Showing papers in "Journal of Aerospace Engineering in 2022"
TL;DR: In this paper , the authors used Viscoelastic dampers, as a common shock absorber, to detect damage to high-rise buildings, and showed that they can be used to detect structural damage.
Abstract: AbstractBecause shock absorbers are an important component of high-rise buildings, it is essential to be able to detect damage to them. Viscoelastic (VE) dampers, as a common shock absorber, direct...
14 citations
TL;DR: In this article, the Viscoelastic (VE) dampers, as a common shock absorber, are used to detect damage to high-rise buildings, which is essential to be able to detect damages to them.
Abstract: Because shock absorbers are an important component of high-rise buildings, it is essential to be able to detect damage to them. Viscoelastic (VE) dampers, as a common shock absorber, direct...
14 citations
TL;DR: In this article , the ground effect on the leading-edge vortex characteristics of a 40° swept delta wing was analyzed at two angles of attack, 8° and 11°, and the space between the ground and lower surface of the wing was nondimensionalized with the wing's chord length.
Abstract: The ground effect influences the flow structure on a delta wing during landing and take-off processes. In this regard, comprehensive instantaneous velocity measurements and flow visualizations were carried out by particle image velocimetry and dye flow visualization techniques to reveal the ground effect on leading-edge vortex characteristics of a 40° swept delta wing. The flow behaviors on the delta wing under the impact of the ground were analyzed at two angles of attack, 8° and 11°, and the space between the ground and lower surface of the wing was nondimensionalized with the wing’s chord length. It was found that the presence of the ground caused premature leading-edge vortex breakdown due to the increasing adverse pressure gradient on the wing’s suction side along the chord direction. The ground effect caused an increase in peak value and distributions of turbulent kinetic energy on the wing surface that depended on the earlier leading-edge vortex bursting and complex and disorganized flow structures. The value of time-averaged vertical velocity was lower when the delta wing descended from the free-stream flow zone into the ground effect zone because of the blocking of fluid flow in the gap between the ground and pressure surface of the wing. Thus, it can be concluded that the ground effect is very influential on the change of vortical flow characteristics of nonslender delta wings.
12 citations
TL;DR: A robust adaptive predefined-time control scheme for spacecraft rendezvous maneuvers with the consideration of input saturation and external disturbances is proposed.
Abstract: This paper proposes a robust adaptive predefined-time control scheme for spacecraft rendezvous maneuvers with the consideration of input saturation and external disturbances. To ensure the ...
7 citations
TL;DR: In this article, the robust continuous fractional-order nonlinear sliding mode (RCFONSM) control scheme for controlling a disturbed uncertain quadrotor (DUQ) was investigated.
Abstract: This paper investigates the robust continuous fractional-order nonlinear sliding mode (RCFONSM) control scheme for controlling a disturbed uncertain quadrotor (DUQ). First, the fractional-o...
6 citations
TL;DR: In this paper , a non-unique relationship between the density and quasi-static strength of Miura-ori metamaterials was explored for graded materials with respect to quasistatic and dynamic in-plane compression.
Abstract: The non-unique relationship between the density and quasi-static strength of Miura-ori metamaterials was explored for graded materials with respect to quasi-static and dynamic in-plane compression. A lower bound estimate of quasi-static strength and energy absorption was obtained using an analytical method by only considering the deformation mechanism of the rigid origami motion. Graded origami metamaterials were achieved by applying either a variation of the initial folding angle or a variation of the thicknesses of cell walls in the loading direction. It was shown that grading by a moderate increase of the initial folding angle does not notably contribute to the overall material strength and consequently to an improvement of the energy absorption efficiency of the metamaterial under quasi-static compression. Grading by wall thickness variation leads to a notable strength increase and moderately enhanced energy absorption. It is shown that the significant strength gradient leads to a violation of the rigid motion rule and the cells collapse sequentially, which has been validated by test results published in the literature. Different from quasi-static behavior, the response of the Miura-ori metamaterial to relatively high velocity impact is governed by the density gradient values, regardless of the grading technique. Furthermore, the differently graded profiles (positive or negative) affect the force-displacement histories but not the energy absorption efficiency of the examined metamaterials.
6 citations
TL;DR: In this article, the authors examine the brittle failure mechanisms of polymeric materials used in fiber-reinforced composite structures under various loading scenarios, and find that they are vulnerable to various loading conditions.
