Research Article
Flight mechanics/Navigation/Control/...
Mohammad Hosein Alizadeh; Alireza Toloei
Articles in Press, Accepted Manuscript, Available Online from 15 April 2023
Abstract
The intended aircraft in this issue is an UAV type, capable of performing multiple missions. In this paper, after the linearization of the pitch channel, the transfer function for important points is extracted. After that, a robust classic compensator and an angular velocity damper are designed. According ...
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The intended aircraft in this issue is an UAV type, capable of performing multiple missions. In this paper, after the linearization of the pitch channel, the transfer function for important points is extracted. After that, a robust classic compensator and an angular velocity damper are designed. According to the range of uncertainties, the compensator is adjusted by article bee colony algorithm. Also, the optimal value of the wing sweep back angle is obtained indirectly from the optimal value of the center of aerodynamic pressure. The optimization approach in this pepper is to make pitch channel robust to uncertainties. The results show that with the innovation in the design of the classic controller and its combination with Mont Carlo simulation and Optimization algorithm, the behavior of the pitch channel in the presence of uncertainties has been improved.
Research Article
Maintenance of Engine, Wings and Fuselage of Aircraft/Technology/Manufacturing/...
Saeed Ramezani; Hamzeh Soltanali; Amir Beirami
Articles in Press, Accepted Manuscript, Available Online from 05 August 2023
Abstract
One of the main propositions of predictive maintenance is Prognostics and Health Management (PHM) which plays a unique role in identifying, diagnosing, and predicting the health status of physical assets. To that end, one of the fundamental solutions is to assess the condition of the equipment in the ...
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One of the main propositions of predictive maintenance is Prognostics and Health Management (PHM) which plays a unique role in identifying, diagnosing, and predicting the health status of physical assets. To that end, one of the fundamental solutions is to assess the condition of the equipment in the aviation sector in order to provide maintenance plans by determining the trend of deterioration or destruction. In this study, a developed model of an artificial neural network was presented, focusing on the concept of deep learning and its comparison with other conventional methods, in response to the limitations and uncertainties in traditional prediction methods in determining the deterioration process of the equipment. The comparative results revealed that the deep learning neural network method with a prediction accuracy of 94% had a high performance in determining the deterioration process in aircraft turbine engines compared to other conventional methods. The findings of this study can be used to predict the remaining useful life of aviation industry equipment and to provide appropriate maintenance programs.
Research Article
Propulsion/Thermodynamics/Heat Transfer/Fuel and Combustion/Energy/...
MohamadAmin Borghei; Muhammad Amin Eskandari
Articles in Press, Accepted Manuscript, Available Online from 07 September 2023
Abstract
In general, according to the Russian Gost standard, the space propulsion engine system includes injection subsystems, thrust chamber, heat transfer and cooling system, launch system, feeding system, thrust vector control system which due to overlap and penetration The manifolds between the engine reservoirs ...
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In general, according to the Russian Gost standard, the space propulsion engine system includes injection subsystems, thrust chamber, heat transfer and cooling system, launch system, feeding system, thrust vector control system which due to overlap and penetration The manifolds between the engine reservoirs and the fuel system are usually designed as a pair. In the conducted investigations, in addition to knowing the elements of the circuit and how to arrange the circuit, it also leads to knowing the requirements, goals and main requirements of the system design. Then, based on the studies, the circuit design of the feeding system and the selection of its elements have been done.Considering the cryogenic of the propellants in this project, design considerations for routes and tanks will be more important, and finally, sensitivityanalysis and conceptualdesign considerations have been presented.In this article, the types of feeding systems, Ahead problems and challenges are discussed and finally model of this subsystem will be presented based on the TRL
Research Article
Space Engineering/Space Orbit Mechanics/Space Sciences/...
Narges Talebi Motlagh; Sevil Mohammadzadeh Sadigh; hossein beheshti; hamid Ghouchi Eskandar; Moharram Shameli
Articles in Press, Accepted Manuscript, Available Online from 07 October 2023
Abstract
In this paper, passive adaptive modified sliding-mode-based fault tolerant control is designed to track the desired attitude of a satellite with four reaction wheels in the presence of external disturbances, system uncertainties, and actuator fault. In order to achieve this goal, the adaptive modified ...
