Verification Of Calculations Research Articles

Моделирование процесса обследования железобетонных опор технологических эстакад

The paper presents the process of assessing the technical condition of reinforced concrete supports of existing technological overpasses. The characteristics of overpasses are given. Defects identified in the process of assessing the technical condition are shown. The paper describes the control of concrete strength by the non-destructive method of elastic rebound using the Digi Shmidt 2000 device and the determination of the concrete cover thickness and the location of reinforcement by the magnetic method using the Profometer-5S device. The layout of the working reinforcement in the reinforced concrete supports of the overpass section has been determined. The results of verification calculations of the structures of technological ramps are given, taking into account the revealed defects and damages, the strength of materials and the specified actual loads. Proposals are given for improving the performance of concrete of reinforced concrete supports of overpasses.

Оцінка напружено-деформаційного стану шпинделя багатоопераційного верстата

Запропоновано комплексну процедура аналізу конструкції шпиндельного вузла модернізованого токарного верстата. Наведено конструктивна і розрахункова схеми двухопорного полого шпинделя з використанням модуля аналізу напружено-деформованого стану балок АРМ Bеam. Розглянуто поперечна згортка приводу головного руху токарного верстата і визначена просторова схема сил, що діють на шпиндель. Виконано розрахунок статичної міцності за величиною еквівалентних напружень, що виникають в конструкції шпинделя. Дана оцінка рівня дотичних напружень у поперечному перетині конструкції методом кінцевих елементів.

Comprehensive Survey of the Silt Reservoir Structures Technical Condition

The aim of this work is to obtain information about the condition of the sludge tank supporting and enclosing building structures, identifying and fixing existing defects in order to assess their possible impact on structures during its further operation. Archival surveys were carried out, site documentation was selected and studied, load-bearing structures engineering measurements were carried out, building structures were inspected, and the structural condition was photographed selectively, graphic materials were made, technical conclusions were drawn up with conclusions and recommendations for further structures safe operation in order to achieve this goal. The technical surveying included a building structures external examination with damages fixation. The structures general technical condition of the, the presence and nature of the defect’s propagation were previously visually recorded, and then refined using measuring equipment. Verification calculations were also carried out with the design and current load analysis on the sludge tank elements, and the tank supporting structures concrete strength was determined by the ultrasonic method.

Analysis and Optimization of Three-Beam Traverse Structure Elements for Reactor Cavity Reinforced Concrete Block Installation

Increased demands are placed on the reliability and strength of structures used in the installation of equipment for nuclear power plants. At the same time, an excessive safety margin of the equipment used leads to an increase in its dimensions, weight and a significant rise in cost. The issue of reducing the metal consumption of structures while maintaining the required performance criteria for this equipment is very relevant. The paper presents a model for optimizing the design of a three-beam traverse with a carrying capacity of 100 tons for reactor cavity reinforced concrete block installation. A verification calculation is carried out and recommendations on the optimization of design parameters are proposed on its basis.

Application of Calculation Softs to Perform Verification Calculations during the Survey of Monolithic Reinforced Concrete Buildings

When performing verification calculations during the survey of building structures, the use of calculation software is limited by the standard algorithm, which does not always allow taking into account the impact of certain pathologies and damages on the bearing capacity and stability of structural elements and objects as a whole. The article offers a variant of using the software package “Lira 9.6” to assess the load-bearing capacity of a building with a monolithic reinforced concrete frame, taking into account the most characteristic pathologies for objects of this type.

Positioning automation when assembling panel structures

The article discusses the process of assembling low-stiffness panel structures typical of the aerospace industry. Due to the low stiffness of the incoming elements, the assembly of such structures differs from the assembly of structures typical of general mechanical engineering. To switch to a robotic assembly of such structures, it is necessary to comply with special requirements both to the technology and to the design of the elements included in the assembly. The paper investigates the process of positioning automation during the assembly of panel structures using industrial robots. The article describes a method of verification calculation for accuracy, which allows establishing whether the proposed positioning method meets the specified requirements for the aerodynamic contour of the product. Requirements for structural elements have been formulated, which will allow positioning during assembly with the required accuracy. The results obtained in the course of the study can be used in the design of new structures, the assembly of which will be carried out using automation tools. In addition, the developed requirements must be taken into account when switching to new assembly technologies for existing structures. The results of the study can help to improve the efficiency of assembly of flexible structures used in the aerospace industry. It was also found that it is necessary to conduct further research in terms of the influence of deflections of the structure from its own weight and during the supply of the tool that performs the setting of joints.

