The present study evaluates and investigates the fatigue design and fatigue life as the crack propagation occurs around the fastener of the mainframe of the central fuselage (CTR) of a rotary-wing aircraft designed based on the conventional safe-life method. For this work, the static and dynamic strain data were acquired according to flight conditions and fastening conditions between the mainframe

A distributed time cooperative guidance method based on the finite-time control theory is proposed to solve the salvo attack problem of multi-hypersonic vehicles in the three-dimensional space. Firstly, the second-order system is defined with the relative distance and the total leading angle as the state variables, and the finite-time controller is designed based on the multi-agent cooperative control

This study proposes a framework for designing/optimizing a Lunar rover for an early-phase mission concept trade-off. The proposed framework (1) develops models for major rover subsystems and lunar environment, (2) generates the rover’s operational schedule using the models, and (3) yields a set of attractive design solutions. The framework adopts a Pareto search algorithm to find the Pareto-optimal

As a part of emergency landing architecture for multi-rotor, a fault-tolerant trajectory tracking control strategy is proposed in this paper to control a quadcopter in case of a partial motor fault. The introduction of fault-tolerant strategy includes a lightweight fault detection and identification algorithm and a three-loop tracking controller. The lightweight fault detection and identification algorithm

The structural behavior and safety of a static load test fixture for a pylon and an external fuel tank of a fixed-wing aircraft currently being developed in South Korea are analyzed. The test loads are calculated via the flight loads applied on the external fuel tank and a whiffletree configuration; subsequently, they are used in the static analysis of the test fixture using the finite element method

How to establish a general fuel tank thermodynamic model that meets the requirements of airworthiness certification and how to obtain the equilibrium temperature difference △T and time constant τ in the Monte Carlo evaluation model after obtaining the fuel temperature change law within specific flight envelope are the bottleneck issues need to be solved urgently in the airworthiness certification process

Ballistic range experiments were performed for a hemisphere-flare-cylinder model at supersonic Mach numbers in the transitional Reynolds number range at Nagoya University. The free-flight portion was modelled as axisymmetric in ANSYS Fluent® V.19.0. Projectile deceleration was included in the simulation as a function of the drag force over an approximate flight Mach number range 2.0–1.90. The projectile

A numerical method combining computational fluid dynamics (CFD) method and Ffowcs Williams–Hawkings (FW–H) equations is established for predicting acoustic characteristics of the coaxial rigid rotor in hovering and forward flight. The unsteady Reynolds-averaged Navier–Stokes (URANS) solver coupled with the moving-embedded grid technique is established to obtain sound source information in the flowfield

This paper presents an indirect estimation based active disturbance rejection control (ADRC) for solar sail station-keeping. In contrast to previous applications of ADRC to spacecraft station-keeping the proposed approach estimates the deviation of the orbit state from the reference orbit, instead of estimating the orbit state directly. Since the deviation of the orbit state varies more slowly than

At present, the design and optimization of the linear explosive separation device mainly depends on experiment, which is not only costly but also low efficient. The introduction of finite element analysis prior to experiment may reduce the cost to design a linear explosive separation device. Herein, arbitrary Lagrangian–Eulerian (ALE) numerical method is utilized to investigate the functioning of an

Aiming at the problem of UAV formation's obstacle avoidance and the consensus of position and velocity in a 3D obstacle environment, a novel distributed obstacle avoidance control algorithm for cooperative formation based on the improved artificial potential field (IAPF) and consensus theory is proposed in this paper. First, the particle model of the UAV and the dynamic model of the second-order system

Design sensitivity analysis of static aeroelastic stresses constitutes an important issue for the gradient-based integrated design optimization of wing structure, and can be analytically performed using a new modified stiffness matrix. However, introducing a modified stiffness matrix into the calculation will give rise to additional computational effort. Additionally, the direct method is incompetent

This paper presents the Power Plant Trio (PPT) Can Satellite (CanSat) platform developed by the University of Chosun, South Korea, with a focus on energy harvesting systems. The main objective of this project is to confirm the effectiveness of solar, wind and piezoelectric energy harvesting systems, which are utilized for LED lighting and activating a self-powered MEMS-based sensor module. The secondary

When using GNSS navigation for final approach guidance of aircraft to a landing site, the only systems currently available are differential GNSS with additional integrity data called augmentation systems. These work well when the landing site is fixed in space and well surveyed. In all other cases, augmentation systems are difficult to use. Here, we propose relative navigation based on GNSS double

Reducing aircraft weight for engineering and manufacturing processes is very important but challenging. To solve this problem, a weight-reduction optimization design method for aircraft side panels based on orthogonal experiments and finite-element analysis was proposed for the first time in this paper. The design factors of the aircraft side panels and the layout of composite materials were comprehensively

