Simulation Modeling Method Research Articles

Features of development of a digital twin of the transport system of an urban area using simulation modeling methods

The relevance of the study is justified by the growing share of urban population and their active use of personal automobile and public transportation. All this increases the mobility of the population and requires the development of transportation infrastructure in the established urban development. Solving such problems requires the development of models that simulate all aspects of the real object of the transportation system. With their help it is possible to conduct experiments on changing individual characteristics of the system in order to assess its response to control actions. The object of the study is Pervomayskaya Street at its intersection with the Tretya Parkovaya Street in the Izmailovo district of the Eastern Administrative District of Moscow. The article presents the stages of simulation model creation and their corresponding results in the form of models characterizing traffic flows, system objects and their behavior.

Simulation modeling as a means of forecasting passenger traffic at the Moscow Central Ring station

The article presents the results of creating a digital twin of the Moscow Central Ring station “Izmailovo” using simulation modeling methods. The study’s main goal is to create a formal model demonstrating, at given time intervals, the changes in the objects and processes that make up the model when certain input parameters are changed. The results obtained during the simulation of the system behavior allow for evaluating the effectiveness of the concepts for the modernization of the transport system facility in terms of passenger traffic. The conducted structural analysis of the research object allowed to establish all elements and their corresponding characteristics to create models of the behavior of key objects. Additionally, a 3D graphical model has been developed to demonstrate the behavior of all objects and their corresponding processes.

Electric charging stations for electric vehicles in a traffic flow simulation model

This article substantiates the need to use simulation modeling in planning the location of parking lots equipped with charging stations for electric cars. Moscow is actively developing infrastructure for the use of electric cars for personal use, but there is a limited number of charging stations in the city districts. This increases the load on the transportation framework of the capital. Creating a simulation model of the transport system allows us to identify its “bottlenecks” related to the effective organization of road traffic and the creation of a sustainable environment. The use of methods of structural analysis, synthesis, groupings, information and simulation modeling allowed to establish all key objects of the problem area, their qualitative and quantitative characteristics necessary to create a simulation model. The created simulation model is based on the developed formal models of changes in the states of each class of objects, corresponding to the behavior in the real urban environment. To demonstrate the obtained results, a three-dimensional model corresponding to the simulation model is developed.

Vibrational thermal pool multi-level theoretical model and design simulation of HBr-filled hollow-core fiber gas laser

The hollow-core fiber gas laser (HCFGL) has developed into a significant mid-infrared laser source, but the development of theoretical model still lags behind experimental progress. In this work, we propose a multi-level vibrational thermal pool (VTP) model of HBr-filled HCFs, which comprehensively considers the rovibrational relaxation effects on laser gain in reasonable approximations of transition coefficients, and studies the laser characteristics on multi-line lasing, bottleneck effect, line competition, etc. The VTP model shows more precise results of laser slope efficiency, and threshold than previous models while fitting the experimental data very well, and successfully predicts an output bottleneck at 1 W pump. The P-branch laser is relatively advantageous over the R-branch laser for its larger Einstein <inline-formula><tex-math id="M1">\begin{document}$A$\end{document}</tex-math><alternatives><graphic specific-use="online" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="15-20240428_M1.jpg"/><graphic specific-use="print" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="15-20240428_M1.png"/></alternatives></inline-formula> coefficient and emission cross section, and the seed injection can intensify the line competition and reach the highest P4 power proportion of 80%. The VTP model reveals that the output of various pump lines has a pattern similar to the Boltzmann distribution, suggesting that the distribution of ground rotational levels limits the laser gain of pump lines. Moreover, we discuss the photon leakage in high-energy pulsed pumping conditions. With the introduction of the leaking coefficient, this model shows relaxation oscillations and laser slope efficiencies close to experimental values and greater than the results in the CW condition, and solves the overpump problem in pulsed pump simulation. Finally, we confirm that the photon leakage is intensified at high repetition rate and the leaking coefficient should relate to the pulse repetition rate. This work develops a comprehensive modeling method for MIR laser simulation and this model is also applicable to various gas-filled HCFGLs.

Features of development of an agricultural warehouse digital twin

The article presents the main results of the development of simulation model of agricultural warehouse. Such a model is a digital twin of the real object that reflects all qualitative and quantitative characteristics of objects and included processes. The creation of such digital twin is necessary to assess the effectiveness of the organization of storage, packing, loading and unloading of agricultural products. The relevance of the research lies in the specificity of realization of the above processes due to their intensity depending on the season, microclimatic conditions of the premises, fragility, and short life of products. As a result of using the methods of structural analysis, simulation modeling and graphical method, all key objects and processes of the subject area are established and characterized, behavioral models and three-dimensional visualization of the simulation model are developed.

