Dynamic Model Simulation Research Articles

Coarse-grained molecular dynamic model and wettability simulation of graphite materials

Although progress has been made in high-performance computing, there are still limitations on temporal and spatial scales of molecular dynamic calculations. A major issue in molecular dynamic (MD) simulations is the computational cost, and coarse-grained methods can save computational costs and accelerate calculations by reducing the degrees of freedom in the system. This method takes a selected group of representative atoms in the atomic microstructure as a bead and uses the proportional relationship of atomic scale atomic potentials in MD simulation to define the interaction between beads and solve the motion equation of beads. This article proposed a coarse-grained potential for graphite based on the modification of Airebo potential, with an n3: 1 mapping, and established a corresponding n3: 1 coarse-grained model, where one bead represents the number of n3 atoms. The results indicated that the coarse-grained model well reflected the basic thermal and mechanical properties of graphite. In addition, this article also proposed a coarsening method for the Lennard–Jones (L–J) potential function parameters and established a coarse-grained wetting model with n = 2. The results indicate that the coarse-grained wetting model can effectively predict the wetting performance of copper droplets on graphite in only 60% of the time using the all-atom model. The coarsening potential function and model proposed in this article are also applicable to graphite with rough surfaces. It can be anticipated that coarse-grained molecular dynamics methods will have more applications in the future, as they can handle large-scale calculations more quickly.

Seeking a pathway towards a more sustainable human-water relationship by coupled model – From a perspective of socio-hydrology

It is essential to systematically consider social, economic, and natural endowments in managing and allocating water resources. However, few studies have comprehensively quantitatively evaluated the allocation of regional water resources from a socio-hydrology perspective and provided recommendations. To explore this research gap, we have constructed a tightly coupled framework that integrates system dynamics models and optimization algorithms to carry out an innovative redistribution of water resources in Shaanxi Province. The system dynamics model simulation results showed that the error was almost always within 10% over the research period, indicating robust simulation capability and laying a solid foundation for subsequent model coupling. The coupled model achieves convergence in approximately 30 generations by formulating the optimization problem with four individual objectives. Optimizing four objectives concurrently results in convergence around the 150th generation. The optimized Pareto solution sets visually demonstrate the trade-offs between different objectives. In the optimized water allocation schedule, the water consumption in Yulin exhibits a change of 1.22 ×108m3, reflecting the most significant optimization effects on agricultural and domestic water allocation. The results indicated that the comprehensive Gini coefficient typically ranged between 0.2 and 0.3. Over the period from the year 2010–2021, the Gini coefficient exhibited a declining trend, signifying a positive trajectory in water resource allocation throughout the research period and a high level of fairness. The annual total green WF of grain in Weinan was the highest at 14.26 ×108m3, followed by Xianyang at 9.52 ×108m3, and the lowest in Tongchuan at 0.54 ×108m3. The annual average amount of blue WF of grain is the highest in Hanzhong, at 11.33 ×108m3, followed by Weinan at 9.60 ×108m3, and the lowest in Tongchuan at 0.14 ×108m3. The coupled framework proposed in this study exhibits significant innovation, scalability, and practical efficiency. It can inspire future research and decision-making and holds the potential for application in other regions.

Numerical and experimental study on the performance of a stabilising turbine inside a seed distribution device

A design was proposed for a seed turbine installed within the distribution device to reduce the influence of surface slope variations on the uniformity of seeding mass at each row. Through a comparative analysis based on the computational fluid dynamics (CFD) 6 degrees of freedom (DOF) dynamic mesh model simulation and the bench test, the influence of five different stabilising turbines on airflow distribution performance was investigated. The type Ⅰ stabilising turbine, characterised by acute inlet and outlet angles, exhibited a smaller vortex region at the blade inlet and improved the conveying and mixing performance of the seed. A CFD 6DOF simulation experiment was conducted to investigate the influence of the type I stabilising turbine on the airflow field distribution. As the number of blades increased from 4 to 10, the stability and uniformity of the conveying airflow distribution were enhanced at the turbine outlet. Simulations using a comprehensive performance test platform of the planter evaluated the influence of stabilising turbines with different numbers of blades on uniformity during field operations at varying surface slopes. When the angles of the front-rear and lateral one-way oscillation combination, and the front-rear and lateral reciprocating oscillation combination varied within the range of −5°–5°, the stabilising turbine with 8 blades exhibited the smallest uniformity coefficient of variation of the seeding mass at each row. The values ranged from 4.1 % to 5.8 % for rapeseeds and from 3.8 % to 5.0 % for wheat seeds.

