Search

Extensive reviews and cross-comparison studies are essential to analyze the emerging developments in a specific field of research. In the past decade, hydrocarbon exploration and exploitation from the shale reservoirs have been the most discussed and researched area around the globe. A dramatic development in shale formations became the game-changer, especially in the US. On the other hand, Artificial Intelligence (AI) and Machine Learning (ML) are playing an important role in the rapid development in all the industries through automating most of the routine operations. The oil industry is also getting equal benefits of AI and ML for the reservoir development planning and its operational accuracy through a series of automated systems. For the field development, computerized static and dynamic simulation models are generated based on several Petrophysical and Geomechanical properties gathered through different resources that are quite a time taking and expensive. AI and ML have made this process much easier, faster, and economical by means of learning through uncounted experiences from already explored and developed reservoirs, their rock properties, and the cross-ponding fluid flow behavior under different circumstances and hence, predicts accordingly. This article provides a comprehensive literature review in the area of AI and ML application to model Petrophysical and Geomechanical properties using different approaches and algorithms. Also, a systematic publication counts in each field of subject study per year in different literature databases are presented that infect reflects the trending interest in this subject. Finally, multiple AI and ML techniques are discussed in detail that has been tested in the last decade for the sake of achieving more accuracy in Petrophysical and Geo-Mechanical simulation models.

This paper presents a dynamical analysis of a tethered aerostat using a multibody simulation tool called SimscapeMultibody™. Tethered aerostats are lighter than air vehicles that float in the air and are connected to the ground through the tether. Atmospheric winds are a source of disturbance to the aerostat. The wind produces drag force that causes the aerostat to displace from its mean position. This phenomenon is called blow-by. Solving the mathematical model of the motion dynamics with time step is the conventional method used for simulating the flight dynamics of the aerostat. This paper discusses the application of Simscape Multibody™ for the three-degrees-of-freedom flight dynamic simulation of spherical tethered aerostat. Simscape Multibody™, an extension of MATLAB®/Simulink, is a multibody modeling tool in which physical bodies and their interactions have to be defined to simulate the dynamics. The mathematical model of the defined system is automatically generated by the SimscapeMultibody™ solver, and the system dynamics is simulated. The simulation of dynamics using multibody modeling tools provides high fidelity simulation for the tethered aerostats.

Hinged booms are widely used in astrophysics missions; however, the trajectory and deployment velocity are difficult to control because they are usually driven by springs, which limits their application in narrow spaces. Thus, a novel hinged boom is highly required to achieve motion controllability. Through an equivalent substitution between the cable drive loop and the binary link in topology, a type synthesis method for the cable-driven single-degree-of-freedom chain is proposed based on the single-open-chain (SOC) adding method. According to the configuration design, a novel cable-driven hinged boom is proposed, aiming to achieve boom synchronism. Then, to preload easily, a method that preload is applied and measured at the cable ends is adopted and the relationship between the initial preload and the target preload is deduced. By analyzing the distribution of cable tension, a new stiffness model is proposed thus a stiffness equation is obtained. Finally, the dynamic simulation analysis and zero-gravity deployment experiment of the hinged boom is carried out to verify its reliability. This research provides a new way for the type synthesis of cable-driven single-degree-of-freedom chain and a new model for analyzing cable-driven stiffness. Moreover, the novel cable-driven hinged boom obtained in this study can be well-applied in the field of aerospace.

This paper presents the study of binary component analysis subjected to distillation process using Aspen Plus. Binary components namely Isopropyle alcohol and water were considered for the study and their characteristics are analyzed at certain temperature and pressure. Aspen Plus provides virtual exposure of physical process, gives quantitative measure of mole fraction of liquid phase, vapor phase with changes in temperature, pressure and activity coefficients. Steady state and dynamic simulation results depicts the behavior of the system and enables the user to understand how the system reacts in virtual environment, to realize the system behavior in real-time environment.

To study the internal flow characteristics of the photovoltaic pump under the transient change of solar radiation, the simulation algorithm of the photovoltaic pump system was established by MATLAB/Simulink and CFD for the first time and the results were validated by the test. Firstly, the change rule of pump flow rate and rotation speed under transient solar radiation was obtained by Simulink. Then the results of the change rule were transformed into the boundary condition of CFD by CEL function and the transient flow field in the photovoltaic pump was obtained. The internal flow characteristics and pressure pulsation in the pump were analyzed when the solar radiation increases or decreases transiently. The results demonstrate that the numerical calculation can provide accurate prediction for the characteristics of internal flow in the pump. The numerical results are closed to the experimental results, the minimum error of pressure is 0.93% and the maximum error is 1.78%. When the solar radiation increases transiently, the low pressure area at the impeller inlet gets larger obviously and the jet-wake at the impeller outlet becomes more obvious. The pressure pulsation in the impeller gradually increases and becomes stable after 0.6 s. The pressure from the impeller outlet to the guide vane outlet is stable at 123 kPa. When the solar radiation decreases transiently, the pressure in the impeller takes 1.6 s to be stable. Larger pressure pulsation occurs from the impeller outlet to the guide vane inlet and the maximum differential pressure is 10 kPa. Compared with the transient increase of solar radiation, the pressure in the impeller takes over 0.2 s to stabilize when the solar radiation transient decreases. Meanwhile, the results in this paper can provide references for other transient characteristics research. Highlight First, the relation between pump flow rate and rotation speed under transient solar radiation was obtained by Simulink. Then the results from Simulink were transformed to be the boundary condition of CFD by CEL function. The internal flow characteristics and pressure pulsation in the pump were analyzed under the instantaneous increase or decrease of the solar radiation.

In order to improve the accuracy of dynamic detection of wind field in the three-dimensional display space, system software is carried out on the actual scene and corresponding airborne radar observation information data, and the particle swarm algorithm fuzzy logic algorithm is introduced into the wind field dynamic simulation process in three-dimensional display space, to analyze the error of the filtering result in detail, to process the hurricane Lily Doppler radar measurement data with the optimal adaptive filtering according to the error data. The three-dimensional wind field synchronous measurement data obtained by filtering was compared with three-dimensional wind field synchronous measurement data of the GPS dropsonde in this experiment, the sea surface wind field measurement data of the multi-band microwave radiometer, and the wind field data at aircraft altitude.

