of commercially pure Al and Ti plates was simulated using smoothed particle hydrodynamics (SPH) method. The paper aimed to determine by numerical simulation the range of collision parameters suitable for Al and Ti welding, and to compare the results obtained with the known semi-empirical models used to construct the "weldability window". For this, a set of simulations with different collision point velocity and collision angle was carried out. From the data obtained, it follows that SPH simulation reproduces well the shape of the interface, typical for high-velocity impact welding, and provides better understanding of material flow and related phenomena. This method allows one to select the collision parameters that are optimal for a high-quality joint.

Abstract: In this paper, we consider the effect of cold rolling and hydrogen alloying on the formation of twin boundaries of the corrosion resistance of austenitic steel 01Cr17Ni13Mo3. Using the method of transmission electronic microscopy, microdiffraction patterns were obtained. The analysis of microdiffraction patterns indicates the formation of a developed grain-subgrain structure with small-angle and large-angle misorientation. The structure has a high dislocation density, deformation twins and localized shift bands. It was established that plastic deformation by flat rolling to ε = 90 % at room temperature does not contribute to the appearance of a noticeable amount of α' and ε-martensite. At the temperature of liquid nitrogen, the samples were found to form a small fraction of the α'-martensite phase. Such a small amount of martensite can contribute to steel strengthening, and a decrease in the rolling temperature will lead to an increase in the strength properties of steel. It was detected that the density of twin boundaries under the decrease in the rolling temperature but with the same intensity of hydrogen saturation is significantly higher. A noticeable reduction in the width of the twin lamellas was revealed.

Abstract: The influence of various concentrations of the selected phosphorus-containing stabilizers on the properties of stabilized and unstabilized polyetheretherketone has been investigated by the methods of spectroscopic, thermal and physical-mechanical analysis. The most effective stabilizer was determined, the positive effect of certain concentrations of phosphorus-containing stabilizers on the thermal stability of polyetheretherketone was revealed.

Abstract: The quenching is one of the most used mechanisms for increase the strength of aluminium alloys sheets. The purpose of quenching is to keep the super-saturated solid solution formed during the solution heat treatment as intact by rapid cooling. In order to establish the influence of the addition of polymer in the quenching water on the distortion and residual stresses of the aluminium alloy sheets, several tests were performed with different concentrations of the polymer in demineralized water. The experiments were performed on 6082 aluminium alloy sheets with a thickness of 5 mm. The quenching of the samples was done by immersion in a stainless steel vessel with a capacity of 10 liters. The obtained results show that the addition of polymer in demineralized water positively influences the deformation of aluminium alloy sheets. In this way, a correlation between the polymer concentration and the deformation of the plates was established. Regarding the internal stresses, no correlation was identified with the level of polymer used in demineralized water.

Abstract: The relationship between the elastic-plastic properties of concrete and its ability to resist the external loads and internal stresses effects arising under the influence of aggressive environmental factors has been studied. In concrete, micro-and macrocracks are filled with air and a liquid phase migrates with periodic environmental temperature, therefore, humidity changes. When the structure is compacted by crystalline hydrate neoplasms arising from supersaturated solutions, their surface increases and, correspondingly the part of water hydraulically bound to it also increases which changes its mobility with temperature. This entire system of interphase and single-phase structural bonds and interactions in concrete changes with fluctuations in humidity, cooling, and especially during phase transitions during freezing. The research found that the introduction of hydraulic additives into the binder, which carry a negative charge on their surface, leads to a charge change of the material structure pore space. The penetration kinetics of aggressive environments, adsorption interaction with the cement stone capillaries surface has been studied.

Abstract: In the forging industry, rolling is used to produce ring forgings, which are widely used in power and nuclear engineering. According to the technical conditions and established practice, large ring forgings are made using the operations of precipitation, piercing and rolling out with a striker on the mandrel.