Modelling of technological process of joining steel ropes with the use of powder antifriction material and a conductor

When determining the causes of structural defects of a steel rope, the technology of carrying out work on splicing by a team of specialists was studied in detail. Field observations and experimental studies, as well as mathematical modeling of the process of structural defects formation in the rope joint section, allowed to establish that the cause is the imperfection of the existing technology for performing splice work [1-5]. The existing technology directly depends on the experience (professionalism) of a splicing team and provides for the work on splicing, as a solution to a new problem for every hawser, expressed in the design and calculation of the main parameters, according to the established standards of the rope manufacturer. It is noted that this labor function negatively affects a person, causing dangerous and harmful factors of the working environment, such as: severity and intensity of the labor process. Under the influence of dangerous and harmful factors, the specialist is subject to: static and dynamic overload, mental overstrain, neuropsychiatric overload, which negatively affect a person and, as a result, affect the quality of the work performed as a whole. The total accumulation of dangerous factors in the course of work leads to the decrease in the quality of the obtained results and deviation from the normalized indicators, which is unacceptable and leads to the formation of structural defects of a steel rope.

Investigation of Barkhausen Noise Emission in Steel Wires Subjected to Different Surface Treatments

Steel rope wires represent the main bearing components of bridges whose long-term operation depends on loading conditions, corrosion attack, and/or pre-stressing. Corrosion attack especially can remarkably reduce the effective cross-sectional area, which in turn over-stresses the wires and redistributes stress to the neighboring wires. The premature collapse of many bridges is very often caused by wire rupture as a result of their poor corrosion protection. For these reasons, various processes—such as galvanizing, phosphating, etc.—have been applied to steel wires to increase their resistance against corrosion. However, these processes can alter the microstructure, especially in the near-surface regions. The Barkhausen noise technique has been already reported as a suitable technique for investigating corrosion extent and true pre-stress in the steel rope wires. This study reports that non-homogeneity of the surface state of wires undergoing different surface treatment makes it more difficult to assess the true stress state and increase the uncertainty of Barkhausen noise measurement. Barkhausen noise signals are correlated with metallographic and SEM observations as well as microhardness measurements. The non-homogeneity of the surface state of wires is also investigated by the use of chemical mapping and linear chemical analyses.

Approaches to taking into account horizontal movements of foundations in the work of wooden reinforced cables

The behavior of a wooden stress ribbon structures reinforced with steel rope under the action of a load evenly distributed along the entire length of the cable was investigated. The analysis of the results of static tests of the wooden reinforced cable of the VD-3.1 series is given. A criterion is proposed according to which a wooden stress ribbon structures reinforced with steel rope can be considered according to the theory of rigid threads. To ensure the stability and geometric invariance of the structures formed by rigid threads, an important role is played by taking into account the pliability of the supports that perceive the horizontal support reactions (spacing of the cable). Deformation of the supports of rigid cables causes the appearance of significant bending moments in the body of the cable, and also leads to an increase in the deflection of the structure. Therefore, special attention was paid to the study of the pliability of supports during the tests of wooden stress ribbon structures reinforced with steel rope to the action of a load evenly distributed along the length of the cable. The pliability of supports during experimental tests of wooden stress ribbon structures reinforced with steel rope was investigated. The obtained results are compared with the calculated value of the pliability of the supports, calculated based on the deformability of the installation for testing cable structures. The methods of calculating the deflections of the cables, which take into account the pliability of the supports, were tested. The influence of the pliability of the supports on the deflection of the cable is determined. At the level of the pliability of the supports, the deformability of the cable was influenced by the pliability of the nodal joints of the wooden elements of the cable. Based on this, the deformability of the joints of the wooden elements of the cable on the punched metal plate fasteners and its effect on the deflection of the cable were investigated. The coefficient of deformability of joints was suggested, which took into account the nonlinear dependence of the deformation of joints of wooden elements of the cable on the applied load. Due to the need to take into account the joint work of the wooden body of the cable and the steel rope, the calculated characteristics of the reduced cross section of the wooden cable reinforced with steel rope were calculated. A static calculation of a wooden stress ribbon structures reinforced with steel rope according to the theory of rigid threads is performed and the results of calculations are compared with experimental data.

