The paper is devoted to the development mathematical model of automatic rotary motion electrohydraulic drive for technological equipment and structural scheme of mathematical model for drive as object of automatic control. The hydraulic drive of rotary motion with volume regulation is considered. The drive contains regulated pump and unregulated hydraulic motor. The regulation of the working volume of the pump is carried out by the electrohydraulic amplifier. The transfer function of the regulating process of the pump working volume is represented by aperiodic link of the first order. The adequacy of mathematical model for dynamic characteristics of electrohydraulic drive has been confirmed experimentally by the Fisher criterion. To verify the adequacy, we compared the experimental and calculated transient processes for the shaft angular rotation velocity of hydraulic motor when applying the control signal. The mathematical model of automatic rotary motion electrohydraulic drive for technological equipment as object of automatic control was used as basis for further research on the synthesis of automatic control systems for equipment.
The formation of structure and properties of thermal coatings is largely determined by the transformation intensity of sprayed materials at all stages of obtaining of coating. It is shown that during D – gun spraying, in order to ensure optimal conditions for leading transformations and phenomena that have a decisive influence on structure and properties of sprayed coatings, composition of combustible mixture, geometry and dimensions of barrel, conditions for introducing powder into the barrel and a unit dose of powder, spraying distance, timing of spraying cycle and other technological methods can be used. The possibility of transformation in powders of tungsten carbide and chromium under different methods of thermal spraying is analyzed and the structure and properties of coatings are obtained. The influence of the conditions of D – gun spraying on spraying distances, gas flow rates, type of powder, etc.; phase composition and properties of coatings is studied. The basic physicochemical transformations that accompany D – gun spraying of coatings of alloy WC – C, such as oxidation and reduction of tungsten carbide in high – temperature oxygen – containing media, interaction of composite coating components are considered problems of modelling of bonding of particles with a part surface during thermal spraying of coatings are considered.
The paper presents a universal principle of design of flexible schemes of specialized technological equipment and a modular principle of design of construction and elements of special technological equipment. The construction elements of equipment, which allow changing the linear dimensions of this equipment in a wide range are designed. The application of designed elements for changing one or several linear dimensions of the equipment is possible in a complex and independently of each other. The possibility of application of proposed design changes of equipment with the preservation of the required strength characteristics is substantiated. Three-dimensional models of construction elements and equipment in general are developed. Researches by changing of reservoir design by using a replaceable construction element are carried out. An analysis of the strength characteristics of integral reservoir and reservoir with a replaceable end wall from various materials is presented.
The problems of modelling of bonding of particles with a part surface during thermal spraying of coatings are considered. The formation of adhesive and cohesive strength of thermal coatings is considered from the standpoint of the theory of welding of materials in solid phase. The formation of interatomic connections between particle materials and parts is accompanied by deformation processes in contact zone, which facilitate the unloading and rupture of connections in the metal – oxygen system, loading and connections between atoms of interacting materials. The kinetics of formation of interatomic connections between materials of particle and substrate at high collision velocities is satisfactorily described by a modified semi – empirical equation that uses experimentally measured quantities: the magnitude of tensile deformation of interatomic connection, the Young’s modulus, the coefficient of thermal linear expansion. Possible influence of nanotopography of substrate surface on the interaction with sprayed particles and formation of coatings with high adhesive and cohesive strength is shown.
Показана роль контактної взаємодії частинок, що напилюються, з основою у формуванні міцних газотермічних покриттів. В якості основних структуроутворюючих елементів в покриттях прийняті сплети – поодинокі напилені частинки. Проаналізовано основні фактори, що визначають структуру і властивості газотермічних покриттів в процесі напилення, причому найважливішу роль відіграє утворення контакту частинка – основа і процеси, що протікають на ньому. Проаналізовано основні фактори, що визначають взаємодію матеріалів частинки та основи. Розглянуто основні роботи, присвячені проблемі схоплювання частинок з основою при напиленні. Запропоновано при аналізі утворення фізичного контакту розглядати площу контакту, що утворюється, з урахуванням розмірів напилюваних частинок і наявності на поверхні основи мікро- і наношорсткості чотирьох рівнів: номінальної, контурної, фактичної і фізичної. Фізична площа контакту на кілька порядків менше контурної площі та на її площадках формуються найбільш міцні адгезійні зв'язки. Запропоновано рівняння для оцінки фізичної площі контакту в зоні дії напірного тиску.
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