In this article, a new torque sharing function (TSF) method is proposed for torque ripple reduction in switched reluctance machines (SRMs). The proposed TSF achieves lower current tracking error by establishing a new current reference generation strategy. The phase current reference is first derived from the torque command using offline calculations and also from the phase current response that is obtained from the dynamic model of the SRM. Then, an optimization problem is formulated to shape the current reference for the objective of minimizing the torque ripple and copper losses, while maintaining the required average output torque at the given operating speed. The dynamic simulation of the SRM model is also utilized in the optimization problem. Compared to the existing conventional and optimization-based TSFs, the proposed TSF exhibits lower current tracking error due to the consideration of the current dynamics. Better torque–speed performance with improved average torque and reduced torque ripple is also obtained, especially during commutation. Simulations and experiments under different operating conditions are carried out to verify the proposed TSF method.

An explicit dynamic simulation of the vertical crash of a regional airliner’s middle fuselage section has been conducted to investigate its crashworthiness. The simulation result shows that there a...

The transparent elements of the building envelope have a crucial role not only in term of heat and mass transfers control, but also for natural light penetration, sound insulation, thermal and visual comfort of the occupants and their health. Among passive technologies, the light shelves could be architectural solutions for improving daylight penetration and for controlling thermal loads. The available research papers usually focus on one aspect. For this reason, the aim of the present study is to analyse the application of the light shelves with multidisciplinary approach and thus, taking into account: daylight, electricity for lighting, cooling and heating needs and thermo-hygrometric comfort. The case study is a real dormitory building placed in Athens and subject to a deep energy renovation toward the nearly zero energy building target. EnergyPlus, by means of DesignBuilder interface, has been used as dynamic simulation tool. Among ten different configurations, the optimal one turns out to be the internal horizontal light shelf placed at 50 cm from the top of the window with a depth of 90 cm or 60 cm. It has been found that in some cases the reduction of electricity for lighting cannot balance the variation in heating and cooling needs.

The tether-net system is a promising technique for active debris removal. The capture process of a tether-net system for debris exhibits the nonlinear dynamics of very high dimensions and requires the dynamic simulation of high accuracy and efficiency in the design stage. This paper presents an integrated approach of both method of discrete elastic rods and algorithm of energy-conserving integration for the above purpose. The study shows that the method of discrete elastic rods is more suitable for modeling the extremely flexible threads of a woven net than the slender beam elements with C1 continuity. Besides, the energy-conserving integrator embedded in the present approach well conserves the total energy, and does not produce any numerical dissipations. The paper gives three numerical examples, including the capturing process of a hexagonal tether-net system for a space target, to demonstrate the advantages of the present approach, as well as the influence of some initial control parameters on the deployment phase of the tether-net system.

The objective of this paper is to perform an in-depth feasibility analysis and dimensioning of a potential Environmental Control and Life Support System (ECLSS) and power system for a crewed lunar base at the lunar south pole. The analyzed ECLSS includes an In-Situ Resource Utilization (ISRU) reactor for oxygen resupply and a Regenerative Fuel Cell System (RFCS) as power supply during shadow phases. The co-dependencies and interactions between the ECLSS sub-systems themselves and with the environment are incorporated to achieve a holistic system analysis. We used a fixed ECLSS configuration based on the current NASA plans for a Moon base ECLSS with a fixed function-to-subsystem allocation. The performed trade-offs are then restricted within the design space, to e.g. resize tanks and individual subsystems instead of considering other possible subsystems. We chose this approach because the aim of this paper is to perform an in-depth system analysis of all related subsystems and their interaction with the environment instead of a top-level trade-off. The first step is the selection of a suitable landing site and the dynamic simulation of its lighting conditions over the investigated period of 1 year. We use a slope map with a resolution of 120 m per pixel, a Permanently Shaded Region (PSR) map with a resolution of 240 m per pixel and a digital elevation model with a resolution of 240 m per point, which is interpolated from a source with a resolution of 60 m per pixel and meshed with triangles by the Thermal Moon Simulator (TherMoS) tool in order to calculate illumination values. The requirements chosen for the candidate landing sites are a slope of less than 5° over a diameter of at least 1 km and having both a PSR and a Peak of Light (POL) in less than 10 km distance. We discuss the four most promising candidate sites in this paper and calculate initial energy storage system estimates to select two landing sites for further analysis. We derive a reaction kinetics model for the ilmenite hydrogen reduction ISRU process from literature data and incorporate it into a dynamic model with simulated lighting and thermal conditions to calculate heat losses to the environment and the required electrical energy for its operation. In addition, we use the derived model to analyze and compare different design options of the ISRU reactor with an Equivalent System Mass (ESM) based optimization approach to identify the optimal operating conditions. Using this approach, we found operating temperatures above 1150 K resulted in higher ESM values for the reactor than lower temperatures. For the Moon base, we combine an ISS ECLSS model and the ISRU reactor model. The state-of-the-art urine and water processing technologies achieve recovery rates of up to 98%. Hence, we expect the overall ECLSS including the ISRU reactor to have a water surplus when combined with a Sabatier reactor to process metabolic CO2 from the crew into methane and water. Therefore, the Sabatier reactor combined with an electrolyzer can potentially generate methane and oxygen as fuel for resupply missions. The system can achieve a theoretic fuel production of 4100 kg per year using this approach. Although the dynamic analysis showed that only 2588 kg could be produced per year because of the lean operating conditions of the Sabatier and its efficiency of below 100%. The produced oxygen and methane could reduce operating costs for the base by reducing the required fuel resupply. Based on the power demands of the other subsystems and the available solar power and shadow duration at the selected landing site, we dimensioned the RFCS and estimate the required mass for it to 19,500 kg. Which is less than half the mass required if lithium batteries are used. The overall system requires resupply of approximately 6580 kg per year for a crew of six. The dynamic analysis of the system showed that the initial mostly steady state sizing approach can be optimized and relevant system parameters can be reduced by more than 15%.