О возможности использования канатных опор «mamsar» в качестве отдельных или сборных муфт и устройства для определения их жесткости

В статье подчеркивается важность муфт являющиеся как весьма ответственных узлов, входящих во многие механизмы и машины, часто определяющих их надежность и долговечность. Наиболее ценными в статье являются: 1. Выдвинутая гипотеза о возможности использования нетрадиционных стальных канатных виброизолирующих опор в качестве как отдельных, так и сборных виброизолирующих муфт приводов на основе опыта разработки, создания и применения на различных объектах техники опор MAMSAR . На основе конструктивного обзора и анализа широкого спектра канатных виброизолирующих опор MAMSAR , в статье представлены некоторые наиболее простые их конструкции в качестве муфт. 2. Представленные оригинальные устройства MAMSAR для определения жесткости соответствующих канатных муфт. 3. Практически реализованные канатные муфты и устройства для статических испытаний. 4. Подтверждение выдвинутой гипотезы о возможности использования нетрадиционных стальных канатных виброизолирующих опор в качестве как отдельных, так и сборных виброизолирующих муфт приводов.The article emphasizes the importance of couplings as very important components that are included in many mechanisms and machines, often determining their reliability and durability. The most valuable in the article are: 1. The proposed hypothesis about the possibility of using non-traditional steel rope vibration-isolating supports as both separate and prefabricated vibration-isolating drive clutches based on the experience of developing, creating and using MAMSAR supports at various facilities. Based on a constructive review and analysis of A wide range of mamsar cable vibration-isolating supports, the article presents some of their simplest designs as couplings. 2. Presented original devices MAMSAR for determining the stiffness of the corresponding rope couplings. 3. Practically implemented rope couplings and devices for static testing. 4. Confirmation of the proposed hypothesis about the possibility of using non-traditional steel rope vibration-isolating supports as both separate and prefabricated vibration-isolating drive clutches.

REASURCH THE WORK OF THE TRADITIONAL CIRCULAR ARCH OF TIMBER JAMBS WITH AN OPTION OF ITS STRENGTHENING

The article discussesthe research of the traditional circular archs of timber jambs, designedin the 16-th century by the French architectPhilibert Delorme, with an option of its strengthening, which make this arch comparable to the glued timber one. The experimental research of a flat arch, made of small wooden bricks strung on a steel rope and prestressed from the foundationzone, was carried out in the NRU MGSU. According to the results, it was found, that the arch has a low carrying capacity and can work only on compression. However, by strengthening the arch by using a steel band along its upper face and thus moving to the truss structure, it is possible to increase significantly its carrying capacity and bring it closer to the glued timber arch. During tests, it was noted that by the character of its work this arch is close to the circular arch of timber jambs. In the LIRA-CAD PC a computer simulationwas carried out of the traditional and the strengthened by a steel band along its upper face circular arches of timber jambs, as well as the glued timber arch. The following results were obtained.During the deformation process, the deflection of the strengthened circular arch decreased by 31%, and the stresses in it decreased by 26% compared to the traditional one, and according to the carrying capacity the arch has become comparable to the glued timber one. On this basis the conclusions were obtained, that it is possible to create non-linear form constructions, inherent to the natural objects, using the strengthened circular arch.

Theoretical foundations of modeling the process of transport vehicles steel ropes structural defects formation

The article presents materials on the study of mathematical modeling of splicing (binding) of steel rope used to transmit traction by friction. The developed mathematical model splicing (binding) describes the stress-strain state of strands (wires) from quasistatic loads, arising in the cyclic tension process and bending of steel rope on rope sheave, in which the resultant force in steel rope cross section is shifted relative to the central axis, causing it to bend and torsion. Using experimental data, it was found that the steel rope torsion and bending is caused by the linking technology in the nodes where strands are replaced. Experimentally established, that defects on the splicing (binding) site manifested as a result of cyclic tensile and bending loads on rope sheave, which is connected to limited mobility of the strands in nodes due to cross section symmetry violation.