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In this paper, passive adaptive modified sliding-mode-based fault tolerant control is designed to track the desired attitude of a satellite with four reaction wheels in the presence of external disturbances, system uncertainties, and actuator fault. In order to achieve this goal, the adaptive modified fast terminal SMC has been used, due to its robustness against the unmodeled uncertainties and the design of control method for the nonlinear model of system. To improve the performance of the controller, the sliding surface is selected in a way that the tracking error converges in a finite time to a small neighborhood of the origin, which is proved using the extended Lyapunov law, and avoids the singularity of the control law. The adverse effects caused by the uncertainties are reduced using an adaptive parameter in the reaching phase of the control law. This reduces the tracking error and as a result, the performance of the closed loop system is improved. Also, the adaptive parameter and sliding surface are applied as a coefficient of the reaching phase to eliminate the chattering phenomenon. The simulation results indicate the high precision attitude tracking, chattering-free, and the improved performance of closed-loop system.
Scientific extension
Aerodynamics/Fluid Mechanics/Aeroacoustics/...
mohamad hossein moghimi esfandabadi; Mohammad Hassan Djavareshkian
Articles in Press, Accepted Manuscript, Available Online from 30 October 2023
Abstract
An unmanned aircraft (UAV) is a type of aircraft that operates without the need for a human passenger. These planes are able to fly automatically, without the need for remote control, and are mostly controlled by computers and sensors. UAVs are used in many industries and have various applications, including ...
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An unmanned aircraft (UAV) is a type of aircraft that operates without the need for a human passenger. These planes are able to fly automatically, without the need for remote control, and are mostly controlled by computers and sensors. UAVs are used in many industries and have various applications, including communications, surveillance, aerial photography and videography, security and border surveillance, search and rescue, scientific and environmental studies, agriculture, as well as the military industry. The advantages of using UAVs include high efficiency, access to difficult and dangerous areas, and cost reduction. However, the use of UAVs also comes with challenges and problems. One of the most important problems is the risk of losing control, aerodynamic problems, and running out of fuel at different angles of attack. Improving aerodynamic coefficients can help increase flight safety and reduce risks related to losing control of the aircraft. In this research, we examine the elements, changing the shapes created on the airplane wing, and applying control surfaces to improve the aerodynamic coefficients.
Research Article
Propulsion/Thermodynamics/Heat Transfer/Fuel and Combustion/Energy/...
Ali Hajizadeh; Mir Yoseph Hashemi; Ali ziaie Asl
Articles in Press, Accepted Manuscript, Available Online from 30 October 2023
Abstract
Due to the very high importance of gas turbine in electricity production and also its increasing development in the electricity industry, one of the most important methods to increase the efficiency of gas turbine blades is to add thermal barrier coating to their outer surface. These coatings improve ...
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Due to the very high importance of gas turbine in electricity production and also its increasing development in the electricity industry, one of the most important methods to increase the efficiency of gas turbine blades is to add thermal barrier coating to their outer surface. These coatings improve the cooling of gas turbine blades, but they also have disadvantages such as roughness of their surface cause to the separation of the hot fluid flow around the turbine blades. The rough surfaces of thermal barrier coatings should be used optimally and purposefully. In this research, using commercial software of Fluent, this type of coating has been investigated and analyzed in order to find the most optimal possible mode for its use. The influence of surface parameters such as roughness, thickness and material of thermal barrier coatings have been investigated. The most optimal state for the mentioned parameters are: 0.1 mm, 0.38 mm and 2.7 W/m.K respectively.
Research Article
Space Engineering/Space Orbit Mechanics/Space Sciences/...
elham hosseini; razieh Narimani
Articles in Press, Accepted Manuscript, Available Online from 05 November 2023
Abstract
One of the satellite telecommunication services is the S&F service. In this article, we analyze the service characteristics and explain the impact of them on the design parameters. One of the challenges of telecommunication payload design is the mapping of service parameters to the technical requirements ...
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One of the satellite telecommunication services is the S&F service. In this article, we analyze the service characteristics and explain the impact of them on the design parameters. One of the challenges of telecommunication payload design is the mapping of service parameters to the technical requirements of payload components. First, analytical relationships between service parameters( the number of users, traffic and delay) and technical requirements( network capacity and on-board memory) are presented. Then the protocol stack and their parameters are selected with the aim of optimizing the power and network efficiency considering the link conditions. By identifying the service specifications impact on the design parameters and the design process systematic, payload requirements in order to develop network is easily extracted. One of the effective factors in the payload block diagram design is its reliability. The design of redundancy is proposed by considering the components reliability and the its function with the aim of achieving reliability and reducing fault propagation.
Research Article
Aerodynamics/Fluid Mechanics/Aeroacoustics/...
Mohammad hossein Moghimi Esfandabadi; Mohammad Hassan Djavareshkian
Articles in Press, Accepted Manuscript, Available Online from 06 August 2023
Abstract
This research investigates the effect of fence on wingtip vortices and control surfaces in a bird-like aircraft using numerical methods. In designing and placing the fence, average dimensions extracted from wing root vortices at different angles of attack have been used. In addition, the fence with specified ...
