• MECHANIZATION IN AGRICULTURE

    Study of the oscillation processes of a front-mounted haulm harvester when it moves on the inequalities of the ground surface

    Mechanization in agriculture & Conserving of the resources, Vol. 66 (2022), Issue 3, pg(s) 86-90

    In the article the calculated mathematical model of oscillations of the haulm-harvesting machine frontally attached to a wheeled tractor is constructed. A nonlinear differential equation is obtained, which describes the oscillations of a haulm-harvesting machine in the longitudinal-vertical plane during the movement of its pneumatic copying wheels along the unevenness of the soil surface. On the basis of the received theoretical results rational constructive and kinematic parameters of the front-mounted hoisting machine which provide decrease in amplitude of the specified fluctuations are defined. So, at translational speed of movement of the haulm-harvesting unit V = 3.0 m∙s–1, the amplitude of oscillations of the rotor of the haulm harvester decreases in 1.2…1.5 times in comparison with height of roughnesses of a surface of the field o h = ± 0.04 m. At the amplitude of oscillations of the lower ends of the knives of the rotary cutting device up to 4 cm, the loss of the tip does not increase significantly. However, when increasing the values of the amplitude of these oscillations to 7 cm or more, the loss of the branch increases significantly and the maximum values of which exceed 12%.

  • MACHINES

    Influence of trolley motion in the dynamic behavior of semi-portal cranes

    Machines. Technologies. Materials., Vol. 15 (2021), Issue 5, pg(s) 170-175

    The paper presents dynamic analysis of the Semi-Portal Cranes for the case of Trolley motion travelling on Crane’s Girders. Semi-portal cranes are mainly mounted in the industrial facilities, and they consist of metallic structures with big dimensions and many mechanisms that carry heavy loads. We will analyze the influence of the Trolley motion in the dynamic behavior of Semi-Portal Crane while carrying maximum Load, in particular the influence of Load swinging and oscillations. The method of analysis is acquiring experimental measurements and comparing those results with the results gained through modeling of crane, and carrying simulations. Designing the Crane’s 3D model with software and motion simulations is the method applied in the paper to analyze dynamics and is important to explain the form and intensity of oscillations that can cause accidents, failures of parts, and other concerns about the safety. Analysis will be done for maximal and minimal speed of the Trolley. Conclusions from this paper will be useful about the design, dynamic response and safety of Semi-Portal Cranes. The analysis will be focused to find main kinematic and dynamic parameters influencing the crane dynamics, like forces, moments, speed (velocity), and Load swinging magnitude. The Crane is modeled based on the Data from standard manufacturer of Semi-Portal Cranes.

  • MECHANIZATION IN AGRICULTURE

    Theory of vertical oscillations of a frontally mounted tops harvesting machine

    Mechanization in agriculture & Conserving of the resources, Vol. 67 (2021), Issue 2, pg(s) 41-46

    To establish influence of kinematic and constructive parameters of tops-harvesting machine on quality of a continuous cut of the massif of tops at oscillations in the longitudinal-vertical plane of its tops-cutting device at frontally mounted machine on a wheeled row-crop aggregate tractor. Used modeling methods based on higher mathematics, theoretical mechanics, solving a system of differential equations and compiling programs and numerical solutions on a PC. An equivalent scheme has been developed for a tops-harvester mounted on a wheeled tractor in front of it on its oscillations in the longitudinal-vertical plane, considering all the forces that arise, taking into account the kinematic excitation that occurs when moving along soil surface definitions also due to the elastic-damping properties of its support-copying wheels. For the specified equivalent scheme, on the basis of application of initial equations in the form of Lagrange of the 2nd kind, on the chosen generalized coordinates, the system of two nonlinear differential equations of oscillatory motion of the tops-harvesting machine is received. According to the analytical transformations, the solution of this system was obtained, which made it possible to obtain the f inal expressions for determining the amplitude and circular frequency of natural and forced oscillations of the tops-harvesting machine. Numerical calculations of the received expressions on the made program on the personal computer are carried out . According to the results of numerical simulation, the final expression was obtained, which allowed to determine the vertical displacements of the end of the rotary cutting unit during the oscillations of the topping machine in the longitudinal-vertical plane. Numerical calculations on the PC of the received expression gave the chance to construct graphic dependences which establish dependences of amplitude of the specified oscillations depending on constructive parameters of the tops-harvesting machine, and also characteristics of roughnesses of a soil surface and elasticdamping properties of copying wheels.