Bispectral analysis and simulation modeling of quadratic nonlinear system with specific turbulent-fluctuation-excitation-response types

There exists a kind of quadratic nonlinear system with specific type of turbulent fluctuation excitation in nature, which belongs to a special non-Gaussian input signal system. Its characteristic is that the input signal spectrum is generated by turbulent fluctuations, and the power spectrum distribution of this turbulence fluctuation signal is close to Gaussian distribution. Starting with the work of Choi et al. (<ext-link ext-link-type="uri" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://doi.org/10.1016/0022-460X(85)90370-0">1985 <i>J. Sound Vib</i><i>.</i> <b>99</b> 309</ext-link>) and Kim et al. [<ext-link ext-link-type="uri" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://ieeexplore.ieee.org/document/1145286">1987 <i>IEEE J. Ocean. Eng.</i> <b>OE-12</b> 568</ext-link>), we extend the simulation of a specific turbulent fluctuation excited response-type quadratic nonlinear system represented by the wave excited mooring ship response, and fully develop the internal development of turbulence based on bispectral analysis technology. We also extend the simulation system and conduct systematic modeling analysis. The complete iterative method [<ext-link ext-link-type="uri" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://doi.org/10.1088/1402-4896/ab725f">2020 <i>Phys. Scr.</i> <b>95</b> 055202</ext-link>] is used to solve the model, and calculate the linear transfer function and quadratic nonlinear transfer function. The comparison of simulation and modeling results with the real systems and their models confirms the correctness of the results from system simulation, system modeling, and model solving. The results obtained are all in line with expectations. The coherence analysis shows that the quadratic coherence of the random wave-ship swaying system is much greater than the linear coherence, but the linear coherence of the fully developed turbulence is greater for the near Gaussian input type. The reverse computation verification or comparison with real systems indicates that the turbulence simulation and system modeling method in this work have good accuracy and high efficiency in solving algorithms, and the research results can be effectively applied to the model description and system analysis of the quadratic nonlinear systems related to specific turbulent fluctuation excitation response.

Vibrations of a dual-rotor system in aero-engine induced by the support misalignment

In this paper, an analytical model of a rotor-bearing-rotor coupling system is established for aero-engine from the Lagrange equation, based on the dynamics theory of the dual-rotor system and combined with its stiffness, damping, and misalignment characteristics. In the model, the misalignment fault simulation method is introduced. The coupling effect between the low-pressure rotor and high-pressure rotor and the influence of misalignment of the support on low-pressure coupling are considered. The vibration characteristics of the dual-rotor system with the misalignment fault of the low-pressure turbine rear support are studied. The time-domain responses, the frequency spectra, and the shaft-center trajectory of the dual-rotor system with different misalignments are obtained. The influence of unbalance on the vibration characteristics of the low-pressure rotor and the high-pressure rotor with misalignment fault is analyzed. Finally, test verification is carried out by the designed dual-rotor test rig. The experimental results are consistent with the analytical results, confirming the established model's feasibility and simulation method in this paper. The results may provide a theoretical basis for research on the misalignment fault in aero-engine dual-rotor systems.

Simulation modeling as a tool for predicting pedestrian flows when planning a Moscow Metro surface station

The article substantiates the use of simulation modeling methods to organize efficient and safe passenger movement at the metro station. The list of key objects and their corresponding processes at ZIL station, a part of the Moscow Central Ring (surface line of the Moscow Metro), is determined using structural analysis methods. Based on the results obtained, the input parameters of the simulation model and the rules for realizing the processes corresponding to them were determined. Using specialized software tools, a 3D computer model has been developed that complies with the established rules and demonstrates all aspects of the subject area. Fragments of the model realizing certain scenarios of passenger movement through the station facilities are presented. The obtained model can be used to develop the concept of sustainable development of urban areas and transportation.