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This research investigates the effect of fence on wingtip vortices and control surfaces in a bird-like aircraft using numerical methods. In designing and placing the fence, average dimensions extracted from wing root vortices at different angles of attack have been used. In addition, the fence with specified dimensions have been installed at three heights and three different positions along the wing (the length of the winglet is equal to the average length of the vortex in that part, and the height of the winglet is 30% of the diameter of the vortex in that part) and have been examined at angles of attack ranging from 7 to 16 degrees. The next stage of the study is the optimal design of the dimensions of the control surfaces using a single objective optimization method. The aim of this research is to achieve the best possible design that converges to an optimal solution with minimum time and cost. The design of control surfaces is carried out at three points based on the dimensions of the wing root vortex using numerical methods. However, Computational Fluid Dynamics (CFD) analysis requires a lot of computational time.
Research Article
Aerodynamics/Fluid Mechanics/Aeroacoustics/...
Ramin Zakeri
Articles in Press, Accepted Manuscript, Available Online from 06 May 2023
Abstract
In this article, the deformable structures of a symmetrical airfoil and the discussion of aerodynamic forces are discussed inside the wind tunnel with miniature dimensions. The problem, which is checked in this article, is the investigation the effect of surface deformation in a small airfoil. In order ...
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In this article, the deformable structures of a symmetrical airfoil and the discussion of aerodynamic forces are discussed inside the wind tunnel with miniature dimensions. The problem, which is checked in this article, is the investigation the effect of surface deformation in a small airfoil. In order to validate the tunnel, a flat plate is examined in the miniature wind tunnel test section and the experimental results are reported with the existing results with an error of less than 10%. The selected sample of airfoils is one of simple small airfoils and another example is smart . The selected structure material for both small airfoil samples is balsa wood and thermal coating is used for the shell. The test section is analyzed and investigated with simple small airfoil. The next step include the design, fabrication, and finally, the evaluation of the smart small airfoil in the test section.
Research Article
Propulsion/Thermodynamics/Heat Transfer/Fuel and Combustion/Energy/...
Mohsen Esfandi; Mohammad Kazem Moayyedi
Articles in Press, Accepted Manuscript, Available Online from 09 June 2023
Abstract
In this study, the simulation of internal ballistics and the exhaust flow of a solid propellant engine have been investigated. The flow field considered in this problem including the cylindrical grain and the solid wall of the engine and the flow at the nozzle outlet have been studied. The governing ...
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In this study, the simulation of internal ballistics and the exhaust flow of a solid propellant engine have been investigated. The flow field considered in this problem including the cylindrical grain and the solid wall of the engine and the flow at the nozzle outlet have been studied. The governing equations are used in an axisymmetric and compressible form to model the fuel combustion in non-erosive combustion mode. In the present study, cylindrical type of grain fuel is considered, which is one of the most useful types of fuel grains in terms of simplicity in production. In order to obtain the results from the simulation model which are close to the real data, used UDF modules in the Fluent software to describe some specific quantities and phenomena of the problem. Finally, the results obtained from the simulation in different modes of fuel burning are examined and show the accuracy of the numerical model by entering the parameters affecting the fuel burning.
Research Article
Flight mechanics/Navigation/Control/...
mohamad mahdi soori; seyed hosein Sadati
Articles in Press, Accepted Manuscript, Available Online from 09 August 2023
Abstract
This article describes the process of designing and simulating the performance of the predictive controller of the optimal model, which was created in order to guide the missile in a two-dimensional problem of minimizing the collision time and the distance from the target. In the design of the optimal ...
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This article describes the process of designing and simulating the performance of the predictive controller of the optimal model, which was created in order to guide the missile in a two-dimensional problem of minimizing the collision time and the distance from the target. In the design of the optimal model predictive controller, first the widely used type of implicit linear predictive model is designed and then the nonlinear predictive model is presented and their performance in missile guidance is evaluated. According to the simulations, it can be shown that the predictive controller of the implicit linear model (on-line) and the predictive controller of the optimal non-linear model control the distance of the missile's final collision with the target and the collision time well. The innovation of this article is the design of the predictive controller of the optimal model using genetic algorithm and particle community in the integrated guidance and control model.
Research Note
Structure/Solid Mechanics/Solid Dynamics/Vibrations/Aeroelasticity/...
Saeed Tarhani; Mahdi Karami Khorramabadi
Articles in Press, Accepted Manuscript, Available Online from 23 August 2023
Abstract
In this research, the impact strength of functionally graded epoxy/graphene nanocomposite have been investigated. First, the samples were made for uniform and functionally graded distributions. Then, the distribution of nanoparticles has been investigated using a scanning electron microscope. Based on ...