Abstract: To understand the response of polymeric materials used in fiber-reinforced composite structures, it is necessary to examine their brittle failure mechanisms under various loading scenarios....
6 citations
TL;DR: In this paper , the robust continuous fractional-order nonlinear sliding mode (RCFONSM) control scheme for controlling a disturbed uncertain quadrotor (DUQ) is investigated.
Abstract: This paper investigates the robust continuous fractional-order nonlinear sliding mode (RCFONSM) control scheme for controlling a disturbed uncertain quadrotor (DUQ). First, the fractional-order nonsingular terminal sliding mode (FONTSM) manifolds are designed for the altitude and attitude, and a finite-time convergence is realized in the sliding mode phases of the DUQ system. Then, based on fast terminal sliding, reaching laws are proposed to enhance the tracking performance against disturbances and ensure finite-time convergence in the reaching phases of the DUQ system. The proposed robust continuous fractional-order nonsingular terminal sliding mode (RCFONTSM) switch element may effectively improve the dynamical performance of the fractional-order nonlinear sliding mode (FONSM) surface by substituting the integral and derivative operators with fractional-order operators for the error dynamics. The Lyapunov theory is used to prove the stability of the tracking errors and the stabilization of the DUQ simultaneously. The proposed sliding manifolds and fast reaching laws ensured good robustness against disturbances/uncertainties, fast convergence, and high precision. Numerical simulation of the proposed controller compared with fractional-order (FO) backstepping sliding mode control (SMC) is given to demonstrate the superiority of the RCFONSM.
6 citations
TL;DR: A passive fault tolerant attitude control is investigated for a nano-satellite with three magnetorquers and one reaction wheel in the presence of actuator constraints, extern...
Abstract: In this paper, a passive fault tolerant attitude control is investigated for a nano-satellite with three magnetorquers and one reaction wheel in the presence of actuator constraints, extern...
5 citations
TL;DR: In this article, the authors consider practical aspects of mathematical modeling in predictions of the level of near-field pressure pulsations of a near-future prototype supersonic business aircraft.
Abstract: The paper considers practical aspects of mathematical modeling in predictions of the level of near-field pressure pulsations of a near-future prototype supersonic business aircraft. A numer...
5 citations
TL;DR: In this article , the response of polymeric materials used in fiber-reinforced composite structures is examined under various loading scenarios, and their brittle failure mechanisms are examined under different loading scenarios.
Abstract: AbstractTo understand the response of polymeric materials used in fiber-reinforced composite structures, it is necessary to examine their brittle failure mechanisms under various loading scenarios....
TL;DR: In this article , the authors proposed a smart sliding mode controller for a novel kind of quadcopter called tilt-rotor quadcopters, which is modeled in SIMULINK and implemented on a Pixhawk 2 flight controller board.
Abstract: This paper proposes a sliding mode controller for a novel kind of quadcopter called tilt-rotor quadcopter. The controller is modeled in SIMULINK and implemented on a Pixhawk 2 flight controller board. First, this paper presents the dynamic model of the tilt-rotor quadcopter. Second, the proposed smart sliding mode controller for simulation studies is presented. Third, the hardware platform is discussed in detail with the controller implementation. Finally, numerical simulation results for the smart sliding mode controller for various scenarios (wind disturbances, faulty motors) are presented following which the preliminary hardware tuning results are presented. Simulation results of the tilt-rotor platform hovering at a position with a nonzero attitude are also shown. This paper also presents a discussion on the challenges faced transitioning from a simulation environment to hardware testing and plausible ideas to address the challenges.
TL;DR: It is seemingly inevitable that one day humans will land on the surface of Mars as mentioned in this paper, between the Apollo lunar missions, International Space Station, and Martian rovers and landers, much of the...
Abstract: It is seemingly inevitable that one day humans will land on the surface of Mars. Between the Apollo lunar missions, International Space Station, and Martian rovers and landers, much of the ...
TL;DR: In this paper, a high-resolution numerical study of the effects of rotor blade surface blow-off is presented, where the authors present a high resolution numerical analysis of the BVI interaction.
Abstract: Reducing rotor blade–vortex interaction (BVI) noise is a major challenge in rotorcraft research. This paper presents a high-resolution numerical study of the effects of blade surface blowin...
