The article considers and analyses the methods by which it is possible to carry out research to determine the fire resistance of elements of steel frames of industrial buildings. It is determined that it is expedient to use the means of computational fluid dynamics, which has no limitations due to the high cost, complexity, environmental friendliness and complexity in comparison with real experiments. In order to conduct the most reliable computational experiments, mathematical models of temperature and mechanical reaction to the thermal effect of fire were created, taking into account the equations of thermal conductivity, systems of differential equations of stress-strain state of solids in their numerical implementation based on the finite element method. The solution of mathematical models was carried out using computational fluid dynamics, which describes the process of heat and mass transfer in test fire furnaces during the determination of fire resistance of steel structures. According to the results of computational experiments it is shown that the limiting state of loss of bearing capacity of vertical and horizontal structures occurs due to the formation of a zone of plastic deformations taking into account the associative theory of plasticity. According to the results of computational experiments, the dependence of the limit of fire resistance on the level of applied load to structures, which is close to linear, was revealed. Based on the obtained dependences and the corresponding graphs, a technique is developed based on the use of maximum deformations of the elements with the corresponding fixation of the limit state on the loss of fire resistance in terms of bearing capacity by bending this curve.
Today there is not enough scientific data on the energy level and the velocity of an explosion in actual mine workings, which have a cross-sectional area larger than experimental mine workings. The objective of the paper is to justify the energy parameters of an explosion in actual mine workings based on the disclosure of the fire front development mechanism when coal dust explodes in an experimental mine working with a limited cross-sectional area. These studies can be the basis for choosing the speed of action and the strength of the means of the localization of dust explosions. The main research method is an experimental and analytical method, based on the analysis of the results of experimental explosions of coal dust in experimental mine workings and theoretical substantiation of the regularities of the development of the velocity and additional energy of the fire front with further extrapolation to the conditions of actual mine workings. It is proposed to supplement the mechanism of explosion development with an idea about the sections of development of explosion dynamics, i.e. initiation, dust explosion, crater, which determine the characteristic parameters of the explosive front velocity: maximum initiating velocity, average velocity, and maximum velocity in a crater. It was established that during methane initiation in the experimental mine working at the boundary between the initiation and dusting zones, there is a situation of a hybrid explosion of a mixture of methane and dust with air, which has its own velocity and energy indicators. A linear dependence of the energy generated during the coal aerosol explosion on the cross-sectional plane of the mine working was established. This makes it possible to use the results of testing the coal from certain deposits in small-scale experimental set-ups to justify the parameters of protective means for the actual mine workings.
Development of a functional model of the process of creating a knowledge base on the recognition of objects and actions of the enemy on the basis of neural networks and fuzzy logic. The aim of the work is to develop a set of software and hardware designed for remote identification of hazardous substances by machine visual recognition of information signs of dangerous goods with the output of relevant information to the means of visual display (interface). Recommendations concerning providing UAVs with the necessary technical means to monitor the zone of emergencies are analyzed. The recommendations of the organization of radio communication between the UAV and the operator depending on the range of the UAV departure, terrain conditions etc are analyzed and given. The structural scheme of the complex of remote recognition of HC in the form of blocks, units and software and hardware is developed. As a result of the analysis of programming systems, it was found that Python programming language is the best choice to ensure the full operation of the software due to the built-in capabilities and the involvement of third-party frameworks. A database containing information on more than 3.000 HCs with detailed recommendations for emergency response is developed. The hardware and software complex for remote identification of dangerous substances by machine visual recognition of information signs of dangerous goods by UAV, consisting of unmanned aerial platform with photo-video recording means, data transmission system to ground control station, PC for processing results and related software are substantiated and developed. A test of the UAV's capabilities in recognizing danger signs with UN numbers in different lighting conditions was tested. In all cases, the HC was accurately identified. The ideas and methods proposed in this article will allow to create cheap and simple tools for rescue units of Ukraine, which deal with the consequences of emergencies related to the leakage of HCs.
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