In this study, we investigate optimal receive combining methods that use additional ground antennas in a dual-contact satellite scenario in which a target satellite and an adjacent satellite simultaneously transmit their data to ground antennas at the same location. When the adjacent satellite is within the looking angle of the ground antenna of the target satellite, interference causes the performance

The process of obtaining flight data from flight test is complex and costly, which makes it difficult to identify aerodynamic parameters. Therefore, Cessna172 flight simulator was used for flight data extraction, which ensures the convenience, efficiency and economy of the test. To obtain aerodynamic model, based on the idea of machine learning, a recurrent neural network was used to process multi-dimensional

Single Image Super Resolution (SISR) elevates spectral and spatial image resolution beyond the sensor capabilities. Convolutional Neural Networks (CNNs) have dominated current mainstream approaches. However, the utilization of pixel-based loss function hinders achieving realistic perceptual results at large upscale factors. Recently, Generative Adversarial Network (GAN) attained more realistic, crisp

Pyrotechnic separation devices are widely used in space separation systems. However, these devices produce high-frequency, high-amplitude shock responses during operation, which endangers the safety of space systems. Hence, it is imperative to study the shock mechanism and characteristics during the unlocking process of a pyrotechnic separation device. This paper uses LS-DYNA finite element software

Fluid sloshing usually causes some serious safety issues during the transportation and utilization of liquid fuel in different engineering applications. In this paper, a computational fluid dynamics model is established to investigate the thermal physical process and sloshing hydrodynamics in a cryogenic fuel storage tank. Both the experimental validation and calculation grid sensitive analysis are

A data-driven statistical analysis of the missile’s capture region is performed. The capture region is the region of the initial geometric configuration for pursuer missile against a target in which the missile can intercept the target while satisfying specific constraints. The statistical verification approach has advantages over the analytic approach in that it can deal with various guidance algorithms

This paper presents a robust path following control law that enables a fixed-wing UAV to track a reference path under the wind disturbance. The proposed path following control law combines the kinematic control law for regulating the distance error to the moving reference point and the command-filtered backstepping scheme for obtaining the roll command of the UAV. Unlike the conventional backstepping

A cable-driven model support concept is suggested and implemented in this paper. In this case, it is a cable suspension and balance system (CSBS), which has the advantages of low support interference and reduced vibration responses for effective wind tunnel tests. This system is designed for both model motion control and aerodynamic load measurements. In the CSBS, the required position or the attitude

In this study, we analyzed the effect of a single overload fatigue cycle on the efficiency of bonded composite patch repair on a cracked Al 2024 T3 aluminum plate. Experimental and numerical analyses were performed to achieve the objective of the study. In the experimental part of the study, fatigue tests were conducted on a V-notched aluminum plate subjected to a constant amplitude fatigue loading

Rotor assembly is a core tache in the whole process of aero-engine manufacturing. Preventing out-of-tolerance of concentricity is one of the primary tasks. Conventional assembly approaches are based on a manual test with the dial indicator, depending on experience appraises, which lack systematic and quantitative precision design theory. As a result, two issues need to be solved: the modeling problem

This paper explores the effectiveness of spin motion in mitigating the flight dispersion of a two-stage solid-propellant rocket model due to thrust misalignment. The aerodynamic coefficients of the rocket model are obtained by the use of a panel method and semi-empirical equations. A simulation program is developed to solve the equations of motion while considering the variations of the inertial parameters

The response of composite T-joint specimens to hydrodynamic ram testing is investigated in this study. A hydrodynamic ram is one of the major manmade threats to aircraft structures, particularly to fuel systems, which are the most vulnerable to ballistic battle damage. As composite materials are increasingly being used in aircraft structures, survivability-enhanced structural designs, particularly

This study considers a mobile platform effect on a bifolded wing deployment. An additional velocity induced by a mobile launch platform was applied. Therefore, aerodynamic moments on a deploying bi-folded wing were calculated with wind-over-deck velocity, a vector sum of the platform velocity and the wind velocity. In the calculation, the panel method is applied to obtain the moments for quick aerodynamic

A correction to this paper has been published: https://doi.org/10.1007/s42405-021-00381-z

This study aims to investigate the influence of flight altitude on the plume radiation enhancement effect caused by afterburning. The infrared radiation simulation model consisting of the standard \(k - \varepsilon\) two-equation turbulence models, the finite velocity model, and the finite volume method (FVM) was established in this work. Based on the proposed model, the influence of afterburning on

Numerical simulations are performed to investigate the effects of different RPM (revolutions per minute) and different diameter on aerodynamic performances of tiltrotor in both hovering and cruise flight modes. The CLORNS code based on embedded grid and Reynold averaged Navier–Stokes equations is employed. According to the flight state of the tiltrotor, the corresponding comprehensive performance evaluation