TL;DR: In this paper , an incremental nonlinear dynamic inversion is improved and utilized to solve the six-degrees-of-freedom waypoint tracking problem of fixed-wing UAVs.
Abstract: Incremental nonlinear dynamic inversion shows good robustness and low dependence on the model information. In this study, incremental nonlinear dynamic inversion is improved and utilized to solve the six-degrees-of-freedom waypoint tracking problem of fixed-wing unmanned aerial vehicles (UAVs). This research is focused on studying the acquisition of the state derivatives and the processing method of the derivative time delay. A nondelay differentiator design method and an incremental gain method that responds to time delay are developed in this study. Additionally, a universal waypoint navigation method based on incremental nonlinear dynamic inversion is put forward to enable the aircraft to successfully reach its waypoint from any spatial position and under any motion states. Finally, the proposed improvements of the incremental nonlinear dynamic inversion are verified through flight tests.
TL;DR: In this paper , higher-order dynamic mode decomposition (HODMD) was applied to find the main patterns and frequencies of a transient aerodynamic flow field when an aircraft wing experiences stall.
Abstract: In this paper, higher-order dynamic mode decomposition (HODMD) was applied to find the main patterns and frequencies of a transient aerodynamic flow field when an aircraft wing experiences stall. This method was applied to a computational flow simulation with a turbulence model based on a hybrid Reynolds-averaged Navier-Stokes large-eddy simulation (RANS/LES) [commonly known as detached-eddy simulation (DES)], where a combination of two-dimensional (2D) and three-dimensional (3D) flow visualization techniques are used to understand the vortex shedding from the main wing and its interaction with the tailplane. Simulation results were compared to the experimental ones and the results with proper orthogonal decomposition (POD) were compared with the HODMD analysis. The main advantage of HODMD resides in its identification of the main physical phenomena and the most relevant instabilities that lead the fluid dynamics. New flow control strategies can be defined when the underlying physics and the flow dynamics are known. Moreover, HODMD is robust in noisy and turbulent databases using less data than fast Fourier transform (FFT), which gives potential for future flow control applications, focused on improving the aircraft’s efficiency.
TL;DR: In this article , the authors investigated the characteristics of unsteady boundary-layer transition on a small-amplitude pitching NACA0012 airfoil using the γ−Reθt¯−Ar transition model.
Abstract: The characteristics of unsteady boundary-layer transition on a small-amplitude pitching NACA0012 airfoil are investigated using the γ−Reθt¯−Ar transition model, which consists of the γ−Reθt¯ transition model and the roughness amplification factor (Ar) transport equation. The present transition model is validated by three roughness surface cases, including a zero pressure gradient flat plate, the NACA0012 airfoil, and NREL-S814 airfoil with different roughness surface. The numerical results for these cases are in agreement with experimental data. Three pitching NACA0012 airfoils with smooth surface, fully distributed roughness surface, and roughness leading edge are simulated by the present model. The impact of reduced frequencies ranging from 0.019 to 0.301 is also taken into consideration. The results show that as the reduced frequency increases, the transition location moves downstream in the upstroke and upstream in the downstroke. With the influence of distributed roughness, the transition moves upstream and the time delay of the transition location is decreased. Moreover, the roughness leading edge enhances the asymmetry of the propagation speed and makes it more sensitive to the reduced frequency.
TL;DR: In this article , an overset grid was used to simulate the active flap control (AFC) airfoil flow field with the artificial vortex interaction, and the noise characteristics were obtained from an acoustic analogy method based on the Farassat 1A (F1A) equation.
Abstract: Blade-vortex interaction (BVI) noise is a significant source of rotor noise. In recent years, active flap control (AFC) has been used successfully to control BVI by adding a trailing edge flap to the blade. However, due to the rotor’s complex shape and motion in AFC, the accurate simulation of the motion and unsteady flow field is challenging. Therefore, studies of noise control by AFC have mostly focused on experimental methods. Few numerical simulations were conducted on the noise reduction mechanism. In order to understand the noise reduction mechanism of the AFC clearly, this paper establishes a computational fluid dynamics (CFD) method based on an overset grid and tries to simulate the AFC airfoil flow field with the artificial vortex interaction. The noise characteristics are obtained from an acoustic analogy method based on the Farassat 1A (F1A) equation. By parameter analysis study and by testing the airfoil load and vertical interference distance, the results show that the proposed active control method exactly reduces the airfoil-vortex interaction noise. A maximum noise reduction of 1.56 dB is observed, and the most critical control parameter is the deflection phase of the trailing edge. When the vortex core passes over the airfoil, the load fluctuation and the interaction noise can be reduced by an upward deflection of the trailing edge. The flapping of the trailing edge significantly changes the vortex core’s path, which can further control the downstream airfoil-vortex interaction and achieve noise reduction.
