No abstract

Mechanical models of a transport system “carriage - track” while crossing a joint irregularity are proposed. An investigation was conducted on the peculiarities of static, shock and dynamic interaction between the four-axle car and the track, considering tram wheelsets motion features over joint irregularity. A method to solve the equations of a mathematical model of static, shock and dynamic interaction is developed. Numerical analysis is used to determine deflections of the facing rail under the first sleeper for each phase of motion depending on motion phases, and car load and speed.

Purpose. To formalize the dependence of the eigenfrequencies of translational and torsional vibrations of the structural elements of the vibrating machine articulated by the connection node on their design parameters and mechanical characteristics, as well as regulatory requirements for vibration activity, strength and accuracy. To develop a method for selecting the design parameters of the elastic band element of the package, taking into account the specified values of the amplitude and frequency characteristics of the dynamic loads reproduced by the supporting structure and the coefficient of variation of the natural frequencies of translational and torsional vibrations. Methodology. The research is based on fundamental approaches of applied mechanics, machine dynamics and vibration reliability. Findings. The dependences of the eigenfrequencies of torsional vibrations of the body parts of the vibrating machine connected by the connection node on their design parameters and mechanical characteristics are obtained and analyzed. Vibrations around an axis orthogonal to the working direction of the node are considered. A comparative analysis of the natural frequencies of the node in the direction of the transmitted vibration and its circular vibrations from the design parameters and mechanical characteristics of the elastic band elements, their number in the package and the number of packages in the connection node is performed. Originality. It is in the fact that for the first time the dependences describing the natural frequencies of translational and torsional vibrations of the body parts of a vibrating machine, articulated by a package of elastic band elements, are obtained. Also the paradigm for the choice of design parameters and mechanical characteristics of the elastic band element of the package, which is based on the results of a comparative analysis of the eigenfrequencies of vibrations in the working and connected directions through their coefficient of variation is innovative. This made it possible to include the criterion of vibration reproduction accuracy, which is formalized through the coefficient of frequency variation, together with the criteria of strength and rigidity, in the methodology of synthesis of the structural scheme of the vibrating machine. Practical value. The proposed methodological solutions for the calculation and selection of design parameters and mechanical characteristics of tape elastic elements ensure the achievement of vibration activity indicators of articulated parts, as well as the ratio of natural vibration frequencies in the working and related directions at the level of the requirements of normative documents when upgrading existing machines and creating new modern equipment. As a result, the reliability, durability, safety, productivity and load-bearing capacity of machines, equipment and mechanisms of mining engineering, aviation, transport and space technology are increased.

Priority directions and events among basic industries of municipal electric transport is resource saving in a transport system of underground passage during his exploitation. First of all this problem must be decided by scientific accompaniment, id est on the stage of planning of details and knots of transport vehicles. One of the basic tasks decided on the stage of planning is an increase of bearing strength of details due to the analysis of their tensely-deformed state. The article is sanctified to the calculation of supply of carrying capacity of stringer of front carriage of subway at operating under the middle of the equipartition loading case-insensitive transversal forces. Priority of research theme is reasonable, an aim and tasks are set forth. Two going offer near the power calculation of bearing strength of stringer: calculation on the assumed tensions and on the maximum states. The resilient models of beams are examined in both cases. In case of calculation on the maximum state mechanics of origin of plastic hinges is first of all grounded in the places of the hard fixing of ends of beam. A beam saves the bearing strength still. At the further height of the external loading appearance of plastic hinge is justified even in the middle of beam with a simultaneous loss by the beam of bearing strength. For the design of behavior of beam in accordance with her descriptions, including on tensions and by the condition of loss of her bearing strength. The mathematical raising of task of calculation of bearing strength of stringer at the calculation of possible tensions and maximum state is examined case-insensitive transversal force. Bearing strength of stringer is analysed at a calculation on possible tensions and on the maximum state. The analysis of the got results allows to judge about efficiency of an offer mathematical model on the whole. Got equalizations for the maximally possible loading at a calculation on the maximum states and on possible tensions allows reliably to estimate bearing strength of stringer in both cases. The increase of bearing strength of beam at a calculation on the maximum state is thrice-repeated. Drawn conclusion about adequacy of analysis of bearing strength of stringer.

Mechanical models of "railroad car-track" transport system for each phase of motion are developed. Particularities of dynamic interaction between the four-axle car and the track are studied by considering four phases of motion over joint irregularity. Methods for solving differential equations of the discretecontinuous system fluctuation are developed. Numerical analysis is used to determine deflections of the trailing rail under the first sleeper for each phase of motion depending on motion phases, and car load and speed.