Modern unmanned aerial vehicles (UAVs), including combat drones, are usually equipped with cameras for imaging. A camera is mainly used to increase the accuracy of the attack by ensuring stable-guided flight toward the target when the UAV detects the target in the terminal phase. Despite the high cost of these pieces of equipment, their utilization is in fact low, except during the final stage. The

Large droplet dynamics, such as droplet–wall interactions and droplet breakup, have a significant impact on the icing process, under super-cooled large droplet (SLD) conditions. Accordingly, many studies have been conducted to numerically implement the effects of large droplet dynamics on the 2nd generation icing codes. Most of them have focused particularly on droplet–wall interactions, while breakup

Textile composites are applied to aerospace and automotive industries because they have good fatigue characteristics, and higher specific stiffness and strength compared to metallic materials. In addition, textile composites have better out-of-plane performances such as the resistance of impact and inter-laminar delamination, in addition to greater structural flexibility than the traditional unidirectional

In this study, a pattern for an active frequency selective surface (AFSS) applicable to stealth radomes was designed and manufactured. Subsequently, its effectiveness was verified via measurements of its electromagnetic performance, and its mechanical performance was numerically evaluated in an actual flight environment. An AFSS equipped with a PIN diode was designed to have a transmission frequency

Reliability analysis is a specific field of statistics that studies failure time and its probability on a system. This branch of statistics takes an important place in many domains, especially in aeronautics. One of the most commonly used methods of reliability analysis is the hazard function which is defined for a specific instance in time, given the information up to that moment. Commonly, the most

A digital elevation model (DEM) can be generated using a gradient of a single image and a stereo image pair from an imaging sensor or laser altimeter sensor on an orbiter. These DEMs are affected by intrinsic problems such as stereo noise in the triangulation process or low spatial resolution from sparse measurement points. Various image-based techniques are presently used to enhance the resolution

This paper addresses an impact angle control guidance problem for nose-dive missiles to achieve the maximum terminal speed against a fixed target in the same vertical plane. By modeling the aerodynamic drag as a drag polar, we set up the nonlinear system equations needed to pursue an analytic closed-form solution. This paper shows that maximizing the terminal speed is equivalent to minimizing a weighted

The coupling between different disciplines for multi-disciplinary optimization greatly increases the complexity of a computational framework, while at the same time increasing CPU time and memory usage. To overcome these difficulties, first, proper orthogonal decomposition and radial basis function were used to generate a reduced-order model from the initial experimental points. Second, analysis results

To model 3-Dimensional woven composites, the width and thickness of the yarn are generally used as input parameters. However, since these parameters can only be obtained after the composites are molded, it is not efficient in the initial stages of design using woven composites. Therefore, a geometric modeling method using weaving parameters that can be known before manufacturing is required. In this

In this paper, a novel adaptive fast nonsingular terminal sliding mode (FNTSM) control approach is proposed for the robust adaptive finite-time prescribed performance attitude tracking control of spacecraft subject to inertia uncertainties, external disturbances, and input saturation. First, a simple error transformation is introduced to guarantee the attitude tracking errors always stay within the

In this paper, a linear acceleration control algorithm is proposed. The proposed algorithm aims to follow a given linear acceleration command accurately to enable precise trajectory tracking flights especially for a quadrotor unmanned aerial vehicle under high-wind environments. Existing linear acceleration control algorithms are based on feedforward control concept only, however the proposed algorithm

A previously developed estimation technique, of the minimum energy required for complete fin deployment under an operational requirement of gust speed, was modified to consider time consumed for fin unfolding as an additional requirement, which might lead to an increase of the required energy. Some modifications were made such as non-zero kinetic energy of unfolding fin when completely deployed and

This paper proposes an integrated framework for staging and trajectory optimization of a launch vehicle under a constraint on the instantaneous impact point (IIP) of the separated stage. The proposed framework iterates between the optimal staging module and the trajectory optimization module to minimize the lift-off mass of a launch vehicle for a given payload mass. The trajectory optimization module

To improve the aerodynamic performance of tiltrotor aircraft, the flow characteristics of the V-22 airfoil without and with one, two parallel rows of vortex generators (VGs) were investigated using numerical simulation methods. The results were obtained with three-dimensional compressible Reynolds-averaged Navier–Stokes equations, and the turbulence was simulated with the SA-based DES model. The influence

Multi-packet whole bladed disks are found in some turbo engines. At the same time, mistuning of blades is inevitable and it will lead to the vibration localization in which vibration energy mainly locates in some blades in the bladed disk system. It can accelerate the high cycle fatigue of the bladed disk. It is critical to search for an efficient way to control the level of vibration localization