The increasingly complex AC/DC network as a result of the massive integration of wind farms manifests the significance of a comprehensive transient study. In this work, the wind turbine (WT) and the DC grid are modeled in detail for the electromagnetic transient (EMT) simulation to maximize its fidelity, whilst the AC grid transient stability is analyzed by dynamic simulation (DS). An interactive EMT-DS interface is thus introduced to enable their concurrency and subsequently form a co-simulation. The CPU which is dominant in system study faces a tremendous challenge in handling a great number of components albeit they exhibit homogeneity. The many-core graphics processing unit (GPU) featuring massive parallelism is therefore exploited and following the definition of an adaptive computing boundary, a flexible heterogeneous sequential-parallel processing architecture is proposed for efficient analysis of the wind farm-integrated AC/DC grid. Topological reconfiguration of WTs is specifically carried out to reduce the numerical order whilst enhancing system homogeneity that enables the GPU to thoroughly utilize its peculiar property of single-instruction multiple-thread (SIMT) compute paradigm. Consequently, significant speedups can be attained by the proposed computing framework over pure CPU computation, while its accuracy is validated by the commercial EMT and dynamic security analysis tools PSCAD/EMTDC and DSATools, respectively.

Historically, distribution system planning studies mainly focused on steady state and quasi-steady state analysis, with limited attention paid to dynamic analysis. This paper develops three-phase, electromechanical models for both grid-forming and grid-following inverters, and integrates them into an open source, three-phase distribution network solver, thereby enabling dynamic simulation of large-scale, three-phase unbalanced distribution systems with high penetration of inverter-based DERs. The proposed inverter models are validated against electromagnetic simulation and field test data from the CERTS/AEP microgrid testbed, and simulated in an islanded 5252 node distribution system in the GridLAB-D simulation environment. Simulation verifies the effectiveness of the proposed inverter models for large-scale distribution system analysis. Study results show that compared to traditional grid-following inverters, the high penetration of grid-forming inverters can improve the voltage and frequency stability of islanded distribution systems.

In this paper, we present a novel general framework grounded in the factor graph theory to solve kinematic and dynamic problems for multi-body systems. Although the motion of multi-body systems is considered to be a well-studied problem and various methods have been proposed for its solution, a unified approach providing an intuitive interpretation is still pursued. We describe how to build factor graphs to model and simulate multibody systems using both, independent and dependent coordinates. Then, batch optimization or a fixed-lag-smoother can be applied to solve the underlying optimization problem that results in a highly-sparse nonlinear minimization problem. The proposed framework has been tested in extensive simulations and validated against a commercial multibody software. We release a reference implementation as an open-source C++ library, based on the GTSAM framework, a well-known estimation library. Simulations of forward and inverse dynamics are presented, showing comparable accuracy with classical approaches. The proposed factor graph-based framework has the potential to be integrated into applications related with motion estimation and parameter identification of complex mechanical systems, ranging from mechanisms to vehicles, or robot manipulators., 23 pages

In order to comprehensively consider the dynamic behavior of vehicle system and the contact forces between wheel and rail, the vehicle-track coupling model is established considering the flexible wheelset and rail modal characteristics. Guyan reduction theory is introduced to reduce the degrees of freedom of wheelset and rail and to improve the calculation speed. Due to small axle load variation of freight wagon operating on the special line for the coal transportation, the vehicles with different speeds and wheel flat lengths, whether in empty or loaded conditions, are simulated and then the mapping relations between the flat lengths and wheel/rail impact force are obtained. Subsequently, the fitting functions for the empty and loaded vehicles are fitted to quantitatively detect the wheel flat by trackside equipment. The results indicate that the fitting function of empty vehicle has a better effect on predicting the flat length within 6% error since wheel/rail contact force of empty vehicle induced by wheel flat increases with the increase of flat length, while that of loaded vehicle presents a parabola variation trend at low speed and increasing trend at higher speed.

A secondary suspension configuration that integrates the Interconnected Hydro-Pneumatic Struts (IHPS) to the air spring system is proposed in this investigation for railway vehicles. Using the dynamic performance of IHPS, this suspension aims to provide smaller vertical supporting stiffness and larger anti-roll resistance compared to the traditional configuration, the air spring is connected to an emergency rubber spring in series with quite large stiffness. By replacing the rubber spring with IHPS, the proposed suspension configuration contributes to vibration absorption as well as anti-roll stiffness of the vehicle. The IHPS has two hydraulic cylinders installed in parallel to support the suspended mass. Each hydraulic cylinder has three oil chambers, and the oil chambers between the left and right struts are cross-connected through pipelines. Considering the oil compressibility and the vibration of liquid in the interconnected pipes, the mathematical model of IHPS is formulated and established in MATLAB. A multi-body dynamic railway vehicle model is built in SIMPACK, into which the IHPS is integrated through a co-simulation technique. Model validations on the IHPS are performed and its static and dynamic stiffness is examined. Numerical simulations show that the IHPS suspension reduces the vertical acceleration on the car body floor at a frequency between 1 and 3 Hz than the traditional air spring system with/without an anti-roll bar configuration. The vertical Sperling index of the vehicle using the IHPS suspension is smaller than that of the traditional suspensions, and it is more significant when the air spring deflates. However, the vertical acceleration with IHPS is larger than the traditional suspensions at 13∼55 Hz when the air spring deflates.

Dynamic analysis is an essential task in the geometry design of suspension systems. Whereas the dynamic simulation based on numerical software like Adams is quite slowly and the existing analytical models of the nonlinear suspension geometry are mostly based on small displacement hypothesis, this paper aims to propose a whole-range dynamic model with high computational efficiency for planar double wishbone suspensions and further achieve the fast optimal design of suspension geometry. Selection of the new generalized coordinate and explicit solutions of the basic four-bar mechanism dramatically reduce the complexity of suspension geometry representation and provide analytical solutions for all of the time varying dimensions. By this means, the running speed and computational accuracy of the new model are guaranteed simultaneously. Furthermore, an original Matlab/Simulink implementation is given to maintain the geometric nonlinearity in the solving process of dynamic differential equations. After verifying its accuracy with an ADAMS prototype, the presented whole-range model is used in the vast-parameter optimization of suspension geometry. Since both kinematic and dynamic performances are evaluated in the objective function, the optimization is qualified to give a comprehensive suggestion to the design of suspension geometry.

