SIMULATION OF DOOR MOVEMENT WITH A CLOSING MECHANISM

The work objective is to determine the parameters of the closing mechanism that provide the specified characteristics of the door movement. Research method: computer simulation of the movement of a door with a lock mechanism as a multi-mass dynamic system, taking into account the mechanical characteristics and contact interaction of the lock mechanism. Research results and novelty. Computer dynamic models of a door with a door closer and a door with a spring have been developed. The moments of the door opening force, the closing time of the door, the angular velocity of the door at the time of impact with the frame are considered as the criteria for the quality of the door closing mechanism. Formulas are obtained that determine the permissible values of stiffness and deformation of the door closer spring according to the specified moments of the door opening force. The movement of doors with a door closer and with a spring is compared. The parameters of the closing mechanism providing the specified characteristics of the door movement of the considered example are determined. It is shown that with the same values of the opening force moments, the speed of impact with the frame in the case of the door closer is less than the door with a spring. Conclusions: The developed computer dynamic models of a door with a door closer and a door with a spring make it possible to determine the characteristics of the door movement taking into account the inertial and mechanical characteristics of the door closer and spring mechanisms. The permissible values of stiffness and deformation of the door closer spring can be determined by the specified moments of the door opening force in two positions. It is established that the forces of air resistance and friction in the hinges of the door cannot create the moment of resistance necessary for smooth closing of the door without a strong impact on the frame with a limited closing time. The quality criteria that minimize the closing time and the speed of impact of the door with the frame are contradictory. The choice of optimal parameters of the door closing mechanism is possible if one of the criteria is replaced by a restriction. The developed formulas and computer models are recommended for use in the design of devices that restrict the movement of doors.

Experimental Analysis of the Influence of the Application of TiN, TiAlN, CrN and DLC1 Coatings on the Friction Losses in an Aviation Internal Combustion Engine Intended for the Propulsion of Ultralight Aircraft

Currently, there are many methods of reducing the friction losses of the main components of an internal combustion piston engine. The operating conditions of internal combustion piston engines intended for the propulsion of ultralight aircraft differ significantly from those prevailing in the case of using these engines for the propulsion of vehicles. There are many studies on the influence of selected anti-wear coatings on the friction coefficients when using various lubricants, measured via tribometers. Unfortunately, the conditions obtained in the laboratory significantly differ from those prevailing in an engine operating under external conditions. The study investigated the influence of a change in the tribological parameters of TiN, TiAlN, CrN and DLC1 anti-wear coatings on the moment of resistance to the piston movement of an aircraft engine. The operating parameters of a real engine working in an aircraft were simulated. The main focus was on the coating layers of the sliding surfaces of the piston rings and the cylinder running surface. The properties of the coatings affect the correlation of the scale of the adhesion and cohesion phenomena of the oil to the opposite planes, and this determines the nature of the changes in the moment of resistance to engine motion. As it is commonly known, with an increase in the value of the maximum pressure of the working medium in the combustion chamber, the share of mixed friction in liquid friction increases, similar to the high oil temperatures occurring in aircraft engines. Therefore, there is a justified need to supplement the research in the field of analyzing the characteristics of the torque of resistance to motion for these engines, in particular in the field of the usable rotational speeds of the crankshaft. Applicable anti-wear systems based on selected coatings can significantly improve operational safety and noticeably reduce fuel consumption.

Method for investigating rarefied gas flow around a cylindrical surface at arbitrary Knudsen numbers

A moment method for solving the linearized kinetic Boltzmann equation for arbitrary Knudsen numbers is presented. The isothermal flow of a rarefied gas around a cylindrical surface (the limiting cylindrical Couette problem) is investigated. The moments of the collision integral are calculated for the hard sphere model. The moment of resistance force acting per unit length of the surface, the profile of the gas flow velocity in the transient regime, and the gas velocity on the surface are calculated.

Estimating marine engine efficiency in dynamic processes

The article considers the problem of efficiency of energy objects, which is mainly estimated on the basis of their static characteristics. If dynamic processes take up a significant part of the object's time and budget, then there is a need for additional account of energy losses in transient processes. Using the analysis results it is necessary to select the settings of the object regulators. The problem hasn’t been thrown much light on in the publications. An attempt has been made to estimate the additional energy losses of the main engine operating on the propeller of a transport ship. To analyze the transient process of the dependence of the rotation speed on time, it is assumed that this process is caused by a sharp change in the moment of resistance by a given value. The Excel program was proposed to assess the dependence of the rotation speed on time. 10% of the nominal value of the setting or disturbing influences was chosen as the change leading out of the static equilibrium. To compare various transient processes it is proposed to use the value of the length of the transient process in time. Assessing energy losses was carried out by using the coefficient of increasing power consumption during the transient process. The additional energy losses were proved to make more than 1.0 - 1.5% of the nominal power of the controlled object due to the presence of transient processes at 10% disturbance. By changing the settings of the automatic control system (ACS) these losses can be reduced. It has been found that adjusting the ACS settings to reduce energy losses under disturbing influences leads to the higher energy losses during reference influences.