Imbalance in the hydrotechnical structure of seaspan lift-transition bridge in sea ferry crossing

The article is devoted to the problem of reliability of functioning of onshore structures of transport systems using the example of railway ferry crossing. A brief assessment of the role ferry crossings at the current stage of the development railway and sea transport was given. The approach to the verification calculation of lifting mechanisms, suspension elements and counterweight devices of the sea span lift-transition road-railway bridge of stage I of the Vanino-Kholmsk ferry complex in the sea port of Kholmsk for the possibility of their use due to an increase in the weight of the span structure after repair was proposed and justified.

A formal proof of the irrationality of ζ(3)

This paper presents a complete formal verification of a proof that the evaluation of the Riemann zeta function at 3 is irrational, using the Coq proof assistant. This result was first presented by Ap\'ery in 1978, and the proof we have formalized essentially follows the path of his original presentation. The crux of this proof is to establish that some sequences satisfy a common recurrence. We formally prove this result by an a posteriori verification of calculations performed by computer algebra algorithms in a Maple session. The rest of the proof combines arithmetical ingredients and asymptotic analysis, which we conduct by extending the Mathematical Components libraries.

Modified efficiency-NTU method (m-ε-NTU) for calculating air coolers in dehumidifying or frost conditions. Part II

This study presents a calculation method that can be applied to counterflow and straight-through air coolers operating in dry (without condensation), wet (with condensation on the entire surface), or nonbinary (with condensation on a part of the surface) modes for cases with and without the cooling medium undergoing a phase transition. Comparing the results obtained from the proposed method with those obtained from the method of segmental division of the heat exchange apparatus showed good convergence, with the proposed method requiring considerable lesser time for their execution. Hence, the novel proposed method can be widely used for the selection, verification, and structural calculations related to air coolers.
 In the second part of this study, the main mathematical relations used for stationary calculations related to air coolers are provided. These dependencies are applicable to the dry, wet, and combined conditions. The method used for performing calculations related to air coolers operating in dry conditions is described herein. Formulas for determining the heat exchange surface with respect to the cooling fluid and humid air are derived herein. Moreover, these formulas can be used for calculations related to air coolers with or without a phase transition of the cooling fluid. Moreover, the criterion of transition of the air cooler from the dry operating mode to the wet or combined mode is provided in this study.

GENERAL METHOD FOR CALCULATING BUTT AND ANGLE WELDS FOR STRENGTH

The existing methods for calculating butt and fillet welds are private, developed for specific design solutions that do not take into account the variety of weld shapes and the variety of combinations of forces and moments. The article provides a general method for calculating butt and fillet welds for strength, based on the calculation method for nominal stresses, adopted in the strength of materials. This technique was used without any changes for the calculation of butt welds, since the weld is an extension of the part. The calculation of fillet welds is based on two assumptions, on the basis of which a calculation scheme has been developed, which makes it possible to use the calculation method for rated stresses. The article proposes two design schemes, considers the calculation procedure and derives two generalized strength conditions for the verification calculation of butt and fillet welds.

An anti-crystallization design of selective catalytic reduction nozzle holder

From the aspect of reducing the risk of crystallization on nozzle surface, a new design of nozzle protective cover was to solve the problem in selective catalytic reduction (SCR) urea injection system. The simulation calculation and experimental verification methods were used to compare different schemes. The results show that reducing the height of nozzle holder can reduce the vortex currents near nozzle surface and effectively reduce the risk of crystallization on the nozzle surface. It is proposed to install a protective cover in the nozzle holder under the scheme of reducing the height of nozzle holder, which can further eliminate the vortex. Simulation and test results demonstrate good agreement under the rated running condition. The scheme of adding a protective cover in the nozzle holder shows the least crystallization risk by computational fluid dynamics (CFD) method. The crystallization cycle test shows that, after the height of nozzle holder is reduced, the risk of crystallization on the nozzle surface is reduced correspondingly. The addition of a protective cover in the nozzle holder solves the problem of crystallization on the nozzle surface, which provides a new method for anti-crystallization design.

Temperature Profile in Rubber Injection Molding: Application of a Recently Developed Testing Method to Improve the Process Simulation and Calculation of Curing Kinetics.

Injection molding of rubber compounds is an easily conducted yet sophisticated method for rubber processing. Simulation software is used to examine the optimal process conditions, identify failure scenarios, and save resources. Due to the complexity of the entire process, various aspects have to be considered in the numerical approach. This contribution focused on a comparison of process simulations with various definitions of the material’s inlet temperature, ranging from a stepwise increase, but constant temperature, to an exact axial mass temperature profile prior to injection. The latter was obtained with a specially designed, unique test stand consisting of a plasticizing cylinder equipped with pressure sensors, a throttle valve for pressure adjustments, and a measurement bar with thermocouples for the determination of the actual state of the mass temperature. For the verification of the theoretical calculations, practical experiments were conducted on a rubber injection molding machine equipped with the mold used in the simulation. The moldings, obtained at different vulcanization time, were characterized mechanically and the results were normalized to a relative degree of cure in order to enable comparison of the real process and the simulation. Considering the actual state of the mass temperature, the simulation showed an excellent correlation of the measured and calculated mass temperatures in the cold runner. Additionally, the relative degree of cure was closer to reality when the mass temperature profile after dosing was applied in the simulation.