TL;DR: In this article , a one-equation Reynolds-averaged Navier-Stokes (RANS) closure model has been established for bypass transition and laminar separation bubble (LSB)-induced transition.
Abstract: A one-equation Reynolds-averaged Navier-Stokes (RANS) closure model has been established for bypass transition and laminar separation bubble (LSB)–induced transition. A new local indicator is proposed to describe the influence of turbulence intensities and pressure gradients, which makes the model Galilean invariant. Based on this new indicator, a novel and efficient transition criterion is formulated. For LSB-induced transition, an empirical correlation is developed to modify the intermittency factor and control the size of separation bubbles. Several flow cases, including flat plates with various pressure gradients, flat plates with LSBs, semicircular leading-edge flat plates, National Advisory Committee for Aeronautics (NACA) 0018 airfoil, and SD7003 airfoil, are employed for the model verification. The predictions show good agreement with the experimental data and large-eddy simulation data for different inlet conditions, which indicates the increment of free-stream turbulence intensity leads to the reduction of the size of laminar separation bubbles.
TL;DR: In this article, active flap control has been used to control BVI by adding a trailing edge fusing with active flapping control (AFC) on the rear of the rotor.
Abstract: Blade-vortex interaction (BVI) noise is a significant source of rotor noise. In recent years, active flap control (AFC) has been used successfully to control BVI by adding a trailing edge f...
TL;DR: In this article , the effects of blade surface blowing on BVI noise reduction were analyzed using the improved fifth-order weighted essentially nonoscillatory (WENO-Z) scheme and high-resolution grid system.
Abstract: Reducing rotor blade–vortex interaction (BVI) noise is a major challenge in rotorcraft research. This paper presents a high-resolution numerical study of the effects of blade surface blowing on BVI noise reduction. Using the improved fifth-order weighted essentially non-oscillatory (WENO-Z) scheme and high-resolution grid system, BVI noise is accurately predicted in the nonblowing baseline case. Four slot locations are examined to study the effects of jet slot location on the control of BVI noise. Additionally, the parametric effects of jet velocity and jet slot area are analyzed. Blowing near the trailing edge on the upper surface is effective for weakening BVI. The optimal jet velocity for reducing BVI noise is 20% of the rotor tip speed, which is 45.2 m/s in the case study. Compared with the baseline case, the sound pressure level is reduced by 3.6 dB. By adjusting the jet slot area, surface blowing can effectively reduce the rotor BVI noise by over 3 dB with minimal thrust penalties.
TL;DR: In this article, the authors investigated the effects of projectile shape on the ballistic performance of a single-stage UAV using a honeycomb-core sandwich structure as orbital debris shielding in unmanned satellites.
Abstract: Honeycomb-core sandwich structures are commonly utilized as orbital debris shielding in unmanned satellites. This study investigated the effects of projectile shape on the ballistic perform...
TL;DR: In this paper , a numerical modeling technique based on the numerical solution of the Navier-Stokes equations is proposed to predict the level of near-field pressure pulsations of a near-future prototype supersonic business aircraft.
Abstract: The paper considers practical aspects of mathematical modeling in predictions of the level of near-field pressure pulsations of a near-future prototype supersonic business aircraft. A numerical modeling technique based on the numerical solution of the Navier-Stokes equations is proposed. The method is verified by near-field simulations of the NASA C608 supersonic low-boom demonstrator. We consider a supersonic flight with M=1.4 at a flight altitude of 16,215 m. Good convergence of our predictions with experimental data and results of other researchers is shown. Near-field sonic-boom simulations of the prototype supersonic business aircraft are used to illustrate how the method can be applied in practice for building a second-generation supersonic passenger aircraft. Two aerodynamic configurations of the aircraft are considered: no-tail and canard no-tail. The canard no-tail configuration in the as-is aircraft dimension and design was found to have no advantages over the no-tail configuration in the level of its near-field pressure pulsations because of its nonoptimality. Further recommendations for solving the near-field sonic-boom minimization problem are related to the construction of a comprehensive mathematical model enabling coupled simulations due to smooth integration of a parametrized aircraft geometry, an aerodynamic solver, and an optimizer.