Simulation modeling in environmental aspect of sustainable development in retail sector

Russian food retailers are actively modernizing their operations in accordance with the principles of sustainable development. Renewable energy technologies are being developed and actively implemented, waste is being reduced and utilized, and social projects are being implemented. To reduce the negative impact on the environment, it is necessary to develop and implement innovative technologies and business process management techniques. The use of simulation modeling methods provides an opportunity to predict changes in the development and implementation of new solutions. In the paper a structural analysis of the processes characteristic for the sales halls is carried out, key objects and their characteristics are determined. On the basis of this analysis, the rules determining the change of states of objects and processes are established. On the basis of the obtained results, the corresponding formal models are created, which are intended for conducting numerical experiments to determine effective management strategies. The created models can be used in the development of expert systems that manage certain resources of the retail network in order to reduce the negative impact on the environment.

Simulation modeling of forest plantation condition

The article substantiates the necessity of creating a simulation model of changes in the states of forest plantations. Such a model makes it possible to repeatedly conduct experiments on the object of study on changes in different parameters in order to predict the consequences and develop operational management scenarios to reduce the negative impact on its processes and objects. The use of structural analysis, synthesis and classification methods allowed us to identify the key objects of such an ecosystem and the processes that influence their germination, growth and death. The results obtained became the basis for the creation of a system dynamics model reflecting the nature of the behavior of the objects and processes under study. With the help of simulation modeling methods, a system of differential equations was created, which takes into account the quantitative instances of objects and the rate of their changes depending on external parameters. Based on this, a graphical model reflecting all aspects of the realization of such processes has been created.

Simulation model for predicting ecological condition of urban areas at traffic intersections

This article substantiates the relevance of the development and use of digital tools that allow modeling objects and processes of transport systems to determine the environmental consequences of changes in their quantities and states. The use of methods of structural analysis, systematization, observation, statistical analysis of data allowed to establish all key objects of the system and their qualitative and quantitative indicators necessary to create a digital twin. The use of simulation modeling methods allowed to formalize the obtained results into models involved in the digital twin of the transport system. Using the graphical method, state diagrams were developed to demonstrate the transition of states of each object of the process depending on changes in environmental conditions. On the basis of the statistical analysis of pollutant emissions in the study area, a parametric model was developed for each pollutant factor.

Digital models for assessing the impact of aeration processes on reservoir aquaculture

The dissolved oxygen level in a water body is one of the problems affecting all its processes and living organisms. The article identifies the problems associated with insufficient oxygen concentration in water and affecting the ecosystem both within a water body and in the surrounding area. A system dynamics model is developed to predict such changes. The key objects and processes established through structural analysis, observation, synthesis, and mathematical statistics are at the heart of such a model. The application of simulation modeling methods to the obtained results allowed the creation of a model reflecting the dependence of parameters affecting the rate of processes and changes in their states, affecting the population of fish and other living organisms in the reservoir.

Study on Smoke Spreading Characteristics of Highway Tunnel Fire

In the event of a fire in a road tunnel, the effect of natural smoke exhaust alone is far inferior to that of mechanical smoke exhaust. Study of the characteristics of the flux of smoke gases inside the tunnel with the use of mechanical exhausts in case of sudden fire in road tunnels by means of specific model simulation methods, specific analysis by setting fixed exhaust spacing and different emission volumes, and the addition of fine water mist is studied. The results show that: when the exhaust vent spacing is 30m, the smoke exhaust volume in 30m³/s, 40m³/s, 50m³/s mechanical smoke exhaust device under the action of temperature, CO concentration and visibility will not affect the safe evacuation of the personnel, but taking into account the control of smoke propagation and economic reasonableness, the smoke exhaust volume of 40m³/s is better than the smoke exhaust volume of 30m³/s and 50m³/s. Under the coupling effect of mechanical smoke exhaust system and fine water mist, the spread of smoke in the tunnel can be controlled within a certain range and the internal temperature of the tunnel can be reduced. It can provide a certain basis for the design of the exhaust vent and the setting of water mist in the future.

Model Simulation and Rheological Research on Crosslinking Behavior of Polyethylene Resin.

The crosslinking behavior of polyethylene (PE) determines its exceptional performance and application. In this study, we investigated the crosslinking behaviors of different PE resins through model simulation and rheological methods. Specifically, the mathematical equation of "S" model was established for PE resin. According to this equation, the optimal maximum gel content for high-density polyethylene (HDPE) was found to be around 85%. Moreover, the maximum crosslinking degrees for different PE resins depended largely on their density and molecular weight. The melt viscosities before crosslinking in PE resins were highly influenced by their melt index. The higher melt indexes resulted in the lower storage moduli, improving melt processability during processing. In addition, the crosslinking rates of PE resins were strongly influenced by peroxide concentration, independent of PE resin structures. For high molecular weight and low-density PE resins, they exhibited decreased ti values, increased A0 values, and decreased k6 values. However, there were no noticeable variations in the values of k2 and phi among different PE resins. All simulated modeling outcomes showed remarkable consistency with the experimental rheological data. These findings are of strong significance in the industrial manufacture of PE resin.