The Passivity of Pure Nickel in Alkaline Solution under Different Temperatures: Electrochemical Verification and First-Principles Calculation

Properties of a passive film formed on pure nickel in an anaerobic alkaline solution are investigated by a first-principles calculation and electrochemical experiments in this work, and both results show agreement with each other. The formation energy of nickel vacancies is lower than that of oxygen vacancies in the NiO film, which is consistent with the deduction of the point defect model in which nickel vacancies impart p-type semiconducting character to the passive film, as confirmed by Mott–Schottky analysis. The density of nickel vacancies (approximately 1021 cm−3) in the passive film increases with temperature but decreases with the film-formation potential. The thickness of the passive film increases linearly with the film-formation potential, as verified both by Auger electron spectroscopy and electrochemical impedance spectroscopy. The diffusion coefficient of the nickel vacancies increases from 10−18 to 10−16 cm2/s as the temperature rises from 298 to 348 K, respectively, in experiments using high-field equations and first-principles calculation.

Doses to Organs at Risk Calculated Using Plato and Oncentra Softwares in Intracavitary Brachytherapy

This is a retrospective study, the organ doses to the bladder and rectum were compared between Nucletron PLATO V14.2.3 (BV) and newer version software Oncentra MasterPlan V4.3 (OMP) treatment planning systems (TPS). The treatment data of 32 intracavitary brachytherapy patients at Hospital Universiti Sains Malaysia from January 2010 to June 2015 were used. These data sets were used for catheter reconstruction for both PLATO and OMP TPS followed by independent verification using Excel. There is no significant difference in mean doses to organs at risk (OARs) that calculated by both TPS (p>0.05). The mean percentage of doses calculated by PLATO TPS for bladder and rectum were 66.58 ± 27.42 % and 46.27 ± 14.47 % respectively. While the mean percentage of doses for bladder and rectum calculated by OMP TPS were 65.68 ± 24.24 % and 46.46 ± 16.66 respectively. The mean percentage difference in doses comparison between independent verification calculation and PLATO TPS was 1.96 ± 6.00% and then became 6.37 ± 5.17% when it was compared with OMP TPS. Overall, the dose calculation differences for both versions of TPS were within the range recommended by Nuclear Regulatory Commission (NRC). The dose calculations of the two treatment planning systems showed good agreement and both could be used in planning intracavitary brachytherapy for cervical cancer. Whereas Excel based independent verification suitable to be implemented as routine dose verification programme prior to treatment delivery.

APPROACH TO VERIFICATION OF THE TARGET AUDIENCE MODEL OF PSYCHOLOGICAL INFLUENCE IN SOCIAL NETWORKS

Modern planning of psychological operations is not possible without the use of information technology, such as modeling tools that ensure the accuracy of planned operations and predict their results. Modern technologies also help to facilitate the perception of information through visualization. Any information, especially on social networks, is easier for analysts to process if it is presented in a schematic form. For example, the target audience of psychological influence in social networks can be represented by a graph. The article solves the urgent problem of verifying the model of the target audience of psychological influence in social networks. The approach to model verification is based on a combination of cognitive criteria of topological structure. Classical methods of verification of mathematical models are used for verification of mathematical calculations. Data visualization is taken as the basis of the cognition criterion. The article presents a method of graph visualization, which sets the mathematical model of the target audience. Visual representation of the graph not only promotes better assimilation, but also speeds up the analysis of the collected information about the target audience through automation. The data obtained during the run of the model are compared with real data, thus confirming the conformity of the behavior of the model to real phenomena. Validation of the model with the help of software was performed by tracing the model. The adequacy of the model is based on the possibility of analysis of the target audience by the user according to the characteristics of individual actors, which make it possible to determine their role and analyze the structure of the target audience as a whole. The theory of analysis of social networks is the basis of the choice of characteristics of the target audience. To assess the adequacy of the model, two characteristics of the target audience were chosen, as centrality in mediation and centrality in its own vector. The results of the calculations are presented using the software application Gephi. Data from the VKontakte social network were used as input data to check the adequacy of the model.

Применение комплексного подхода к определению надежности и остаточного ресурса дымовых труб промышленных предприятий

The article discusses the problem of determining the reliability and residual life of chimneys of industrial buildings, taking into account an integrated approach, which includes calculating the reliability of the "Chimney" system using the theory of graphs.
 Four chimneys were considered as objects for assessment: three brick and one metal. During the inspection, typical damage to each type of structure was revealed, the results of measurements of the strength of materials and verification calculations were analyzed.
 It was found that the results of calculating the residual resource of brick pipe No. 1 (the residual resource is exhausted, the structure is inoperative) is confirmed by the result of calculating the roll of the building (the roll exceeds the maximum allowable). Also, as a result of the calculation using a comprehensive methodology, the reduced reliability of metal pipes was confirmed in comparison with brick chimneys.