TL;DR: In this paper , a robust adaptive predefined-time control scheme for spacecraft rendezvous maneuvers with the consideration of input saturation and external disturbances is proposed, where a constructive performance function is utilized to impose time-varying constraints on system errors.
Abstract: This paper proposes a robust adaptive predefined-time control scheme for spacecraft rendezvous maneuvers with the consideration of input saturation and external disturbances. To ensure the rendezvous maneuver completing within a predefined time, a constructive performance function is utilized to impose time-varying constraints on system errors. Subsequently, a nonlinear mapping method is employed to transform the constrained problem into an unconstrained one, thus simplifying the design process significantly. Then, two compensation signals are introduced by the feat of an auxiliary system to optimize the steady-state performance of the system. With the combination of backstepping design and compensating signals, the input saturation constraint will be dealt with properly. All of the closed-loop signals are proved to be bounded under the proposed controller. Finally, simulation results demonstrate the validity of the proposed control scheme.
TL;DR: In this paper, a modified optimization criterion was proposed for piezoelectric actuator placement in connection with active vibration control, considering the torsion of the actuator.
Abstract: The optimization of piezoelectric actuator placement has been widely investigated in connection with active vibration control. In this paper, a modified optimization criterion considering t...
TL;DR: In this paper , a modified optimization criterion was proposed for piezoelectric actuator placement in connection with active vibration control, considering the effect of active vibration on actuator performance.
Abstract: AbstractThe optimization of piezoelectric actuator placement has been widely investigated in connection with active vibration control. In this paper, a modified optimization criterion considering t...
TL;DR: In this article , a method of downrange estimation based on improved powered explicit guidance (PEG) focusing on the existing throttleable engine was proposed for future lunar and planetary campaigns with pinpoint landings.
Abstract: Onboard computation of a fuel-optimal steering law is a pivotal technology for future lunar and planetary campaigns with pinpoint landings. This paper proposes a method of downrange estimation based on improved powered explicit guidance (PEG) focusing on the existing throttleable engine. The main contribution includes two aspects. First, the conventional PEG algorithm is improved to enforce prediction accuracy. The prediction of lander cutoff state can be used to estimate downrange position, and thus, the thrust switching time is corrected to recalculate optimal steering law. Second, in consideration of the thrust identification error and navigation uncertainty, the thrust switching condition triggered by the state of the lander instead of time is established. The thrust is switched depending on estimated downrange feedback, and thus, a pinpoint landing with near-optimal fuel is achieved. The effectiveness of the proposed algorithm are demonstrated through Monte Carlo simulations in the presence of thrust deviation and navigation error.
TL;DR: This paper addresses the maintenance of a halo orbit around the L1 point of the Sun-Earth system in a circular restricted three-body problem and a trajectory tracking problem to this effect.
Abstract: This paper addresses the maintenance of a halo orbit around the L1 point of the Sun-Earth system in a circular restricted three-body problem. To this effect, a trajectory tracking problem i...
TL;DR: In this article , a tethered-Coulomb formation (TCF) is proposed that consists of a space tug and a cluster of charged debris connected by elastic massless tethers.
Abstract: In order to reduce the population of space debris in geosynchronous orbit, a tethered-Coulomb formation (TCF) is proposed that consists of a space tug and a cluster of charged debris connected by elastic massless tethers. The charged debris introduces repulsive coulomb forces to avoid collisions among the pieces of debris. In this way, the system is able to maintain a stable configuration when proper system parameters are given. To determine this relationship, a dynamics model of the formation was derived by using Lagrange’s equation. Then, precise and approximate equilibrium solutions of the debris item charges and tether lengths were derived analytically according to the different number of debris items in pyramid configurations of the TCF. Based on the analytical results, pyramid and double-pyramid TCF configurations were studied via numerical simulations. The results showed that oscillations of the debris had little impact on the motion of the tug. When designing a double-pyramid TCF system, two clusters of debris with large relative positions in different phases would show good performance in a deorbit mission.