  • MECHANIZATION IN AGRICULTURE

    Mathematical model of root head cleaning machine with vertical drive shaft

    Mechanization in agriculture & Conserving of the resources, Vol. 67 (2021), Issue 1, pg(s) 3-6

    The operation of the machine attached to the back of the tractor to clean the heads of root crops from residues in the case of using copying pneumatic wheels causes oscillations of the tops harvester in the vertical plane, which significantly affects the quality of the process. Accordingly, the movement of the horizontal working body will depend on many structural and kinematic factors. Therefore, the development of a mathematical model that will describe the movement of the working body of such a unit is an important task. To solve which the method of construction of calculated mathematical models of functioning of agricultural machines and machine units, on the basis of theoretical mechanics and higher mathematics was used in the work.. Using which the equivalent scheme of movement of the unit is developed and the system of two nonlinear differential equations for detailed research of oscillations of the cleaner of heads of root crops in the longitudinalvertical plane at movement of its pneumatic copying wheels on roughnesses of a surface of soil is received. The mathematical model of movement of the cleaner with a horizontal cleaning shaft developed on the basis of initial equations of dynamics in the form of Lagrange of the 2nd kind allowed to establish depedencies between constructive and kinematic parameters of the car and its oscillatory characteristics. The found dependences created preconditions for the further mathematical modeling of parameters of the rear-mounted cleaner of heads of root crops, with a horizontal clearing shaft. Using the developed calculation model it is possible to optimize the values of angle B and coordinates у that characterize the oscillations of the machine in the longitudinal-vertical plane.

  • TRANSPORT TECHNICS. INVESTIGATION OF ELEMENTS. RELIABILITY

    Scissor lift dynamic analysis and motion regulation for the case of lifting with maximum load

    Trans Motauto World, Vol. 6 (2021), Issue 2, pg(s) 38-42

    This paper deals with Dynamic analysis of Scissor Lifts during the Load Lifting to determine their dynamic behavior, find the nature of oscillations, and the regulation of lifting to minimize these oscillations and optimize the work process. During the motion processes, the lift and its main parts undergo heavy forces, moments, and oscillations. The method of research is acquiring results through design, modeling, and simulations, comparing them with analytic calculations, and looking for the optimal motion regulation of the Load Lifting. The analysis will be acquired when the Scissor lift is carrying maximum Load. The study will be concentrated in the finding the nature of dynamic forces and stresses that acts on the main parts of the lift and the extent and the form of oscillations. Results will be shown in the form of diagrams and contour views as the solution results of the tested system. Modeling and simulations will be carried using software SimWise 4D, based on the type of the Scissor Lift taken from Standard Manufacturer. Conclusions of these analyses are useful for design considerations, dynamic behavior, and safety of these types of lifts.

  • DYNAMIC ANALYSIS OF BRIDGE CRANE WITH ONE MAIN GIRDER DURING TELPHER MOTION WITH FULL LOADING

    Machines. Technologies. Materials., Vol. 12 (2018), Issue 8, pg(s) 305-308

    This paper deals with dynamic analysis of bridge crane with one main girder during telpher motion in order to determine dynamic behavior and oscillations while carrying full load. During the telpher motion the main girders and side girders are heavy loaded parts while they undergo forces, moments and oscillations from lifting mechanism that carries workload. The method of analysis is the comparison of results gained through modeling and simulation and experimental measurements. The analysis will be concentrated in finding the nature of dynamic forces, moments and stresses that acts on main crane’s parts and finding the extent and form of oscillations that can cause damage and failures. Also the interest is to study the effects of load swinging in crane’s stability. Results will be shown in the form of diagrams as the solution results of the tested system. Crane is modeled from standard manufacturer, as a special type of Bridge Crane with one main girder and telpher. Conclusions of these analyses are useful for design considerations, dynamic behavior and safety.

  • TRANSPORT TECHNICS. INVESTIGATION OF ELEMENTS. RELIABILITY

    INTERACTION BETWEEN ROLLING STOCK AND RAILWAY TRACK WITH OF THE ELASTIC PROPERTIES OF THE BASE

    Trans Motauto World, Vol. 3 (2018), Issue 3, pg(s) 113-115

    The main trend in considering the interaction of the railway track and the rolling stock is the studying of the parameters of the rigidity of the interaction. For the study, a model of the track design, described using the basic concepts of the theory of elasticity and the propagation of elastic waves was developed. The study of the peculiarities of the interaction of the rolling stock and the track, taking into account the elastic properties of the base, allows to expand the possibilities of solving the problems of ensuring their functionally safe operation with a certain level of operational efficiency.

