METHOD OF THEORY OF DIMENSIONS IN EXPERIMENTAL RESEARCH OF SYSTEMS AND PROCESSES

The method and parameters of experimental modelling of systems and processes in mechanical engineering are substantiated. The theory of similarity and dimensionality is used as an intermediate link between theory and experiment. The dimension of the factor space depends on the number of factors. The set of factors is grouped into dimensionless similarity criteria. The selected criteria are in certain dependence, such as the Galileo test, Euler and Reynolds numbers. Examples of application in experimental studies are given. The use of dimension theory in a factor-planned experiment allows reducing the number of factors, simplifies the mathematical interpretation of the response criterion and provides a graphical representation in the form of 3-D model.

Energy analysis of transfer processes and their main characteristics in thermo mechanical damping systems

The article discusses the energy analysis of transfer processes in the damping system. The basic theoretical foundations based on the equations of the energy balance of the hydraulic shock absorber and the law of conservation of energy are presented. The proposed approach is associated with the development of a methodology and scheme for calculating the technical system of vibration damping. The schemes of interaction of the system through the phenomena of transfer and functioning of the vibration protection system with the environment are presented. It is shown that damper systems are based on the physical process of transformation of mechanical energy into thermal energy with subsequent dissipation into the environment. The total energy distribution in damping problems takes the following form the mechanical energy of motion is absorbed due to the hydraulic resistance of the liquid and turns into a dissipative component, which can reach 80% of the total energy. A mathematical model of the law of conservation of energy is presented which includes a dissipative function. The analysis of how it is possible to design work processes in a shock absorber due to energy dissipation and similarity criteria: Euler, Froude, Reynolds, etc. As a result of physical experiments, it was found that the movement of a fluid in hydraulic calibrated throttles gives rise to cavitation and various physical phenomena and accompanying processes, in which there is a significant change in the energy balance and energy dissipation in non-stationary modes of fluid movement. The dependence of the total power loss of the shock absorber under changing operating conditions, and the diagram of physical processes and energy transformations in the problems of damping, which are in dissipative processes, are given. The article describes the principles that can be used for the design of devices and modules of damper systems of a wide class with the possibility of energy recovery and accumulation by introducing a damper into the system, for example, a motor generator, an inductor with permanent magnets or a peso element in the design of a traditional telescopic shock absorber.

Roof Subsidence and Movement Law of Composite Strata Mining: Insights from Physical and Numerical Modeling

Sinking and horizontal movements are necessary parameters for assessing the potential impacts of surface subsidence in mining activities. Based on similarity criteria, the surface subsidence mechanism was studied using a physical model composed of similar materials such as sand, cement, and gypsum. With constant field geological parameters maintained in two angles of a coal seam, models of roof subsidence of composite rock were compared for different mining configurations. In accordance with observations from the physical model, it was concluded that subsidence and horizontal movement of strata near to and far from the coal seams were different and divided into five zones. The zone above a mined-out area underwent greater total subsidence compared to unexploited regions on both sides. Correlations between a subsidence curve and the height of a caving zone and the mining dip angle were obtained and verified from numerical model results. According to the roof’s position relative to the goaf, the area above the goaf of the composite rock layer was divided into three regions: a curving zone, a water-conducting fracture zone, and a falling zone, to which the subsidence and movement characteristics of each area could be proposed. Compared with the subsidence and movement characteristics observed from the physical and numerical model, the acquisition of subsidence characteristics and parameters in different areas can provide an idea for improvement, innovation or proposal of a theoretical formula for subsidence prediction of composite rock formations.

Research of model tests of parameters move-ment of the goat crane under action of load loads

The results of experimental researches of parameters of movement of the model of the gantry crane under the influence of wind loadings are resulted. The assessment of the accuracy and reliability of the obtained results is performed and further directions of research are outlined. The adopted test program included the definition of similarity criteria and scale of the model, where the main parameter was the speed of the crane when exposed to wind. The influence of various factors and assessment of the impact of their interaction was achieved by conducting PFE type 24.

Algorithm for the set of similarity criteria formation for a physical process in the class of homogeneous functions

The efficiency of application of linear programming methods to problems of the theory of similarity and dimensions is shown. A general algorithm for formation of the set of similarity criteria for a physical process in the class of homogeneous functions is proposed. The set of systems of linear algebraic equations is created using the combinatorial method and chain diagrams. Basic and free variables and their corresponding variants of dimensionless sets of independent arguments, which are taken as the main similarity criteria, are distinguished. The set of derived similarity criteria is found using the basic criteria and the Cayley table.

Criteria for multiphysical similarity of the trawl complex

При решении основных задач проектирования и управления тралового комплекса, характеризующие: механические; гидродинамические; грунтодинамические; трибологические; электродинамические; термодинамические; световые; акустические и оптические процессы возникает необходимость обеспечения критериев подобия соответствующих процессов, выполнение автомодельности для сокращения параметров, влияющих на выходные характеристики тралового комплекса. В данной статье рассмотрены критерии мультифизического подобия траловых комплексов (донного и разноглубинного). Критерии мультифизического подобия тралового комплекса определенны с помощью теории мультифизического подобия тралового комплекса. В результате были теоретически обоснованы критерии мультифизического подобия тралового комплекса, на основе которых была разработана программа для ЭВМ «Критерии мультифизического подобия процессов рыболовства». When solving the main problems of design and control of the trawl complex, characterizing: mechanical; hydrodynamic; soil-dynamic; tribological; electrodynamic; thermodynamic; light; acoustic and optical processes, it becomes necessary to provide similarity criteria for the corresponding processes, to perform self-similarity to reduce the parameters that affect the output characteristics of the trawl complex. This article discusses the criteria for the multiphysical similarity of trawl complexes (bottom and midwater). The criteria for the multiphysical similarity of the trawl complex are determined using the theory of the multiphysical similarity of the trawl complex. As a result, the criteria of the multiphysical similarity of the trawl complex were theoretically substantiated, on the basis of which the computer program «Criteria for the multiphysical similarity of fishing processes» was developed.