Compared with UAVs controlled by aerodynamic surfaces, mass-actuated UAVs have higher aerodynamic efficiency and better stealth performance. This paper focuses on the dynamics and attitude control of a mass-actuated fixed-wing UAV (MFUAV) with an internal slider. Based on the derived mathematical model of the MFUAV, the influence of the slider parameters on the dynamical behavior is analyzed, and the

A new method to estimate the aircraft heading angle, wind velocity, and airspeed bias error is proposed without relying on the magnetometer. A GPS, rate-gyro, pitot-static tube, and sideslip angle sensor are combined through a design of an extended Kalman filter based on a vectorial geometric relation among the ground, air, and wind velocity. The feasibility of the method is validated through a desktop

Rotors with active flap control have considerable potential in reducing vibration and noise and improving aerodynamic performance. However, due to the movement of the flap, there are unavoidable gaps between the components that will lead to significant changes in the aerodynamic characteristics. Moreover, considering the difficulties in motion modeling and the accuracy of the simulation of the flow

To achieve supermaneuverability, the flight envelope for modern fighter aircraft should be extended beyond 40 \(\sim \)60° angles of attack region, where unstable and undesirable flight characteristics such as wing rock may occur. This paper investigates the wing rock phenomenon of a fighter configuration having conventional conical forebody through free-to-roll (FTR) wind tunnel tests. The time history

Research on cooperation missions of multiple unmanned vehicles (UVs) is growing to overcome the limitations of conventional missions and to increase the variety of missions. In this study, a vision-based recognition and position measurement system was developed to cooperate with an unmanned aerial vehicle (UAV) in case an unmanned ground vehicle (UGV) is unable to drive due to terrain obstacles. Phase

With the development of supersonic/hypersonic vehicles, the influence of non-uniform flow has attracted increasing attention. Non-uniform flow exists everywhere in a scramjet, which is a potent engine for supersonic/hypersonic vehicles. Most flows entering the isolator, combustor, and nozzle exhibit high non-uniformity. Thus, several design methods for generating non-uniform flow have been proposed

In this study, we proposed concepts of a vertiport airspace design that must precede for the practical operation of urban air mobility, an emerging new urban mobility solution. We developed algorithms to find the optimal radius of airspace for each concept and, through simulations, derived comparisons among them. We also introduced the concept of a vertiport terminal control area where an personal

Two-dimensional numerical simulations of a nanosecond pulsed single dielectric barrier discharge (SDBD) are performed in air. Streamers produced in nanosecond SDBDs have filamentary properties and generate a strong electric field and high-density gradient of charged particles. This results in non-equilibrium effects of electrons, which makes analysis of the plasma physics challenging. To simulate the

Understanding the effect of fluctuating wind on the aerodynamic performance of the wing is important for designing practical using flapping-wing micro air vehicles (FMAV). This paper aims at providing a systematic synthesis on the fluctuating wind influence on the performance of the three dimensional lumped flexibility wing based on the numerical analysis approach. The fluctuating wind is simplified

This paper addresses the control issue of the integrated attitude and orbit tracking of spacecraft in the presence of inertia parameter uncertainty and spatial disturbance. By considering thruster as the control actuator, the 6-degree-of-freedom integrated model consisting of attitude and orbit dynamics is formulated. Based on the backstepping design, an adaptive control strategy is developed by exploiting

To solve a problem of bi-criteria optimization of an aircraft flight trajectory using the data of satellite navigation systems, the authors suggest an approach based on the game theory methods. The target was set to organize trajectory control with two partial criteria of optimality (desired track deviation and position-fixing error) minimized simultaneously. It is shown that the minima of individual

Delayed detached eddy simulation (DDES) has been proved to be suitable for the numerical simulation of massively separated flow. Whereas, there are still some drawbacks in the treatment of gray area, which is the transition zone between Reynolds-Averaged Navier–Stokes (RANS) and large eddy simulation (LES). In this paper, a modified DDES with shear layer adapted (SLA) subgrid length scale was employed

This study aims to develop a simple and efficient design optimization methodology for the low Reynolds number airfoils. XFOIL is used as an aerodynamic solver while modeFRONTIER workflow is employed for the design optimization purpose. The airfoil SG6043 is used as the reference airfoil for optimization due to its common applications when long-endurance characteristics are desired. A simple design

This paper proposes a practical optimal guidance law that can handle terminal angle and acceleration constraints while providing robustness against uncertainty in autopilot dynamics. Building upon a well-established linear-quadratic optimal guidance framework, we first derive an energy-minimizing guidance scheme that nullifies terminal acceleration called optimal guidance law with impact angle and