Thermal-hydraulic performance evaluation of annular fuel based on modified FROBA-ANNULAR

In this study, based on the modification of the pellet cladding mechanical interaction, gap closure process, and the cladding water corrosion model, Fuel Rod Behavior Analysis-ANNULAR (FROBA-ANNULAR) was uprated. The modified code was verified with FRAPCON-ANNULAR and ABAQUS. The verification calculation was under low power density when both two gaps were open. The calculation results showed good agreement. The modified code was then utilized to evaluate the annular fuel behavior, compared with the original code FROBA-ANNULAR. In this study, the annular fuel exhibits a much lower peak fuel temperature(about 900K). The different results for heat flux fraction(0.55 for the original code, 0.66 for the modified code) indicated that the gap closure process strongly affected the movement of the adiabatic pellet line. The internal pressure results (7.5 MPa for the original code, 6 MPa for the modified code) were also affected by the different assumptions. The results also showed that Zr's oxidation thickness and hydrogen concentration were related to both time and temperature. The higher the temperature was, the larger the oxidation rate was when the transition thickness was reached.

Parametric Optimization of Load Bearing Elements for Composite Wing of an Unmanned Aerial Vehicle

This paper describes the optimizing results of structural elements of the composite wing of an unmanned aerial vehicle. The thickness and composite lay-up structure of load-bearing elements and wing skin are determined using the ANSYS software package. The optimal structure is presented using the Pareto set method of the “ideal center” basing on four criteria: minimum mass, deflection, normal stress, and maximum safety factor of the wing. Verification calculations were carried out to determine the safety factor of the load-bearing wing structure using a geometrically nonlinear model in FEMAP software.

Научные основы проектирования оптимальных конструкций тихоходных синхронных генераторов с постоянными магнитами для ветроэнергетических установок

In this paper, the scientific basis for designing wind power plants (WPP) with low-speed synchronous generators on permanent magnets (SGPM) is understood as a system of scientific knowledge that forms the theoretical basis for the practice of designing a complex object, such as WPP consisting of interconnected equipment and structures designed to convert wind energy into electrical energy. Currently, the development of advanced WPP designs is receiving increased attention around the world. For example, in the Russian Federation, a promising direction is the creation of Autonomous WPP with low-speed medium- and low- power SGPMs that have the maximum range of applications by type of activity and climate zones throughout the territory. However, engineering approaches to the design of individual components of the WPP indicate the difficulties of developing a scientifically based methodology for optimizing the parameters of the WPP as a whole taking into account the mutual influence of individual components on each other. At the same time, the methodology for optimizing the parameters of WPP is understood as a tool for the scientific basis of design, which takes into account quality indicators and optimality criteria, energy and technical characteristics, as well as design stages with the results of preliminary and verification calculations. For the stage of verification calculations of VEU parameters, the scientific basis of design is determined by the construction of mathematical models and their research using application software packages for PCs, while for the stage of preliminary calculations, the development of analytical methods of analysis is important. This article discusses the scientific basis for designing wind turbines at the stage of preliminary calculations, formulated the problem of optimizing the parameters of low-speed WPP, proposed equations for the relationship of design parameters with the energy performance of wind turbines, providing the maximum efficiency of synchronous generators, taking into account the specified technical conditions

Optimization of structure parameters in a coal pyrolysis filtration system based on CFD and quadratic regression orthogonal combination and a genetic algorithm

An optimization method of structure parameters based on the quadratic regression orthogonal combination (QROC) and Genetic Algorithm (GA) is proposed in this work. The following work has been conducted to improve the performance of the coal pyrolysis filtration system and prolong the service life of the filter tubes based on QROC-GA method. Firstly, a simulation model is established and two factors always are chosen as optimization objectives. Then one single factor regression prediction algorithm is used to optimize each factor separately while the result was not satisfactory. Secondly, QROC is introduced to achieve the optimization of two factors in the filtration system. The regression relationship is obtained proved to be effective by statistical test and back propagation neural network (BPNN). Finally, a QROC-GA method is established to find the optimization points. Then a verification calculation is done with CFD again. The optimal result has the parameters that φ=40° and ψ=25°. From the simulation results, the mean square error is 0.401. The mean square error is 0.4992 by the QROC-GA results. The errors are within 0.1 between CFD and QROC-GA. The QROC-GA model has a good effect in the prediction of models under changing parameters, and the significance is also confirmed.