CHANGES IN THE CODE OF RULES FOR THE DESIGN OF STRUCTURES MADE OF CONCRETE WITH POLYMER COMPOSITE REINFORCEMENT

The article presents information about the changes made to the code of rules for the design of concrete structures reinforced with polymer composite reinforcement. New rules for the formation of relative deformations at the base point of a two-line diagram of concrete under axial tension, used to calculate reinforced concrete elements for the second group of limit states, are described. The rules for calculating re-reinforced structures of T-or I-beam cross-sections with a shelf in a compressed zone by the method of limiting forces are presented. The rules for taking into account the inelastic properties of concrete of the stretched zone when determining the elastic- plastic moment of resistance for the extreme stretched fibre of concrete with a rectangular cross-section and a T-shape with a shelf located in the compressed zone are clarified.

Seismic Analysis of Multi Storey Building Using Strong Column Weak Beam Ratio (SCWB) in Different Zones of India

An earthquake structures are mandatory to avoid significant damages (i.e., collapse) and aims that structure withstand a major earthquake without collapse. The design approach adopted is to ensure that the columns of the structure more capable to resist moments than beam; to avoid progressive collapse of structure due to failure of columns in lower level; it is necessary the columns have stronger than beams (strong column weak beam). The concept of SCWB is to ensure that plastic hinge formed in the beam not in the column; this help in dissipating the more energy along with providing ductility to the structure. If the plastic hinge is formed on the both ends of column then, the column is not able to spread the plasticity and collapse which are leads to global failure. The failure modes in all past earthquake is exactly opposite i.e, strong beam weak column; and comes to sway mechanism and fails to collapse. For this it is foreseen that the values of ratio of Mc/Mb (ratio of sum of ultimate moment of resistance of columns to sum of ultimate moment of resistance of beam) in the beam-column joint are stated by many design codes and the values are different ranging from 1.2,1.3,1.4,1.5 to 2, etc. Another effect of ratio Ic/Ib (ratio of moment of inertia of column to moment of inertia of beam) have been studied but the exact meeting of SCWB behaviour in the structures at the time of collapse not stated clearly. The Mc/Mb and Ic/Ib ratio are very important to prevent damage in the structure under seismic action. In the present work, attempts are made to achieve exact ratio of exact strong column weak beam. In this study, the combined effect of two ratio (Mc/Mb, Ic/Ib) simultaneously investigated in different zones of India to find out exact SCWB ratio’s value for to meet the SCWB behaviour. Different numerical examples are presented of combine ratios (Mc/Mb,Ic/Ib) and pushover analysis is performed on each ratio’s. The result of the investigation highlighted on the objective that is to find exact SCWB ratio value considering the parameter like target displacement, ductility ratio, hinge response etc.

DETERMINATION OF THE DYNAMIC TORQUE OF THE RESISTANCE OF THE DRIVE SHAFT OF THE REPLACING MACHINE FORMED BY THE MOVEMENT OF THE BULK ENVIRONMENT IN THE WORK TANK

Galvanizing technological operations include the processes of cleaning the surfaces of parts from burrs, burrs, bumps and scale, corrosion products, rounding of sharp edges, separation of parts from castings, as well as processes to improve the quality of product surfaces: grinding or polishing. These technological operations are implemented using different types of equipment: vibrating, rotary and spindle machines, rotating drums, etc. The most promising are considered to be machines with complex spatial movement of working tanks. Analytical researches of definition of dynamic moment of resistance of a driving shaft of the shredding machine on the basis of laws of movement of loose mass in the middle of working capacity are carried out. The positions of the moving parts of the machine and the bulk array in the middle of the tank, which correspond to the maximum dynamic component of the moment of resistance on the drive shaft created by the bulk array loaded to the working tank. An expression is obtained to calculate the value of the dynamic component of the moment of resistance on the drive shaft of the machine, created by the bulk array loaded to the working tank. The obtained research results can be used by the relevant machine-building enterprises at the stage of designing galvanizing types of equipment with tanks performing complex spatial motion.