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In this research, the impact strength of functionally graded epoxy/graphene nanocomposite have been investigated. First, the samples were made for uniform and functionally graded distributions. Then, the distribution of nanoparticles has been investigated using a scanning electron microscope. Based on this investigation for uniform distribution up to 1.5% by weight of graphene nanoparticles, no signs of agglomerated particles were found. In addition, imaging was also done for the functionally graded sample and it was observed that the boundary of the layers is completely connected. Then the samples were subjected to Izod impact test and it was observed that for uniform distribution, the amount of energy absorption increased up to 1% by weight of graphene nanoparticles and then for the sample with 1.5% by weight of graphene nanoparticles, its value started to reduces. To validate the accuracy of the obtained results, modeling has been done for the mentioned samples using the finite element method and the obtained results have been compared with the experimental results.
Research Article
Flight mechanics/Navigation/Control/...
M. Barati; Mehdi Sabzehparvar; M. Navabi
Articles in Press, Accepted Manuscript, Available Online from 18 October 2023
Abstract
In order to perform attitude control ground experiments, it is crucial to ensure the center of mass of the platform is coincident with the center of rotation as accurate as possible. In this paper, a linearized dynamic model of the imbalanced attitude platform is derived and a linear controller is methodically ...
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In order to perform attitude control ground experiments, it is crucial to ensure the center of mass of the platform is coincident with the center of rotation as accurate as possible. In this paper, a linearized dynamic model of the imbalanced attitude platform is derived and a linear controller is methodically designed to stabilize the system by mass relocation. The stability conditions of the system under the proposed controller are derived. The balancing procedure starts with a parameter estimation method to estimate the center of mass offsets. Next, the PD controller is applied to align the platform’s horizontal plane with the local horizontal level. Finally, the imbalance in vertical axis can be estimated and compensated to complete the automatic mass balancing. Actuator limitations and nonlinear equations of motion are implemented in numerical simulations and the results demonstrate the effectiveness of the proposed method in significantly reducing the residual imbalance torque on the simulated platform.
Scientific extension
Other Related Fields
Saman Yazdannik; Morteza Tayefi
Articles in Press, Accepted Manuscript, Available Online from 01 October 2023
Abstract
: In the contemporary landscape, the utilization of multi-rotor drone technology has witnessed a notable upsurge across diverse academic, industrial, and commercial domains. These multifaceted systems have assumed pivotal roles encompassing surveillance, wireless network coverage, remote sensing, search ...
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: In the contemporary landscape, the utilization of multi-rotor drone technology has witnessed a notable upsurge across diverse academic, industrial, and commercial domains. These multifaceted systems have assumed pivotal roles encompassing surveillance, wireless network coverage, remote sensing, search and rescue operations, efficient package delivery, tele-medicine facilitation, security enforcement, monitoring, precision agriculture, traffic management, and infrastructure inspection, among others. The trajectory of technological advancement underscores the impending significance of intelligent quad-copters as a transformative force within the industry, promising to forge novel avenues and redefine conventional paradigms. In effect, this paradigm shift is poised to mitigate operational risks and financial outlays, thereby fostering heightened assimilation of these technological innovations. Projections underscore that drones' market penetration within the civil infrastructure sector is slated to culminate in an approximately $45 billion valuation by end of this decade. This discourse delves into an all-encompassing exploration of the manifold applications and associated challenges intrinsic to multi-rotor systems, with a particular emphasis on quad-copters, across research arenas and diverse industries. Furthermore, the discourse offers an incisive analysis of prevailing trends while shedding light on the contours of forthcoming developments in the utilization of these transformative devices.
Scientific extension
Maintenance of Engine, Wings and Fuselage of Aircraft/Technology/Manufacturing/...
mehdi jafari; Amirreza Ardebili; Amir Kaveh
Articles in Press, Accepted Manuscript, Available Online from 09 July 2023
Abstract
Components of the LEO environment consisting of high vacuum, ultraviolet radiation, thermal cycles, Atomic Oxygen, charged particles, electromagnetic radiation, micrometeorites, and space debris significantly degrade the material properties of polymer matrix composite materials. Therefore, in the design ...