Application of the method of lines to the wave equation for simulating vibrating strings

This paper presents simulations of continuous dynamic models of vibrating strings for several different instruments: a guitar, a piano and a violin. The basis for all three models is the wave equation and is differentiated by the initial and boundary conditions imposed. The models are implemented as part of a Graphical User Interface. The simulations are presented as animations that are conveyed in the paper as a sequence of vibrating string profiles for different times. This paper promotes the idea that using music generation as a framework for teaching dynamics makes the teaching of dynamics a more engaging process. A case is made that there is value in solving the wave equation numerically using the method of lines rather than looking for analytical solutions. The reason for this is the mathematics of the method of lines is simpler to understand than the techniques used to derive analytical solutions to partial differential equations. The numerical approach is also more easily extended to a more sophisticated model for a vibrating string that might include energy dissipation and the stiffness properties of the string.

Industrial robot arm dynamic modeling simulation and variable-gain iterative learning control strategy design

Industrial robot arm dynamic modeling simulation and variable-gain iterative learning control strategy design

Study on the overall performance of e-waste dismantling industry polluted cultivated land utilization from a holistic view

The utilization of heavy metal-organic polluted cultivated land caused by the e-waste dismantling industry was affected by multi-dimensional factors. Thus a comprehensive evaluation of these multi-dimensional impacts was necessary for the technical selection and solution of cultivated land utilization. This study attempted to conduct a total benefit simulation analysis on the redevelopment of polluted cultivated land, which was of great significance to decision-making. With a systematic framework designed including the casual relations between components, a system dynamics model was constructed to simulate the technological, economic, and ecological benefits of different polluted cultivated land-used modes, along with which a questionnaire was designed to investigate and analyze the associated social effects. Based on these, the total benefits of the land-use mode were evaluated and optimized within the framework of the “technological-economic-ecological-social” evaluation system. This study included microscale, mesoscale, and macroscale, with multi-dimensional and complex influencing factors, and had advanced research value. The results of the system dynamics model simulation showed that remediation plants played a decisive role in pollutants removal. The flower industry had the highest net present value, but its ecological performance was poor. The overall analysis showed that the scenario of utilization after remediation had the highest performance score, which was attributed to high pollutant removal, low cost, and high carbon sink. This study was meaningful for providing research ideas of comprehensive benefits of polluted cultivated land utilization and also helpful for decision-making. This paper also provided research ideas for other industries such as contaminated site remediation and sewage sludge treatment.

Dynamic Modelling, Simulation, and Sensitive Analysis of Lead Removal in a Fixed-Bed Adsorption Column using Waste-Based Materials

Abstract This study focuses on dynamic modelling and numerical simulation of lead removal from contaminated water using a fixed-bed adsorption column packed with waste-based adsorbents. The pressing need for efficient and sustainable water treatment methods, particularly for heavy metal removal, underscores the significance of this research. Lead contamination in water sources poses severe health risks, necessitating the development of effective removal strategies. The present investigation centres on a comprehensive mathematical model that considers critical parameters, including the column’s physical dimensions, flow rate, initial lead concentration, adsorption rate constant, and adsorbent density. This model is expressed as a partial differential equation (PDE) describing the temporal and spatial evolution of lead concentration along the fixed-bed column. To solve the PDE, the method of lines, a powerful numerical technique that discretises the spatial domain and handles the resulting system of ordinary differential equations (ODEs) using an adaptive solver, is employed. Following that, the effect factors of the simulation process are evaluated by sensitive analysis approach. Simulations are conducted to elucidate the intricate dynamics of lead removal over time and column height. The numerical approach enables the prediction of lead concentration profiles within the column at various time intervals, providing crucial insights into the behavior of the adsorption process.