DETERMINATION OF THE STATIC MOMENT OF THE RESISTANCE OF THE DRIVE SHAFT OF THE REPLACING MACHINE, CREATED BY THE MASS OF THE BULK ENVIRONMENT IN THE WORK TANK

Among the different types of shredding equipment, which is widely used in various industries of Ukraine, the most promising are machines with complex spatial movement of working tanks. Experimental studies of the movement of the bulk array in the middle of the working tank with transparent walls were performed. The positions of the moving links and the working capacity are set, at which the whole bulk array by its mass will create the greatest value of the static moment of resistance on the driving shaft of the machine. Analytical studies of the static moment of resistance formed on the drive shaft of the machine with complex spatial motion of the working tank as a result of the influence of gravity acting on the bulk array loaded into the tank, the corresponding mathematical dependences are obtained. The obtained research results will be useful in further determining the dynamic moment of resistance on the drive shaft, which will be created by moving the moving parts of the machine and the bulk array in the middle of the tank. Also, the results of research can be used by relevant machine-building enterprises at the stage of designing galvanizing types of equipment with tanks that perform complex spatial movement.

NEW CENTRAL NODE OF THE UPPER BELT OF THE PITCHED TRUSS

Постановка задачи. В скатных фермах из стальных тонкостенных холодногнутых и стеклопластиковых профилей, где элементы соединяются непосредственно на болтах с помощью листовых фасонок, основной проблемой является недостаточная жесткость центрального узла верхнего пояса, что существенно влияет на устойчивость фермы в процессе транспортировки, монтажа и ее эксплуатации. В связи с этим предлагается рассмотреть новое узловое соединение верхнего пояса двускатной фермы. Результаты. Установлено, что предлагаемое новое решение центрального узла верхнего пояса скатной фермы позволяет повысить жесткость узла из плоскости. Отмечается, что конструктивное решение может найти применение при изготовлении решетчатых конструкций из стальных тонкостенных холодногнутых и стеклопластиковых профилей. Выводы. Рассмотрено новое узловое соединение центрального узла верхнего пояса двускатной фермы. Доказано, что решение позволяет увеличить момент сопротивления сечения из плоскости. Узловое соединение обеспечивает устойчивость из плоскости фермы на стадии транспортировки, монтажа и ее эксплуатации. Statement of the problem. In pitched trusses made of steel thin-walled cold-formed and fiberglass plastic profiles, where the elements are connected directly on bolts using sheet gusset, the main problem is the lack of rigidity of the central node of the upper belt, which significantly affects the stability of the farm during installation and operation. Therefore, it is suggested that a new node connection of the upper belt of the pitched truss is considered. Results. It is established that the suggested new solution of the central node of the upper belt of the pitched truss allows the rigidity of the node to be increased. It is noted that the structural solution can be employed in manufacturing lattice structures of steel thin-walled cold-formed and fiberglass plastic profiles. Conclusions. The new node connection of the central node of the upper belt of the pitched truss is considered, it is proved that the solution enables an increase in the moment of resistance of the section from the plane. The node connection allows stability to be provided from the plane of the truss at the stage of installation and its operation.

Dynamics of the hydraulic fluid power of rotation of the hose concrete pump

Purpose. Search for ways to improve the technical level of the hydraulic fluid power of a hose concrete pump by analyzing the hydraulic schematic diagram and dynamic characteristics depending on the moment of resistance, moment of inertia and properties of the working fluid. Method. The construction of a mathematical model of the dynamics of a hydraulic fluid power is based on Newton's laws of mechanics, Pascal's law and the continuity equation for fluids. The dynamics study was implemented using the VisSim package. The results of studies of the influence of variable parameters on the rotor speed and pressure in the discharge line of the hydraulic motor are presented in graphical form. Results. It was found that in a volumetric hydraulic fluid power of a concrete pump with rotor rotation from a gerotor hydraulic motor, there are significant fluctuations in pressure and speed, due to the kinematics of the pump, temporary factors of the increase in the moment of resistance and supply of the working fluid to the hydraulic motor with the throttle method of its regulation. The ratio of the maximum and steady-state pressure values is 1,9 times obtained for hydraulic motors of different displacement. The possibilities of reducing the dynamic loading of the hydraulic fluid power by improving its hydraulic schematic diagram and control algorithm are shown. Conclusion. Recommendations have been developed for reducing dynamic loads in a hydraulic fluid power by modernizing the hydraulic circuit diagram by introducing electrohydroautomatics devices and changing the algorithm for starting and stopping the pump.