TIPOLOGI GEOMETRI BANGUNAN MEUNASAH DI KECAMATAN INDRAJAYA KABUPATEN PIDIE, ACEH

The function of the meunasah in the social system of the Acehnese people is a place of worship, a center for religious and cultural education and is also a place to discuss social problems that occur in community life in the village. The search for characters is important to find typology of meuansah, so that the relationship between geometric typology and shape has a broad interpretation. The search for shape characters to find typology of meunasah in Indrajaya District, Pidie Regency, Aceh was carried out in 5 stages, (1) determine the location of the meunasah building sample points in 52 villages in Indrajaya District, (2) literature review, (3) collecting data on the object of research by measuring the meunasah building, (4) redrawing the meunasah measurements that have been carried out at the data collection stage using digital applications to produce data, namely the meunasah floor plans and facades in each village and the last stage is (5) analysis of determining the type with a geometric approach with architectural elements of the meunasah building facades, namely doors, columns, windows, walls, roofs, floors and terrace fences. The findings consist of 16 types of meunasah typology with similarity criteria of typology variable forms.Abstrak: Keberadaan bangunan meunasah dalam sistem sosial masyarakat Aceh berfungsi sebagai tempat ibadah, pusat Pendidikan kegamaan dan kebudayaan dan juga merupakan tempat untuk mendiskusikan berbagai permasalahan sosial yang terjadi dalam kehidupan masyarakat di gampong tersebut. Pencarian terhadap karakter menjadi penting untuk menemukan tipologi dari meunasah, sehingga katerkaitan tipologi geometri dengan bentuk memiliki intepretasi yang luas. Pencarian karakter bentuk untuk mememukan tipologi dari meunasah di Kecamatan Indrajaya Kabupaten Pidie, Aceh dilakukan melalui 5 tahap yaitu (1) menentukan lokasi titik sampel bangunan meunasah di 52 gampong di Kecamatan Indrajaya, (2) penguatan referensi, (3) pengumpulan data objek penelitian dengan cara pengukuran bangunan meunasah, (4) menggambar ulang pengukuran meunasah yang telah dilakukan pada tahap pengumpulan data menggunakan aplikasi digital untuk menghasilkan data yaitu gambar denah dan tampak meunasah di setiap gampong dan tahap yang terakhir adalah (5) analisis menentukan tipe dengan pendekatan geometri dengan variabel elemen arsitektural dari fasad bangunan meunasah antara lain pintu, kolom, jendela, dinding, atap, lantai dan pagar teras. Penemuan berupa 16 tipe dari tipologi meunasah dengan kriteria kesamaan dan kemiripan dari bentuk variabel tipologi.

Experimental studies of the kinematics flow and bottom’s reformations in the area of bridge pier during the construction of the bridge crossing

The results of laboratory modeling of bottom reformations in the area of bridge pier crossing over water barriers are presented. The basics of hydraulic modeling are described taking into account the similarity criteria. The flow around a rectangular box (tongued-and-grooved protection of a constructed pier) is experimentally studied, the pattern of erosion if an ice-cutter device is installed in front of the box in the form of a triangle directed at an acute angle towards the flow is considered. The structure of the bottom relief in the vicinity of the tongued-and-grooved box is experimentally studied under the conditions of the bottom erosion. Two cycles of experiments were performed for different values of the flow depth and specific discharge of water. Localization and quantitative characteristics of washouts and alleviation of sandy soil in the vicinity of the streamlined design are established. It is noted that the main mechanism for the formation of the bottom relief is a horseshoe vortex at the base of the pier. A stagnation zone is formed inside the horseshoe. In the absence of an ice cutter, the main zones of soil erosion occur in the corners of the frontal bezel of the box, alluvium forms in the rear unit of the design. By installing an ice-cutter device in front of the box, the erosion zones move to the vicinity of the corners lying at the base of the triangular ice-cutter facing the box. The alluvium remains in the wake of the box. At the same time, the absolute values of the erosion depth and the height of the alluvium under installing the ice-cutter close to the box are reduced. The data of velocity measurements on the free surface and in the flow thickness are also given.

Nanotechnologies in agricultural production as a factor of transition to a new level of technological design

The article discusses one of the directions of the transition of agricultural production in Russia to the sixth technological order based on the introduction of nanotechnology in the field of hygrothermal effects on grain crops. The features of hygrothermal action on grain under vacuum conditions are presented. The distinctive features of such processing as nanotechnology are substantiated. Based on the method of similarity in the functioning of technical systems for vacuum-capillary processes of humidification, drying, and wet-heat treatment, generalized similarity criteria are obtained, their numerical values are determined, and generalized criterion dependences of the intensity of the processes under consideration on the processing parameters are obtained. The implementation of this method made it possible to quantitatively describe the processes of vacuum capillary hygrothermal treatment of grain, to assign processing parameters and control them.

Design the technological process and equipment using fields and energy flows based on analysis of similarity criteria

It is shown that the use of transfer criteria for analysis of the formation processes of structures and phases significantly reduces the amount of experimental research in the design of technological process and equipment using fields and energy flows. It is proposed to use the ratios proportional to the criteria of heat and mass transfer, physicochemical interaction when controlling energy sources. It is shown that the modeling of the combined electromagnetic and thermomechanical effects in the design of technological process and equipment is based on the criteria of heat and mass transfer, electrical and physicochemical interaction, determines the main technological factors, and relates geometric and physical parameters, as well as mechanical quality parameters with the processing performance.