Impedance Controller Design and Dynamic Solution of The Manipulandum

This article explains the dynamic solution of the manipulandum that interact with the human upper arm, controller design, model simulation and simulation results. Manipulandum design in this field are used in human-machine interaction experiments to understand human motor learning skills. While the subject of experiments is handled in the field of medicine, appropriate manipulandum design is the subject of the engineering field. In this article, the engineering qualities of the device were evaluated, its mathematical model obtained, dynamic model simulation made and control elements were examined, but the experimental use of this device, which is serve medical science were not discussed in this context. In the literature review; The manipulandum have a 2-dof, 5-link closed chain structure that moves in the horizontal plane, their movement is provided by 2 actuators, their interaction with the human upper arm is made with a fixed joystick (end-effector) on the 2nd link, their dimensions are smooth and compatible with the human upper arm. It is understood that the manipulandum must be of a size that can safely interact with the human arm. A conceptual design was made for the manipulandum and the movement parameters of the manipulandum were obtained by creating a kinematic model accordingly. While creating the dynamic model of the system; It is accepted that the manipulandum moves in the horizontal plane, therefore there is no effect of gravity, there is no spring, damper or similar potential energy source in the system, and there is heat loss due to friction. The dynamic model obtained with the Euler Lagrange Method (ELM) was compared with the system model obtained with the Simulink Simscape Multibody (SSM) tool in the Simulink environment; The consistency of model parameters (friction coefficients, moment of inertia, etc.) was mutually checked. Since human-manipulandum interaction requires force control, an impedance controller has been designed for the system dynamics, instead of classical controllers. The success of the controller on both the ELM dynamic model and the model created in SSM was examined and the results were evaluated. As a result of the simulations; It is understood that in order to achieve meaningful position and force control, there must be a proportional magnitude relationship between the torques applied to the model by the actuators and the force applied to the end-effector.

Enhanced response of thermospheric cooling emission to negative pressure pulse

Nitric oxide (NO) emission via 5.3 µm wavelength plays dominant role in regulating the thermospheric temperature due to thermostat nature. The response of NO 5.3 mm emission to the negative pressure impulse during November 06–09, 2010 is studied by using Sounding of Atmosphere by Broadband Emission Radiometry (SABER) observations onboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite and model simulations. The TIMED/SABER satellite observations demonstrate a significant enhancement in the high latitude region. The Open Geospace General Circulation Model (OpenGGCM), Weimer model simulations and Active Magnetosphere and Planetary Electrodynamics Response Experiment measurements exhibit intensification and equatorward expansion of the field-aligned-currents (FACs) post-negative pressure impulse period due to the expansion of the dayside magnetosphere. The enhanced FACs drive precipitation of low energy particle flux and Joule heating rate affecting whole magnetosphere–ionosphere–thermosphere system. Our study based on electric fields and conductivity derived from the EISCAT Tromsø\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\o }$$\\end{document} radar and TIEGCM simulation suggests that the enhanced Joule heating rate and the particle precipitations prompt the increase in NO cooling emission.

Flight control design for a hypersonic waverider configuration: A non-linear model following control approach

AbstractDLR is currently investigating the potential of hypersonic flight systems in the context of different mission scenarios. One configuration type of higher interest for civil and military purposes is the hypersonic glide vehicle (HGV). Such HGVs operate over broad flight envelopes and pose complex flight dynamic characteristics. This article presents DLR’s generic hypersonic glide vehicle 2 (GHVG-2) and proposes an integrated non-linear flight control architecture that is based on the idea of the non-linear dynamic inversion and non-linear model following control methodologies. The proposed control scheme is designed to sufficiently and robustly handle the system dynamics of the over-actuated flight vehicle. The approach is first discussed, and the performance of the suggested control laws is later investigated via simulations of a high-fidelity non-linear flight dynamic model in the nominal case and under the presence of parametric uncertainties. The presented results demonstrate that the proposed NMFC approach provides benefits for the robust control of the regarded hypersonic system.

Dynamic Constitutive Model and Numerical Simulation of S32760 Duplex Stainless Steel Based on Dislocation Theory

Background: To describe the complex mechanical behavior of S32760 duplex stain-less steel under high strain rate and high-temperature loading conditions. Objective: The constitutive model of S32760 duplex stainless steel suitable for high strain rate was constructed from the micro-scale. Methods: Based on the theory of dislocation dynamics, the effects of different strain rates and strains on the plastic deformation of ferrite and austenite were analyzed, and the thermal stress term and non-thermal stress term of ferrite and austenite phases were coupled. Results: The simulation results of the model show that the S32760 dual-phase constitutive model has a high degree of fit with the experimental data at high strain rates. Conclusion: Compared with the classical J-C model, the results show that the constitutive model of this patent has more accurate predictability than the J-C model in describing the mechanical behavior of duplex stainless steel in the high strain range of 5000s-1 to 10000s-1.