Study of Error Flow for Hydraulic System Simulation Models for Construction Machinery Based on the State-Space Approach

This study presents an error flow research method for simulation models of hydraulic systems in construction machinery based on the state-space approach, aiming to ensure the reliable application of digital twin models. Initially, a comprehensive analysis of errors in the simulation modeling of hydraulic systems in construction machinery was conducted, highlighting simulation model parameters as the primary error sources. Subsequently, a set of metrics for assessing the accuracy of simulation models was developed. Following this, an error flow analysis method for simulation models of hydraulic systems in construction machinery was explored based on the state space approach, delving into the sources, transmission, and accumulation of errors in the simulation modeling of valve-controlled cylinder systems. The research results unequivocally indicate that the spring stiffness, viscous damping coefficient, and hydraulic cylinder external leakage coefficient are critical parameters affecting the accuracy of valve-controlled cylinder system simulation models. Furthermore, it was observed that the simulation model of the control valve has a significantly greater impact on the errors in the valve-controlled cylinder system simulation model than the hydraulic cylinder model. In conclusion, the reliability of the error flow model was confirmed through simulation experiments, revealing a maximum relative error of only 3.73% between the error flow model and the results of the simulation experiments.

Determination of Parameters for Limiting Longitudinal Acceleration to Optimize Energy Consumption for Train Traction

Purpose. The main purpose of the article is to improve traction calculations using mathematical modeling when solving the equation of train motion. The train model is adapted to optimize the parameters of train movement during speed gain with the determination of functional relationships between the power of the locomotive power plant and the profile of the track section with the consumption of energy resources by the locomotive. Methodology. Modern methods of mathematical modeling were used to solve the tasks. The modeling of the power plant operation was performed using interpolation and approximation methods. The simulation modeling method was used to create a model of the electrical part of the diesel locomotive transmission. The method of integrating the differential equation of motion was used to calculate the parameters and nature of the train's movement and the problem was solved, which consists in finding a solution to this equation over the length of the traction section, taking into account the variable values of the locomotive power and the slopes of the track profile. Findings. To analyze the results of traction calculations, we obtained such indicators as technical speed and diesel fuel consumption, and compared these indicators. The results show that in the case of acceleration limitation, there is a decrease in diesel fuel consumption at almost unchanged technical speed. Originality. The improvement of energy efficiency of train operation has been further developed, namely, the functional dependence of the relative power of the locomotive power plant, which takes into account the actual profile of the site, has been obtained, which makes it possible to determine energy-saving modes of locomotive control and reduce energy consumption, load on the diesel engine and elements of the diesel locomotive traction transmission during transient modes, which, in turn, in addition to saving diesel fuel, will affect the reliability of the power plant elements. The practical value of the study is to save diesel fuel in the modes of movement that provide speed gain and increase the reliability of the power plant due to reduced load.

The use of simulation modeling when choosing the option of reconstruction of the St. Petersburg-Main station in connection with the commissioning of HSH-1

Aim: with the use of simulation modeling, analyze and choose the most rational option for the reconstruction of the St. Petersburg-Main station with partial preservation of the Kokorev warehouses included in the list of cultural heritage objects. 
 Methods: methods of simulation modeling. 
 Results: the analysis of three options for the reconstruction of the stations St. Petersburg-Main and St. Petersburg-Tov.-Moscow, necessary in connection with the construction of the St. Petersburg-Moscow high–speed highway (HSH-1) and the arrangement of the final terminal of HSH-1 on the territory of the apron park of the St. Petersburg-Main station. By the method of simulation modeling, the necessary and sufficient track development of the stations was determined, a reconstruction option with partial preservation of the Kokorev warehouses included in the list of cultural heritage objects was proposed. 
 Conclusion: the implementation of the proposed option for the reconstruction of the platform park of the St. Petersburg-Glavny station will allow, without the need for reconstruction of the locomotive facilities and technical parks, partially preserve the warehouses of the Kokorevs included in the list of cultural heritage sites.