  • TRANSPORT TECHNICS. INVESTIGATION OF ELEMENTS. RELIABILITY

    REDUCING THE DYNAMIC LOAD OF MECHANICAL WATER-JET DRIVE OF AMPHIBIOUS MACHINES

    Trans Motauto World, Vol. 2 (2017), Issue 2, pg(s) 51-53

    The article provides an analysis of the excitation conditions and the results of the detuning of parametric resonance in mechanical drive amphibious water-jet machines. The paper substantiates the possibility of solving the problem of reducing the dynamic load on the basis of the synthesis filter low-frequency vibrations.

  • SUBHARMONIC RESONANCES IN THE HYDROMECHANICAL TRANSMISSION OF THE WHEELED CHASSIS

    Trans Motauto World, Vol. 1 (2016), Issue 2, pg(s) 31-35

    In the article on the basis of the developed mathematical model the dynamics of the highly nonlinear system is investigated, consistent patterns of resonant mode occurrences are established, which is experimentally confirmed. It is established that one of the main reasons for high dynamic loading and HMT elements durability reduction is subharmonic resonances caused by close agreement of frequencies of free nonlinear system fluctuations with multiple value of frequencies of diesel engine disturbances. On the basis of the new consistent patterns, the area of stability and parameter move direction is defined for its provision. The offered damper design is synthesized for significantly reducing HMT dynamic loading.

  • MACHINES

    MATERIAL DEFORMATION ANALYSIS IN BRIDGE CRANE DURING TRAVEL MOTION WITH FULL LOADING

    Machines. Technologies. Materials., Vol. 11 (2017), Issue 8, pg(s) 389-392

    This paper deals with dynamic analysis of bridge crane with single girder in order to determine material deformations in their main parts – cables and girder’s, while moving and carrying load. It is known that these are mostly loaded parts in crane, while they accept forces, moments and oscillations from lifting mechanism and load. Analysis will be accomplished using computer modeling and simulations. Work process of crane in the study is forward travel motion. It is assumed that this motion process makes major impact in the deformations of lifting cables and girders due to stress, oscillations, and negative effect of load swinging. The analysis will be concentrated in finding the nature of oscillations that acts on crane and finding the extent and form of materials stress and deformations that can cause fatigue, failures and accidents. Question is whether acting loads exceed elasticity limits, or there are plasticity deformations which lead to permanent damages. Results will be shown in the form of diagrams, contour stress and strain in cables and girders. They will be compared with experimental measurements. Conclusions of these analyses can be useful for design considerations and safety.

  • MACHINES

    TRUCK MOUNTED CRANES DURING LOAD LIFTING – DYNAMIC ANALYSIS AND REGULATION USING MODELLING AND SIMULATIONS

    Machines. Technologies. Materials., Vol. 10 (2016), Issue 8, pg(s) 12-15

    Truck Mounted Cranes are used for load lifting and lowering, mainly in construction industry for materials handling. These cranes have complex structure with many parts and mechanisms with bars, linkages, actuators, cables, outriggers, etc. Using modeling and simulations with software we will analyze dynamics and oscillations in crane while lifting the maximal load, and methods of control of these oscillations in order to optimize the work process of truck crane. Dynamic parameters analyzed are: velocity, acceleration, angular velocity, forces and torques that act in main parts of crane, including load swinging. The study will be accomplished with design of block diagrams that represents crane model and motion, and gain results in form of diagrams containing main kinematic and dynamic parameters. Results of the tested system will be used to get conclusions about dynamic behavior of crane, and look for optimal motion control. Analysis will be done using modeling and simulations with software MapleSim, based on truck crane from standard manufacturer.

  • STUDYING ROTATIONAL MOTION OF LUFFING BOOM CRANES WITH MAXIMUM LOAD USING SIMULATIONS

    Machines. Technologies. Materials., Vol. 9 (2015), Issue 12, pg(s) 20-23

    Luffing Boom Cranes are type of cranes used for load carrying in building sites. They have complex structure with big dimensions and mechanisms. Their working usage is high. Main cycles of the work of Luffing Boom cranes are: lifting and lowering the working load, Boom luffing – upwards and downwards, rotation around vertical axes, and (if mobile type) translational movement forward and backwards. In this work, we are going to study the work of this crane while rotating with full loading. Study will be done using simulations with computer applications. The aim is to see the effects of dynamic forces and moments in the crane’s main parts – metal construction, cables, and constraints during rotational work cycle, particularly at the start and end of the rotation. Also interest is to study the effects of load swinging in crane’s stability. For this purpose, we modeled with software entire luffing boom crane. Crane is modeled from standard manufacturer, as a common model of luffing boom Crane.