Journal of Applied Dynamic Systems and ControlJournal of Applied Dynamic Systems and Control
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Feed provided by Journal of Applied Dynamic Systems and Control. Click to visit.Numerical Study of the Effect of Temperature Changes on the Failure Behavior of Sandwich ...
http://jadsc.aliabadiau.ac.ir/article_671183_1133479.html
In this paper, failure modes of sandwich panels are investigated numerically using finite element method. For this purpose, four sandwich beams of GFRP laminate skins and Nomex honeycomb core are considered. The models have been chosen so that they could cover all failure modes according to available experimental failure mode maps. Models are created and analyzed based on standard 3-points bending test, using ASTM standard C393-62. In order to investigate the effect of loading and sandwich panel parameters on failure behavior, finite element analysis has been utilized. The results are verified by comparing experimental and theoretical results. The constructed failure mode map shows dependence of failure mode on the ratio of skin thickness to span length, and honeycomb relative density. To Then, effect of temperature on the failure modes of sandwich panels, has been investigated. Results show that failure modes haven’t depended on environment temperature and failure load decreases by increasing environmental temperature. The slope of reduction is a function of beam geometrical parameters. Depending on the parameters, the failure loads decrease between 10% to 40% by increasing environmental temperature.Sat, 30 Nov 2019 20:30:00 +0100Numerical study of the effect of temperature changes on the failure behavior of sandwich panels ...
http://jadsc.aliabadiau.ac.ir/article_671186_0.html
In this paper, failure modes of sandwich panels are investigated numerically using finite element method. For this purpose, four sandwich beams of GFRP laminate skins and Nomex honeycomb core are considered. The models have been chosen so that they could cover all failure modes according to available experimental failure mode maps. Models are created and analyzed based on standard 3-points bending test, using ASTM standard C393-62. In order to investigate the effect of loading and sandwich panel parameters on failure behavior, finite element analysis has been utilized. The results are verified by comparing experimental and theoretical results. The constructed failure mode map shows dependence of failure mode on the ratio of skin thickness to span length, and honeycomb relative density. To Then, effect of temperature on the failure modes of sandwich panels, has been investigated. Results show that failure mods haven’t depended on environment temperature and failure load decreases by increasing environmental temperature. The slope of reduction is a function of beam geometrical parameters. Depending on the parameters, the failure loads decrease between 10% to 40% by increasing environmental temperature.Sat, 08 Feb 2020 20:30:00 +0100Comparison between the Distributed Entropy Method and Average Cost Theory Method in ...
http://jadsc.aliabadiau.ac.ir/article_671192_1133479.html
Residues are disposal remaining flows of matter or energy that are produced by energy systems. Residues cost allocation is a complex problem. One of the most important criteria for residues cost allocation is distributed entropy method. In this method, the fuel-product (FP) table (a mathematical representation of the thermoeconomic model) is used as input data. Average cost theory (ACT) method is one of the most important conventional exergoeconomic methods that can be applied to energy systems. In this paper, distributed entropy method and ACT method are applied to a combined cycle and a cogeneration system. Fuel and product costs for each component are obtained and compared with each other. Specific cost of product for each component is calculated, too.Sat, 30 Nov 2019 20:30:00 +0100Investigation of Distance Relay Performance in Presence of Resistive Bridge-Type Fault ...