Stochastic Excitation-Incorporated Seismic Fragility Assessment Using Monte Carlo Simulations

Structures are susceptible to damage from natural disasters like tornadoes, floods, and seismic events. A resilient structure can withstand such damage and ensure cost-effectiveness. Therefore, accurately assessing the probability of structural failure is imperative for structural designers. This study employs an innovative fragility methodology to assess seismic damage in structures. In comparison to conventional fragility approaches, this method is cost-effective, universally applicable across various seismic sources, and highly precise. Specifically, this method involves the generation of artificial seismic records using the point-source stochastic seismological model and Monte Carlo simulation method. These synthetic seismic records offer distinct advantages when compared to the seismic data collected from real earthquakes at recording stations, such as the ability to adjust the epicentral distance of the synthetic waves as needed. Therefore, this approach enables a comprehensive analysis of structural responses under seismic waves characterized by different attributes. For example, the influence of different seismological parameters such as wave magnitude and epicentral distance are well studied and compared. The advanced finite element software, OpenSees, serves as the computational platform for examining how structures react to diverse seismic waves. The research findings suggest that, compared to traditional methods, utilizing OpenSees can significantly enhance computational efficiency. Furthermore, the methods employed introduce a novel technique for factoring in wave magnitudes and distances during the calculation of structural seismological responses/fragility. This innovation holds significance for the development of next-generation structural resilience designs.

Review and Assessment of Fatigue Delamination Damage of Laminated Composite Structures.

Fatigue delamination damage is one of the most important fatigue failure modes for laminated composite structures. However, there are still many challenging problems in the development of the theoretical framework, mathematical/physical models, and numerical simulation of fatigue delamination. What is more, it is essential to establish a systematic classification of these methods and models. This article reviews the experimental phenomena of delamination onset and propagation under fatigue loading. The authors reviewed the commonly used phenomenological models for laminated composite structures. The research methods, general modeling formulas, and development prospects of phenomenological models were presented in detail. Based on the analysis of finite element models (FEMs) for laminated composite structures, several simulation methods for fatigue delamination damage models (FDDMs) were carefully classified. Then, the whole procedure, range of applications, capability assessment, and advantages and limitations of the models, which were based on four types of theoretical frameworks, were also discussed in detail. The theoretical frameworks include the strength theory model (SM), fracture mechanics model (FM), damage mechanics model (DM), and hybrid model (HM). To the best of the authors' knowledge, the FDDM based on the modified Paris law within the framework of hybrid fracture and damage mechanics is the most effective method so far. However, it is difficult for the traditional FDDM to solve the problem of the spatial delamination of complex structures. In addition, the balance between the cost of acquiring the model and the computational efficiency of the model is also critical. Therefore, several potential research directions, such as the extended finite element method (XFEM), isogeometric analysis (IGA), phase-field model (PFM), artificial intelligence algorithm, and higher-order deformation theory (HODT), have been presented in the conclusions. Through validation by investigators, these research directions have the ability to overcome the challenging technical issues in the fatigue delamination prediction of laminated composite structures.

A Novel Physics-Informed Hybrid Modeling Method for Dynamic Vibration Response Simulation of Rotor–Bearing System

For rotor–bearing systems, their dynamic vibration models must be built to simulate the vibration responses that affect the safe and reliable operation of rotating machinery under different operating conditions. Single physics-based modeling methods can be used to produce sufficient but inaccurate vibration samples at the cost of computational complexity. Moreover, single data-driven modeling methods may be more accurate, employing larger numbers of measured samples and reducing computational complexity, but these methods are affected by the insufficient and imbalanced samples in engineering applications. This paper proposes a physics-informed hybrid modeling method for simulating the dynamic responses of rotor–bearing systems to vibration under different rotor speeds and bearing health statuses. Firstly, a three-dimensional model of a rolling bearing and its supporting force are introduced, and a physics-based dynamic vibration model that couples flexible rotors and rigid bearings is constructed using multibody dynamics simulation. Secondly, combining the simulation vibration data obtained using the physics-based model with measured vibration data, algorithms are designed to learn vibration generation and data mapping networks in series connection to form a physics-informed hybrid model, which can quickly and accurately output the vibration responses of a rotor–bearing system. Finally, a case study on the single-span rotor platform is provided. By comparing the signal output by the proposed physics-informed hybrid modeling method with the measured signal in the time and frequency domains, the effectiveness of proposed method under both constant- and variable-speed operating conditions are illustrated.