Dynamic Model on Palm Oil Production Capacity Using Variable CPO Stock for Biofuel Production

The role of biofuel for running diesel power plants is therefore indispensable for compensating various renewable plants with fluctuating output, maintaining stability to the overall power system. For expanding biofuel production, keeping the rate of investment in CPO mills is critical, as it is often driven by CPO business profit. The seasonal nature of palm-oil plantation harvest directly influences CPO production behaviour. This research investigates system dynamics model simulation for CPO production system, indicated by the feedback loop from market demand, hence influencing the daily (or monthly) CPO production to provide revenue stream to the business. Subsequently, it influences the rate of investment for increasing production capacity, forming the dynamic hypothesis for the system. The model was developed using endogenous variables, while trying to reduce the number of external inputs required to run the simulation. By substituting the price variable with the level of CPO stock at the national level, less uncertainties would affect the system such as price instability situation. Feedback signal from the level of CPO stock was utilized to control the simulated amount of CPO production, as well as the rate of re-investment for expanding the country’s production capacity. Model simulation results was able to reproduce the system behaviour for capacity increase, to meet CPO market demand. The model structure could be further replicated for efficiently developing the dynamic model for basic commodity production, where the rate of commodity production would not influence the overall market demand (decoupling of production rate from global market)

Dynamic Modeling and Optimization Analysis of Rigid–Flexible Coupling Manipulator Based on Assumed Mode Method

Lightweight robotic arms are one of the main technologies to improve the working performance of robotic arms in the future. Focusing on the spatial vibrations issue brought about by the light-weighting of a space robotic arm in this paper, a rigid–flexible coupling dynamics model of a space robotic arm system was established based on the assumed mode method and Lagrange method. Based on the lightweight flexible robotic arm structure, a comparative analysis of the first four mode functions was conducted under different fixed constraints and physical properties to determine the mode order that matches the simulation analysis of this robotic arm, thus, further simplifying the rigid–flexible coupling dynamics equations of the system. The overall rigid model and simplified dynamic model of the robotic arm system were solved by using MATLAB, resulting in a motion trajectory of the flexible arm end in space. The three-dimensional model was validated and simulated using virtual prototype technology under the same joint inputs as the model in MATLAB. The simulation results demonstrated that the trajectory of the end of the flexible arm was basically the same between simplified dynamics model simulation and virtual prototype simulation, and the maximum deviation of the end trajectories of the flexible connecting rods [Formula: see text] and [Formula: see text] was less than 18[Formula: see text]mm and 58[Formula: see text]mm, respectively. Meanwhile, the trajectory trend of the end of the flexible arm in the two aforementioned models was the same as the simulation results of the ideal model (overall rigid model). The above conclusions can verify the correctness of the mathematical model of dynamics obtained from the calculations in this paper. In addition, the research data showed that the maximum vibration deviation of the flexible arm was stabilized within a certain value range under different joint inputs, and this research also provided theoretical support for the late vibration suppression control of the spatial rigid–flexible coupled robotic arm.

The influence of asymmetric rail cant on rail corrugation in a small-radius curve section

A suitably designed rail cant can improve the wheel-rail alignment, effectively reduce the wheel-rail contact pressure and reduce the wheel-rail wear. However, the rail base cant has rarely been specifically designed for suppressing rail corrugation. Furthermore, no studies have yet been conducted on using different inner and outer rail cants in small-radius curve sections from the perspective of suppressing rail corrugations and wear. In this study, the growth rate index of rail corrugation is obtained by combining an impact hammer origin admittance test and a coupled vehicle-track multi-body dynamic model simulations. The wear depth of rail surface is obtained by combining a three-dimensional transient wheel-rail rolling contact model and Archard wear theory. From the overall perspective of preventing rail corrugation and slowing down rail wear, based on the multi-objective optimization using a particle swarm optimization algorithm, the optimal configuration of inner and outer rail cants in a small-radius curve section were determined as 1/22 and 1/40, respectively, which provided effective suppression of rail corrugation initiation and further development of rail wear.

Enhancing the Intellectual Capital of Research and Development Centres using Business Intelligence: A System Dynamics Approach

AbstractThis study employs system dynamics simulation to examine the scenarios and policies aimed at enhancing the intellectual capital of R&D centres. Through an in‐depth review of the relevant literature, such as thematic analysis, along with an examination of regulations and expert interviews and focus group discussions as well, the dimensions, variables and measurement indicators associated with Intellectual Capital and Business Intelligence, were identified. The dynamic relationships among these variables are then modelled, and the model's behaviour is simulated. By implementing two scenarios, namely reducing government financial support and increasing the competitive environment, the simulation results indicate that the enhancement of informational and relational capital will improve structural capital and increase business intelligence. Over ten years of simulation, the centre's dedicated revenue will grow by more than 150%. The proposed dynamic modelling and system behaviour simulation can serve as a basis for setting an intellectual capital framework in R&D centres, particularly in developing countries.