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Components of the LEO environment consisting of high vacuum, ultraviolet radiation, thermal cycles, Atomic Oxygen, charged particles, electromagnetic radiation, micrometeorites, and space debris significantly degrade the material properties of polymer matrix composite materials. Therefore, in the design of space structures using composite materials, the possible deterioration of mechanical properties due to long-term exposure in LEO space environment should be carefully considered. Accordingly, a reliable understanding of the LEO environment in its effects on composite materials as well as investigating its properties is very important. The space simulator system under vacuum is designed with the aim of creating a standard environment with the ability to reach high vacuums and also the ability to create low temperatures, as well as to check the qualification of space components and research materials used in the satellite. These systems analyze the behavior of satellite components, evaluate their thermal balance and performance to ensure mission success and survivability.
Research Article
Maintenance of Engine, Wings and Fuselage of Aircraft/Technology/Manufacturing/...
Hamid Reza Zarei; Mostafa Livani; Meysam Jalalvand
Articles in Press, Accepted Manuscript, Available Online from 17 October 2023
Abstract
Abstract: In this article, to investigate the severity of damage to the helicopter pilot under the crash impact, the numerical simulation of the real helicopter cockpit seat has been done. To limit the complexity of the problem, a fully vertical impact was considered as a reference scenario for the assembly ...
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Abstract: In this article, to investigate the severity of damage to the helicopter pilot under the crash impact, the numerical simulation of the real helicopter cockpit seat has been done. To limit the complexity of the problem, a fully vertical impact was considered as a reference scenario for the assembly consisting of a collapsible helicopter seat, energy absorption section and a humanoid dummy. For this purpose, the three-dimensional model of the chair in the laboratory was studied in two states with and without the addition of the energy absorption mechanism. Honeycomb structure was used in the seat cushion section. The results of the research showed that the use of UPVC damper to test the crash impact with a certain mass based on biomechanical criteria, an average 80 % decrease in serious injuries to the skull and spine has been achieved. Also, although the aluminum honeycomb structure meets the criterion of damage to the head and is within the permissible range, it has rejected the criteria of damage to the spine and permissible acceleration range. However, compared to the case without honeycomb, it has performed much better and has been able to absorb the energy of the crash impact.
Scientific extension
Space Engineering/Space Orbit Mechanics/Space Sciences/...
pourya shokrolahi; Masoud Ebrahimi
Articles in Press, Accepted Manuscript, Available Online from 05 November 2023
Abstract
The space testbeds have been a milestone in space missions. The development of laboratory testbeds capable of testing space missions has led to increased reliability and performance of space systems during their missions. This article presents a review study on space testbeds, with a particular focus ...
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The space testbeds have been a milestone in space missions. The development of laboratory testbeds capable of testing space missions has led to increased reliability and performance of space systems during their missions. This article presents a review study on space testbeds, with a particular focus on rendezvous and docking laboratory testbeds. In this study, the testbeds have been categorized into two-dimensional and three-dimensional platforms. The table-based frictionless platforms, robotic simulation platforms, and the combination of a table and a rail structure are categorized under the two-dimensional platforms. The three-dimensional category also includes robotic arm-based platforms, water pools, free gravity or micro gravity environments, rail in a three-dimensional environment, and unmanned aerial vehicles. Considering the importance of developing and implementing laboratory testbeds for space missions and rendezvous and docking, at the end, the article has introduced the testbeds based on categorization. It also provides examples of existing laboratories, as well as samples of active institutions and centers in this field.
Research Article
Maintenance of Engine, Wings and Fuselage of Aircraft/Technology/Manufacturing/...
Jamshid Fazilati
Articles in Press, Accepted Manuscript, Available Online from 13 November 2023
Abstract
Toroidal propellers are among the ideas recently introduced by MIT-Lincoln Center for aerial applications. It is claimed that this design significantly reduces the annoying noise level compared to the conventional bladed propellers by eliminating the fluid escape points at the blade ends. Due to the ...
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Toroidal propellers are among the ideas recently introduced by MIT-Lincoln Center for aerial applications. It is claimed that this design significantly reduces the annoying noise level compared to the conventional bladed propellers by eliminating the fluid escape points at the blade ends. Due to the importance of reducing environmental footprint of flying robots, this design paradigm can be particularly advantageous wherever the noise pollution is a concern. This will result in the adoption of drones for various applications. In this study, with the aim of identifying this modern type of design, the process of prototyping and testing a set of the toroidal propellers has been carried out. The main functional parameter of interest in this study is thrust. For the sake of comparison, samples of common bladed propellers have also been produced and tested. As a quick and accessible method for prototyping, the propellers have been made by additive manufacturing using a 3D printer. In the assessment process, simultaneous measurement of the motor speed and thrust have been performed. Finally, performance graphs for all propellers have been extracted and compared. The results showed that the three-ring toroidal propeller with slightly more weight, provides more thrust than the conventional three-bladed propeller.
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