http://jadsc.aliabadiau.ac.ir/article_671196_1133479.html
Due to the development of fault current limiters (FCLs) for employment in high voltage (HV) level power system, the possibility of utilizing them in transmission systems has increased. Installation FCLs have significantly advantages to flexible and reliable operation of power system. Despite the more advantages of installation FCLs, it affects on the transmission lines protection system, which is commonly protected with distance relays.FCLs change the impedance of transmission lines during fault, which can lead to failure operation of distance relay. In this work, the effect of resistive bridge-type fault current limiter (RBFCL) on the apparent impedance seen by distance relay is investigated. For achieve this, first, the RBFCL is modeled in PSCAD/EMTDC and then the effect of its impact on the distance relay characteristic is evaluated. To this study different short circuit fault including single line to ground (SLG) and line to line (LL) faults are taken in to account. Simulation results reveal the adverse impact of the RBFCL on distance relay performance.Sat, 30 Nov 2019 20:30:00 +0100Analysis of Coordination between Surge Protection Devices in Low Voltage Electric Networks
http://jadsc.aliabadiau.ac.ir/article_671212_1133479.html
Low voltage Surge Protection devices (SPDs) are one of the most important electrical equipments to protect the electric networks against transient destructive electrical waves. Using only one SPD, in general, is not enough due to either large distances between SPDs and electric loads or high sensitivity of the electric networks’ apparatuses. In practice, to make conditions better, several SPDs are used simultaneously and in due order. In this case, right technical selection of each of the SPDs and the electrical distance between each pair play an important role to achieve an effective protection system to keep the electrical equipments safe; this is specifically important since having not taken into account the SPDs specifications and the distance between each pair would lead into destructions of electric equipments and even SPDs themselves. In this paper, though modeling and simulation of a complete low voltage network, coordination's between a two-stage protection systems will be analyzed; modeling and studies have been implemented in EMTP-RV software package and results extracted and investigated. The outcomes of this study have pointed out that when SPDs are selected technically rightfully, an increase in the cable between two SPDs would increase the absorbed energy and current discharge in the upstream SPD and decrease the voltage of the SPD near to the load.Sat, 30 Nov 2019 20:30:00 +0100SEPIC Converter Based Maximum Power Point Tracking of a Photovoltaic System Using ...
http://jadsc.aliabadiau.ac.ir/article_671255_1133479.html
In this paper, an intelligent control system using state-space feedback controller designed to track the maximum power radiation direction of the sun for a photovoltaic system in a varying direction environment will be studied. In fact, the study focuses on the ability of using the state space feedback controller to control the power oscillation around the optimal point such that the power dissipation is minimized. Furthermore, the control system based on the instantaneous power tracking and with respect to the nonlinear photovoltaic cell makes feasible to access the maximum possible electric power using tiny changes in the Single Ended Primary Inductor Converter (SEPIC).Sat, 30 Nov 2019 20:30:00 +0100Improvement of Quality Specifications of Light-Emitting Diodes based on the Photonic Crystals
http://jadsc.aliabadiau.ac.ir/article_671314_1133479.html
In this paper, a new structure of Light-Emitting Diodes (LEDs) based on the usage of Gallium Nitride (GaN) semiconductors has been proposed in which, in order to improve the efficiency of the output light, a reflective layer along with two Photonic Crystal (PC) layers have been employed. The applied changes and their optimization illustrated increase in output light efficiency as much as 133% with respect to a typical LED.Sat, 30 Nov 2019 20:30:00 +0100Compensation of Current Harmonic Components of Nonlinear Loads in Presence of Distributed ...
http://jadsc.aliabadiau.ac.ir/article_671358_1133479.html
Filtering the harmonics produced by nonlinear loads in power systems is an important issue for the engineers to follow. In most cases, to this end, active filters have been used. In this paper, however, it is shown that this task can be accomplished using a Multi-Criteria algorithm and distributed generations (DGs) resources. In the proposed algorithm, when the DGs are connected to the main network, compensations of active and reactive powers as well as harmonic components are possible. To do so, first, the dynamical model of the systems will be shown in details in the static three-phase system, and then, they are transferred to a rotating orthogonal set using the necessary conversion equations. Therefore, the transferred variables are used to control the voltage source converters in order to achieve improvements in DGs’ behavior when they are connected to the network. In this control method, the active and reactive powers transmitted to the load as well as the current harmonics are compensated using samples of voltages and currents taken at the connection points; thus capabilities for sinusoidal current and maximum active power transmissions are provided. Besides, the control proposed method has a fast dynamical response in active and reactive power compensations. Therefore, using this control approach, the transmitted power of DGs to the network are maximized, the power coefficient factor is improved and current harmonics of the load are decreased significantly.Sat, 30 Nov 2019 20:30:00 +0100