Groundwater Management in Coastal Area of Batang Regency to Anticipate Sea Water Intrusion

Of the water sources that exist on earth, almost all of human’s daily water needs such as drinking, bathing and washing are sourced from groundwater. Uncontrolled extraction of groundwater can cause various impacts on the environment, such as lowering of the groundwater level and seawater intrusion. Efforts to manage groundwater need to be carried out so that its availability is always maintained. The initial step of this effort is to formulate a management model as a basis for policy determination. For this reason, in this study a dynamic modeling simulation was carried out using dinamic program. The results of the research show that the priority for groundwater management efforts in the coastal area of Batang Regency is to reduce the use of groundwater for the domestic sector which can be done through saving groundwater use or by increasing the capacity of the local water company. Besides that, management through artificial recharge by making infiltration wells or biopore holes is also effective in maintaining the availability of groundwater in this area.

Thermal performance analysis of a novel Conical-Cylindrical-Conical cavity receiver for a Scheffler concentrated solar system

The thermal efficiency of a receiver is a critical component of the point focusing concentrated solar system, significantly impacting the overall system efficiency. A thermal performance analysis of the developed novel Conical-Cylindrical-Conical cavity receiver is carried out for the enhancement of its efficiency. The analysis involves varying aspect ratios (0.8, 1, and 1.2) of the receiver utilizing Computational Fluid Dynamics with ANSYS (Fluent 2023R1) and the discrete ordinates modeling technique. The simulation results reveal a peak thermal efficiency of 80.9 % for the receiver at mass flow rate of 0.035 kg/s. The experimental validation is performed using a 16 m2 concentrator solar Scheffler dish under real outdoor conditions in a hilly terrain of India. The average percentage error between the experimental results and the Computational Fluid Dynamics model simulation, is found to be 0.52 %.The results of study highlights the significant impact of design and aspect ratio on the thermal efficiency of the cavity receiver. This study is the first investigation into the aspect ratio of the novel Conical-Cylindrical-Conical cavity receiver for point focusing concentrated solar system, providing valuable insights for further research and industrial applications worldwide.

Dynamic Performance Optimization of Monorail Rapid Transit Formation Vehicles Based on Improved Artificial Potential Field Algorithm

This paper presents a new type of monorail rapid transit vehicle, which can operate in formation. In order to optimize the dynamic performance of the formation vehic-les when passing through the small radius curve, this paper first analyzes the structure of the new monorail rapid transit vehicle, and establishes the vehicle dynamic model and multi-body dynamics simulation model. Then the improved artificial potential field algorithm is used to build the formation vehicle operation controller. Finally, the dynamic performance evaluation index of the new mono-rail rapid transit formation vehicle is formulated, and the formation vehicle passing through the small radius curve scene is simulated. The simulation results show that the controller of the formation vehicle with dynamic optimi-zation control can effectively optimize the load transfer coefficient of running wheels, unbalanced centrifugal acce-leration and roll angle of vehicle body when passing thro-ugh the curve. Through this control method, the dynamic performance of formation vehicles passing through small radius curve lines can be optimized.

Simulation and prediction study of artificial intelligence education dynamics model for primary and secondary schools

Simulation and prediction study of artificial intelligence education dynamics model for primary and secondary schools

Application of Dynamic Model for Designing Zero Runoff System to Control Erosion in Cocoa Fields

Land degradation in cocoa plantations is mainly caused by surface runoff erosion. Surface runoff can be reduced by applying a Zero Runoff (ZRO) system. This system effectively reduces runoff when its size sufficiently infiltrates all surface runoff. This study aims to determine the size, dimensions, and location of a ZRO system that effectively increases infiltration and prevents surface runoff. The size and dimensions of the system were designed using a water balance approach, where all surface runoff is collected in the ZRO system and then infiltrated. Surface runoff was calculated using the Soil Conservation Services (SCS) method. The potential infiltration rate is a function of the soil's saturated hydraulic conductivity and the system's surface area. The saturated hydraulic conductivity of the soil was determined using the falling head method. The size and dimensions of the system were determined through model simulation based on field physical condition data using a dynamic model. The research results showed that the size and dimensions of the system depend on the amount of rainfall, the area of the catchment area, and the saturated hydraulic conductivity of the soil. From the dynamic model simulation, all surface runoff will be infiltrated if the dimensions of the zero runoff system are 1 x 1 x 0.5 m. This size can accommodate a water volume between 0 – 0,006 m3, so with a system depth of 1,000 mm, there is no surface runoff.