An experimental investigation and dynamic simulation of vertical falling-film LiBr/H2O absorption heat transformer systems have been reported in this paper. The established 20 kW experimental equipment was used to test the dynamic performance and verified the mathematical model. The experimental results show that there is a time delay between the input heat and output useful heat, and the time delay of the experimental results is 115 s. The simulated results show that the response time increases with increasing total solution mass and increases with decreasing solution mass flow rate. The temperature flow oscillations decrease with increasing total solution mass and decrease when the solution mass flow rate decreases. The response time of the absorption heat transformer is almost linearly related to the characteristic time of solution storage, which provides guidance for the operation and prediction. By adjusting the total solution mass and solution mass flow rate, theoretically the response time can be reduced to approximately 150 s. The temperature change range of the absorber outlet water can be controlled within 0.5 K by reducing the solution mass flow rate. The total solution mass and mass flow rate should be reduced, which can reduce temperature flow oscillations and shorten the time delay. The response time can be predicted by combining the experimental data and the linear relationship of the response time for any absorption heat transformer.

Rare Earth Elements (REEs) are essential for sustainable energy technologies. Techno-economic Assessments (TEAs) have been conducted to evaluate innovative approaches to recover REEs from waste streams. However, most TEA studies do not consider the price volatility of REEs, which raises concern over the reliability of the analysis in an unpredictable dynamic market. To address this shortcoming, a dynamic price model is proposed that adjusts REE price based upon supply-demand conditions. The dynamic market behavior is simulated and its effect on a TEA is examined via a case study. The results of the dynamic simulation indicate a growing trend of the market price for REE materials/products. Compared to a conventional TEA that does not consider price dynamics, a significant difference in economic performance metrics is identified from the dynamic TEA results. The proposed dynamic TEA method is not limited to a specific application and can provide insights for evaluating a broad range of technologies.

A solid oxide cell-based energy system is proposed for a solar-powered stand-alone building. The system is comprised of a 5 kWel solid oxide fuel cell (SOFC), a 9.5 kWel solid oxide electrolysis cell (SOEC), and the required balance of plant. The SOFC supplies: 1- building demand in the absence of sufficient solar power, 2- heat for SOEC in endothermic and standby modes. Thermal integration of SOFC and SOEC is implemented through a network of heat exchangers, combined with set of control algorithms. Two control strategies were implemented to actuate the SOFC in response to endothermic heat demands of SOEC by manipulating: 1- electric power, 2- fuel utilization. The results of dynamic simulation of system for two scenarios (sunny day and cloudy day) showed successful compliance of temperature constraints with both methods. Manipulation of fuel utilization, however, resulted in better system performance in terms of efficiency and H2 balance.

Numerical simulation is the key technique for large-scale power system analysis. Redistribution of global renewable power via international interconnections requires new simulation tools to study the interconnected systems with different nominal frequencies as a whole. This paper introduces an open-source simulation toolkit for electrical power systems (STEPS) hosted at Github. Its kernel is coded in C++ with major functions of power flow and electro-mechanical dynamic simulation. Flexible options are provided and configurable to improve power flow solution and dynamic simulation. Common devices and models are supported in STEPS for AC/DC hybrid system studies. The study of interconnected systems with different nominal frequencies is supported in STEPS for research of international interconnection. Application program interfaces are provided and wrapped with Python to enable high-level interfaces for general applications. STEPS is thread-safe, and parallel computation is supported in both kernel-level and task-level parallelization to accelerate simulation. It is portable and works on Windows and GNU/Linux platforms. Cases from small to large-scale systems are thoroughly tested to validate the toolkit with commercial packages as benchmarks.

In order to more accurately analyze the dynamic characteristics of the working device of the hydraulic excavator. The load changes on the two digging trajectories were calculated and analyzed by using the limit digging force model and the theoretical digging force model, respectively. The rigid-flexible coupling model of the working device was established in ADAMS. Taking the limit digging force (LDF) and the theoretical digging force (TDF) as the external load of the working device, the dynamic simulation of the hinge force of the working device in the two trajectories was carried out, and the structural strength analysis of the bucket was carried out by using ANSYS. The results show that the tangential force of the LDF is generally larger than that of the TDF, the hinge point force of the working device changes dynamically with the external load of the tooling, and the influence of the LDF on the hinge point force is greater than that of the TDF. When the LDF is taken as the external load, the structural strength of the bucket meets the operational requirements.

Train derailments in railway switches are becoming more and more common, which have caused serious casualties and economic losses. Most previous studies ignored the derailment mechanism when vehicles pass through the turnout. With this consideration, this work aims to research the 3D derailment coefficient limit and passing performance in turnouts through the quasi-static analysis and multi-body dynamic simulation. The proposed derailment criteria have considered the influence of creep force and wheelset yaw angle. Results show that there are two derailing stages in switch panel, which are climbing the switch rail and stock rail, respectively. The 3D derailment coefficient limit at the region of top width 5 mm to 20 mm is much lower than the main track rail, which shows that wheels are more likely to derail in this area. The curve radius before the switch rail is suggested to be set as 350 m. When the curve radius before turnout is 65 m, the length of the straight line between the curve and turnout needs to be larger than 3 m. This work can provide a good understanding of the derailment limit and give guidance to set safety criteria when vehicles pass through the turnout.

Zero-dimensional two-stage SOFC stacks dynamic model was developed to investigate the effect of operating parameters on stacks performance. The model resolves spatially thermal and thermo-electrochemical behaviour for electrochemical reactions, Catalytic Partial Oxidation and Steam Reforming processes. Design variables and thermo-electrochemical properties were obtained from in-house-fabricated SOFCs carried out by project partners. The completed SOFCs based Combined Heat and Power, CHP, system model was validated by data 18 and numerical results obtained at steady-state mode showing its high-fidelity. A parametric study with respect to key operating parameters including changes in fuel utilization, lambda number and current density values was conducted. The global CHP system dynamic response, in term of the current/voltage delivered by two-stage SOFC stacks, under a fixed fuel utilization, has been determined resulting in greater variations in the voltage of a single cell in the first stack in comparison to the corresponding values in the second stack.

Dynamic simulation of mechanical systems can be performed using a multibody system dynamics approach. The approach allows to account systems of other physical nature, such as hydraulic actuators. In such systems, the nonlinearity and numerical stiffness introduced by the friction model of the hydraulic cylinders can be an important aspect to consider in the modeling because it can lead to poor computational efficiency. This paper couples various friction models of a hydraulic cylinder with the equations of motion of a hydraulically actuated multibody system in a monolithic framework. To this end, two static friction models, the Bengisu–Akay model and Brown–McPhee model, and two dynamic friction models, the LuGre model and modified LuGre model, are considered in this work. A hydraulically actuated four-bar mechanism is exemplified as a case study. The four modeling approaches are compared based on the work cycle, friction force, energy balance, and numerical efficiency. It is concluded that the Brown–McPhee approach is numerically the most efficient approach and it is well able to describe usual friction characteristics in dynamic simulation of hydraulically actuated multibody systems.

Wind farm is the cheapest renewable energy resource (RER) in the world, however, the reliability improvement is a key for the future of this power plant. A specially issue is the overhead line interconnection, a weak point, even, a double circuit, the last projects have included modern equipment to mitigate the failure impact in the system as phasor measurement unit (PMU) and Intelligent Electronics Devices (IED); for the dynamic response and protection system. In this paper, a comprehensive dynamic model for the analysis in a Peruvian power plant, located in the north of Peru, with the most recent model based fault analysis and fault tolerant, focusing on overhead lines maximum disconnection time for RER technology interconnection. The remainder of this paper is organized in a tutorial manner with a Matlab code and DigSilent simulation, it allows the same results from the stability study, however faster than traditional methodology and with high accuracy.

In the present paper, an attempt has been made to introduce a new Stability Index (SI) for induction motors (IMs) three-phase fault recovery in industrial networks. The proposed SI is based on the steady-state model of induction machine as well as the usage of concepts related to stable and unstable equilibrium points. This index is evaluated by estimating the post-fault slip and is a function of the maximum slip and slips related to the induction motor operating point in pre-fault and post-fault torque-slip characteristics. Moreover, this index quantifies the amount of stability in addition to the stability state determination. The method is validated through comparison between the analytical and dynamic simulation results. Sensitivity analysis has also been used to describe the proposed index completely. This paper also presents a novel objective function by which the fault recovery process can be done optimally. The proposed method presented in this paper has also been applied to two industrial networks, one of which is the modified IEEE 9-bus system.

Extractive distillation is widely accepted and commercialized for separating azeotrope mixtures, but using traditional organic solvents leads to intrinsic obstacles such as the high energy requirement and solvent-related environmental problems. Benefiting from the development of green solvents, using ionic liquids instead of traditional solvents as entrainers for extractive distillation has attracted wide attention. This paper presents a multi-objective optimization strategy to integrate the design and control of the ionic liquid-based extractive distillation processes. In the optimization processes, the condition number (CN) and total annual cost (TAC) are minimized as the objective functions to evaluate the control properties and design of three different separation systems. The optimization results are shown by the Pareto front, which is based on trade-offs between controllability and economics. The environmental impact is evaluated by the environmental impact potential of energy for each system in a posterior stage during the optimization processes. Designs with minimum TAC (PT), trade-off designs between TAC and CN (PO) and designs with minimum CN (PC) on Pareto front are optimized and compared. The results show that the increase of reflux ratio can improve the control properties for the ionic liquid-based extractive distillation processes. Furthermore, the dynamic simulation of PT and PO are carried out to compare their dynamic responses based on the same dynamic control structure, and PO shows better performance in the aspects which include maximum deviation and residual error of dynamic response.

At present, nitrogen production from air by pressure swing adsorption (PSA) is simulated almost exclusively at low product purity levels (2). However, with increasing global demand for highly purified gases provided by energy-efficient separation processes the requirement for either extensive experimental research in the high-purity range or predictive computer simulations arises. This paper presents a mathematical model of a twin-bed PSA plant equipped with a carbon molecular sieve (Shirasagi MSC CT-350) for the generation of high-purity nitrogen (99.9–99.999% N2). The model is implemented in the process simulator Aspen Adsorption™. The influence of operating conditions as well as the cycle organisation on the process performance is validated, especially the influence of pressure, temperature, half-cycle time, purge flow rate, and cutting time. The precision of the performance prediction by numerical simulations is critically discussed. Based on the new insights efficiency improvement strategies with a focus on reduced energy consumption are introduced and discussed by means of radar charts.

In this research, frequency and resonance area information of a size-dependent electro-elastic rotary non-classical piezoelectric microdisk via modified couple stress theory (MCST) is presented. Th...

The meniscus, composed of fibrocartilage, is a very important part of the human knee joint that behaves like a buffer. Located in the middle of the femoral condyles and the tibial plateau, it is a necessary structure to maintain normal biomechanical properties of the knee. Whether walking or exercising, the meniscus plays a vital role to protect the articular surface of both the femoral condyles and the tibial plateau by absorbing the conveying shock from body weight. However, modern people often suffer from irreversible degeneration of joint tissue due to exercise-induced harm or aging. Therefore, understanding its dynamic characteristics will help to learn more about the actual state of motion and to avoid unnecessary injury. This study uses reverse engineering equipment, a 3D optical scanner, and a plastic teaching human body model to build the geometry of knee joint meniscus. Then, the finite element method (FEM) is employed to obtain the dynamic characteristics of the meniscus. The results show the natural frequencies, mode shapes, and fatigue life analysis of meniscus, with real human material parameters. The achieved results can be applied to do subsequent knee dynamic simulation analysis, to reduce the knee joint and lower external impacts, and to manufacture artificial meniscus through tissue engineering.

The objective of this study was to simulate a proton-electrolyte membrane fuel cell (PEMFC) system, namely a PEMFC stack, an anode gas supply subsystem, an anode gas-recovery subsystem, a cathode gas supply subsystem, and a tail gas exhaustion subsystem. In addition, this paper presents an analysis of the efficiency of combined heat and power (CHP) systems. MATLAB and Simulink were employed for dynamic simulation and statistical analysis. The rates of active and the passive anode hydrogen recirculation were considered to elucidate the mechanism of hydrogen circulation. When recovery involved diverse recovery mechanisms, the recirculation rate was affected by the pressure at the hydrogen outlet of the PEMFC system. The greater the pressure was at that outlet, the higher the recovery rate was. In the hydrogen recovery system, when the temperature of the hydrogen supply end remained the same, increasing the temperature of the gas supply end increased the efficiency of the fuel cells; fixing the flow of the hydrogen supply end and increasing the temperature of the hydrogen supply end increased the efficiency of the PEMFC system. A calculation of the efficiency of the recovery system indicated that the thermal efficiency of the fuel cells exceeded 35%, the power generation efficiency exceeded 45%, and the efficiency of the CHP system exceeded 80%.

This letter proposes an analytical expression on transient overvoltage peak value caused by DC blocking (DCB) and commutation failure (CF). The proposed method can obtain the transient overvoltage risk without modeling the complex AC/DC hybrid system. The method only requires the equivalent parameters of the AC system and the operation parameters of the DC system to effectively calculate the overvoltage without using the dynamic simulation software. The simulation results verify the effectiveness and correctness of the proposed method.

Introduction. Simulation of the 2D dynamic motion of a high altitude wide span gantry crane with a rope hoisting mechanism is addressed. Such large gantry cranes with a height of more than 50 meters, have been unstudied very well so far. A small swing angle of the payload, it's fast hoisting, and the fast motion of the trolley are critical for these cranes and, hence, they need to be analyzed in detail. Materials and methods. The generalized formulation of the two-dimensional crane dynamics is efficiently performed and simulated in Mathcad. This is a single mass model that has a non-elastic cable. The formulation is derived using the Lagrange method, and differential equations are correctly solved using the Runge-Kutta method in Mathcad. In this model the crane is fixed, and all the subsystems are considered as rigid bodies without any deflection in terms of the trolley and the payload. Results. The results are verified using MSC ADAMS (Academic) that indicates satisfactory convergence. The considerable influence of the payload oscillation on the trolley motion is visible in both Mathcad and ADAMS models. The implemented Mathcad code can be useful for students and researchers. Conclusions. The maximum speed of the trolley is 1.716 m/s to prevent the payload swinging angle from exceeding 0.5 deg. The calculated velocity of the trolley is reasonable for such a large crane if limitations like wind effects and resonance are ignored.

Autonomous on-orbit servicing, such as capture, refuel, repair and refurbishment of on-orbit satellites using a robotic arm mounted on servicing satellite is one of the important components of future’s space missions. Space robots increase reliability, safety, and ease of execution of space operations, but pose a novel challenge due to micro-gravity and space environments. While capturing high speed orbiting objects, robotic arms undergo impact and require appropriate modeling of the system. In this paper, a unified framework is provided for modeling impact dynamics, post-capture stabilization and target maneuvering of a multi-arm robotic system mounted on a servicing satellite while capturing orbiting objects. The dynamic model of multi-arm space robot is obtained using the Decoupled Natural Orthogonal Complement (DeNOC) based formulation and closed-loop constraint equations. All three phases of the capturing operation, namely, approach, impact, and post-impact are modeled using Impulse-momentum approach and conservation of momentum. In the approach phase, robot arms are planned to move from its initial configuration to the desired capture configuration. In the impact phase, a framework is developed to estimate the impulse forces and changes in the generalized velocities caused by the impact. In post-impact phase, these velocities are used as initial conditions for the post-impact dynamics simulations. The uncontrolled dynamics during post-impact will result in an undesirable motion, thus post-impact reactionless control (minimum base disturbance) strategy is used to maneuver the space robot’s arms and target object. As such, the robotic arms can be used to maneuver an astronaut for repair of satellite. Most of the times the parameters of target object are not known. Hence, an adaptive reactionless control strategy has been devised for capturing object with unknown parameters. The effectiveness of the framework is shown using a dual-arm robot mounted on a servicing satellite performing capturing operation for multiple objects. The effects of relative velocity and angle of approach on the impact forces are also investigated.

The growth of pipeline inspection robots has been increasing in power plants, oil, gas, and sewage system industries, etc. To cater to this need, the main focus of this paper is to design and develop a pipeline inspection robot (PIR) for underground pipelines. In this paper, a novel design concept of PIR is proposed which uses a scissor mechanism consisting of two cross-links and a lead screw for self-adjusting and controlling of the robot during motion. The motion of the scissor mechanism is controlled by a DC motor. The mathematical model for understanding the kinematics and dynamics of the scissor mechanism has been developed. Further, kinematic and dynamic simulation has been carried out with help of ADAMS software. The experimental results have proved that the scissor mechanism can be useful for self-adjusting the operation of the robot during intervention with variable cross-sectional diameters of pipelines. A prototype of PIR is developed for testing the mechanism. Experiments have been conducted for the inspection of pipelines. An image processing technique is applied for finding the cracks inside the steel pipelines. Therefore, we can say, based on the results obtained, that the developed robot can solve the problems of inspection of the underground pipelines. This robot can also reduce human participation in labor-intensive/ dangerous work. It can also work in inaccessible areas during the repair and maintenance of the underground pipelines in various industries.

Purpose This paper aims to develope a novel fractional hybrid impedance control (FHIC) approach for high-sensitive contact stress force tracking control of the series elastic muscle-tendon actuator (SEM-TA) in uncertain environments. Design/methodology/approach In three different cases, the fractional parameters of the FHIC were optimized with the particle swarm optimization algorithm. Its adaptability to the pressure of the sole of the foot on real environments such as grass (soft), carpet (medium) and solid floors (hard) is far superior to traditional impedance control. The main aim of this paper is to derive the dynamic simulation models of the SEM-TA, to develop a control architecture allowing for high-sensitive contact stress force control in three cases and to verify the simulation models and the proposed controller with experimental results. The performance of the optimized controllers was evaluated according to these parameters, namely, maximum overshoot, steady-state error, settling time and root mean squared errors of the positions. Moreover, the frequency robustness analysis of the controllers was made in three cases. Findings Different simulations and experimental results were conducted to verify the control performance of the controllers. According to the comparative results of the performance, the responses of the proposed controller in simulation and experimental works are very similar. Originality/value Origin approach and origin experiment.

This article presents a dynamic simulation study for the modeling and identification of a 5 kW Proton Exchange Membrane (PEM) fuel cell system using intelligent ANN approach to get rid of the complexity involved in the analytical modeling as it is intricate with the highly non-linear dynamics such as electrochemical, thermodynamic and water-transport mechanisms. The proposed artificial networks for the prediction and identification of a highly non-linear fuel cell system performance are Radial Basis Function Network (RBFN), dynamic Elman Recurrent Network (ERN) and NARX Recurrent Network (NRN) that has delayed context unit. A comparative study is made between the performances of the proposed neural network models for identifying an optimal network structure and configuration based on network performance measures. The optimal NARX network ascertained having an appreciable learning and generalization ability is adopted for the prediction and identification of the fuel cell system for its static and dynamic behavior. The network prediction over the system behavior shows good agreement with the benchmark results acquired from a 5 kW-Ballard fuel cell system. The proposed optimal intelligent parametric model can facilitate in replacing a highly non-linear fuel cell system in the fuel cell related model developments that are adopted in several research sectors particularly in transportation applications.

As a process intensification technology, semicontinuous distillation uses less equipment to achieve the separation of multiple components. However, there is still a lack of systematic guidance for the design of semicontinuous distillation. In this paper, we propose a new method to guide the design of semicontinuous distillation via multi-objective optimization (MOO) and control. Conventional continuous distillation, dividing wall column (DWC) distillation and semicontinuous distillation for separation of n-alkanes are optimized through multi-objective genetic algorithm (MOGA). Several different control schemes are proposed for semicontinuous distillation, and the temperature-concentration cascade control scheme CS5 is selected as the optimal control scheme. The economic benefits of semicontinuous distillation based on dynamic simulation are evaluated by the comparison with the conventional continuous distillation and DWC under a series of throughput. It is found that the total annual cost (TAC) of the semicontinuous distillation is smaller than that of conventional continuous distillation when the annual throughput is less than 7.73 × 104 kmol/yr. And the TAC of the semicontinuous distillation is less than that of DWC when the annual throughput is less than 5.29 × 104 kmol/yr. Therefore, we can conclude that the semicontinuous distillation has better economic benefits than the other two configurations within the smaller annual throughput.

Population balance model is crucial for improving the method of aluminum hydroxide massive crystallization and enhancing the quality of control over industrial precipitation trains. This paper presents the updated population balance model, which can be used for simulation of industrial-scale precipitation. Processes of birth-and-spread and particle breakage are considered integral parts of the precipitation process along with secondary nucleation, growth and agglomeration of particles. The conceptual difference of the proposed system of equations is its ability to reproduce the oscillatory process that occurs in precipitation circuits as a result of cyclic changes in the quality of the seed surface. It is demonstrated that self-oscillations can occur in the system without any external influence. The updated model is adjusted and verified using historical industrial data. The simulation of seed-recycle precipitation circuit showed an exact correspondence between the calculated dynamic pattern of changes in particle size distribution of aluminum hydroxide and the actual data.

This work presents a dynamic model of the reactive side of large-scale fluidized bed (FB) boilers that describes the in-furnace transient operation of both bubbling and circulating FB boilers (BFB and CFB, respectively). The model solves the dynamic mass and energy balances accounting for the bulk solids, several gas species, and the fuel phase. The model uses semi-empirical expressions to describe the fluid dynamics, fuel conversion, and heat transfer to the furnace walls, as derived from units other than the studied ones. The model is validated against operational data from two different industrial units: an 80 MW CFB and a 130 MW BFB, both at steady-state and transient conditions. The validated model is used to analyze: (i) the performance of the reactive side of two FB boilers under off-design, steady-state conditions of operation; and (ii) the open-loop transient response when varying load or fuel moisture. The results underline the key role of heat capacity on the stabilization time. Within a given unit, the differences in heat capacity between the top and bottom of the furnace affect also the stabilization times, with the furnace top (lower heat capacity) being 1–3 times faster in the CFB unit and up to 10 times faster in the BFB unit. Due to the differences in gas velocity, the investigated boilers are found to stabilize more rapidly to input changes when running at full load than at partial load. Lastly, a variable ramping rate analysis shows that the inherent transient responses of the reactive side disappear when disturbances are introduced at (slower) rates, typical of industrial operation. Thus, the reactive side could be modeled as pseudo-static.

Desublimation-based Carbon dioxide (CO2) removal from the natural gas (NG) in a cryogenic packed bed becomes challenging due to the dry ice formation inside the packed bed. Therefore, the cryogenic packed bed has been used for NG purification only in batch processes. However, to fulfill the energy requirements, it is crucial to develop a continuous process for NG purification, which is difficult for a single cryogenic packed bed. In the current research, a novel cryogenic packed bed system is proposed for continuous capture of desublimation based CO2 capture from natural gas. The process feasibility of the switching concept was proved through dynamic simulation and experimental study on CO2 separation from multi-component NG. It was observed that increasing CO2 content decreases the switching and saturation time of the cryogenic packed bed. The total energy required per packed bed per cycle in the switching system is 133.35. The saturation time for pure CO2 feed, NG sample-1, and NG sample-2 were 300, 500, and 600 s, respectively. An excellent agreement was observed between the results obtained from the experimental results and that obtained through dynamic simulation. A switching time of 200 s was found for a CO2 recovery of more than 98 %. This research work offers scientific data and theoretical support for the industrial application of switched cryogenic packed bed setup in CO2 capture from natural gas in the future. Moreover, in the current research work, scale-up study, and automatic control system for the switched packed bed are recommended for the future.

Conventionally, researchers conducted field tests and modeling works for the Variable Refrigerant Flow system separately. In this study, we used the compressor model as a case study to illustrate a novel approach to integrate field tests and modeling works. Field tests in an office building were conducted to collect data. For mass flow rate prediction, three traditional models, including the 20-coefficient model, the efficiency-based model, and the efficiency-based 20-coefficient model, and three machine-learning-based models including Support Vector Regression, Neural Network, and Random Forest, were investigated and compared. We found that the efficiency-based 20-coefficient model and the Support Vector Regression model had a higher accuracy (the mean relative errors were 0.11% and 0.15%, and the coefficient of variation of the root mean-square-error were 0.20 and 0.23) and lower uncertainty within 0.2 g•s−1 for steady-state operation prediction. However, all six models failed to predict accurately the beginning part of the transient process. A tens-of-seconds delay existed between the predicted values and the experiment values. We applied the Convolutional-Neural-Network-based model to address this problem. The mean relative error of this model is reduced to 2% for dynamic simulation. In summary, we recommend the efficiency-based 20-coefficient model, and the Support Vector Regression model for the steady-state compressor model development, while the Convolutional-Neural-Network-based model is recommended for transient model development. For the power consumption prediction, 20-coefficient and Neural Network models can predict transient data well. The process of predicting the capacity is the same as the process of mass flow rate prediction.

Existing generator parameterization methods, typically developed for large turbine generator units, are difficult to apply to small kW-level diesel generators in microgrid applications. This paper presents a model parameterization method that estimates a complete set of kW-level diesel generator parameters simultaneously using only load-step-change tests with limited measurement points. This method provides a more cost-efficient and robust approach to achieve high-fidelity modeling of diesel generators for microgrid dynamic simulation. A two-stage hybrid box-constrained Levenberg-Marquardt (H-BCLM) algorithm is developed to search the optimal parameter set given the parameter bounds. A heuristic algorithm, namely Generalized Opposition-based Learning Genetic Algorithm (GOL-GA), is applied to identify proper initial estimates at the first stage, followed by a modified Levenberg-Marquardt algorithm designed to fine tune the solution based on the first-stage result. The proposed method is validated against dynamic simulation of a diesel generator model and field measurements from a 16kW diesel generator unit., Comment: 9 pages, 9 figures, accepted by IEEE Transactions on Smart Grids

Long-span bridges suspended from floating towers are a promising design concept to cross the strait with deep water depth. This paper presents an alternative dynamic simulation framework for floati...

Due to the cold and dry climate during the winter season of Central Asia, in order to prevent frostbite and vines drying out for wine grapes, the common methods are burying the vines in winter under a thick layer of soil and then cleaning them out in the next spring. The design of existing vine digging machinery is not precise enough and can only remove the outer layer of the soil on both sides and the top. It cannot clean the soil from the central area of the buried vine. Sometimes, the branches and buds get damaged due to uneven driving condition. To solve the problem, an innovative non-contact blower was designed and tested to clean the vine. In this paper, the design specifications and operation parameters of the blower were determined according to the agronomic properties of the grapevines. Fluent-EDEM coupling, that is, with the help of Engineering discrete element method (EDEM) and CFD fluid simulation software Fluent, was the most common method for dynamic simulation of gas-solid two-phase flow. The Fluent-EDEM coupling simulation was used to simulate the dynamics of soil particles under the action of different wind speeds and blowing patterns, with the goal of a high soil cleaning rate. A prototype of the soil cleaning blower was manufactured and tested at the vineyards of Ningxia Yuquanying Farm in China. The results showed that the blower had an operation efficiency of 4669 m2·h−1, with an average soil removal rate of 80%. The efficiency of covering soil cleaning and rattan raising was greatly improved, and the damage rate of the vines, branches and the buds was greatly reduced.

The actuator is an important component of missiles and other aircraft to maintain the flight attitude. A method to calculate the power of the electric servo motor was proposed according to the load characteristics’ of both the servo motor and actuator. An optimization method for the transmission reduction ratio was obtained by considering the load torque equation. Dynamics simulations of the actuator were conducted under a variety of conditions. The simulation results show that the clearance and the friction between the ball screw and the fork, which consist of the transmission mechanism, induce the torque fluctuations, as a source of noise in the motor load. According to the optimization design of the Electric, the Actuator prototype has passed the test, the performance meets the design requirements.

There are some difficult problems in deep and ultra-deep oil and natural gas drilling process due to the complex stress environment and hard formation, such as slow drilling speed, well deviation and high cost. As one of the important parameters to measure rock-breaking efficiency, mathematical model of failure volume is proposed in this paper, which is suitable for deep-well rock-breaking technology. First, the particle jet impact rock-breaking laboratory experiment was conducted based on the self-developed experimental platform, and the strength of rock specimen was tested. Then, the failure volume model of particle jet impact rock-breaking which varied with particle size, and water-jet velocity was established based on contact mechanics. Meanwhile, the simulation model and method of particle jet impact rock was carried out and introduced, and damage evolution was dynamical simulated. Comparative analysis of experiment results, model calculation and dynamic simulation was used to analyze the failure volume, and it showed, failure volume would increase linearly with increase of water-jet velocity, while particle size has little effect on failure volume under the condition of constant nozzle diameter. The comparison results of theoretical modeling and rock-breaking experiment are basically consistent, which proves the correctness and applicability of failure volume model.

Objective: Musculoskeletal models play an important role in surgical planning and clinical assessment of gait and movement. Faster and more accurate simulation of muscle paths in such models can result in better predictions of forces and facilitate real-time clinical applications, such as rehabilitation with real-time feedback. We propose a novel and efficient method for computing wrapping paths across arbitrary surfaces, such as those defined by bone geometry. Methods: A muscle path is modeled as a massless, frictionless elastic strand that uses artificial forces, applied independently of the dynamic simulation, to wrap tightly around intervening obstacles. Contact with arbitrary surfaces is computed quickly using a distance grid, which is interpolated quadratically to provide smoother results. Results: Evaluation of the method demonstrates good accuracy, with mean relative errors of 0.002 or better when compared against simple cases with exact solutions. The method is also fast, with strand update times of around 0.5 msec for a variety of bone shaped obstacles. Conclusion: Our method has been implemented in the open source simulation system ArtiSynth ( www.artisynth.org ) and helps solve the problem of muscle wrapping around bones and other structures. Significance: Muscle wrapping on arbitrary surfaces opens up new possibilities for patient-specific musculoskeletal models where muscle paths can directly conform to shapes extracted from medical image data.

For the long-term dynamic simulation of a fluidized bed reactor (FBR), a two-way coupled computational fluid dynamics (CFD)-direct quadrature method of moments (DQMOM) approach is proposed. In this approach, CFD is first used only for hydrodynamic information without simulating any other chemical reactions or physical phenomena. Subsequently, the derived information is applied to the DQMOM calculation in MATLAB. From the calculation, a particle size distribution is obtained and subsequently adopted in a new CFD model to reflect the flow change caused by a change in the particle size distribution. Through several iterative calculations, long-term dynamic simulations are performed. To evaluate the efficacy of the proposed approach, the results from the suggested approach are compared for 60 s with those of the CFD-quadrature method of moments (QMOM) approach, which calculates hydrodynamics and physical phenomena simultaneously in CFD. The proposed approach successfully simulated the FBR for 6 h. The results confirmed that the proposed method can simulate complex flow patterns, which cannot be obtained in conventional CFD models. Another advantage of the approach is that it can be applied to various industrial multiphase reactors without any tuning parameters.