Wing Vibration Research Articles

Experimental study on thermally induced vibration of flexible solar cell wing simulator

Abstract With the development of large spacecraft and satellite payloads, the power supply required is increasing, especially in space solar power stations, and the large flexible solar wing is an inevitable trend in the future. Due to their light weight and large area, flexible solar wings may face thermally induced vibration during orbit operation, which will lead to the degradation of spacecraft performance and even structural damage. In this paper, the test method of a flexible solar wing simulator is established, and the thermally induced vibration test of a flexible solar cell wing simulator is carried out. And vibration amplitude value is 25 and 9 microns with a frequency 0.56Hz.The characteristic of thermally induced vibration of flexible solar cell wing is given, which provides a basis for its thermally induced vibration suppression.

Comparation of pheromone-binding proteins 1 and 2 of Spodoptera frugiperda in perceiving the three sex pheromone components Z9-14:Ac, Z7-12: Ac and Z11-16: Ac

Pheromone-binding proteins (PBPs) are mainly responsible for binding and transporting hydrophobic pheromone molecules across the aqueous sensilla lymph to the receptor proteins. The preference of each PBP is believed to be different for each pheromone component within a single species. Significantly higher expression level of PBP1 and PBP2 in the male antennae of Spodoptera frugiperda suggesting that SfruPBP1 and SfruPBP2 might play important roles in pheromone perception. However, the preference of these two PBP to the three main pheromone components Z9-14: Ac, Z7-12: Ac and Z11-16: Ac have not been determined. In this study, a fluorescence competitive binding assay revealed that the binding intensities of SfruPBP1 and SfruPBP2 to Z9-14: Ac or Z7-12: Ac was comparable. We then used the CRISPR/Cas9 system to individually or simultaneously knock out PBP1 and PBP2 in S.frugiperda. The result of courtship behavior indicated that SfruPBP1 and SfruPBP2 were indispensable and played equal roles in perceiving the pheromones Z9-14: Ac and Z7-12: Ac for orientation, wing vibration, and hair-pencil display. Compared with Z9-14:Ac and Z7-12: Ac, Z11-16: Ac showed higher or medium binding intensities with SfruPBP1 and SfruPBP2 but played a minor role in inducing the wing vibration behavior. The results of this study are valuable for elucidating the mechanisms involved in sex pheromone perception and may facilitate the development of PBP-targeted pest control techniques.

Nonlinear metamaterial enabled aeroelastic vibration reduction of a supersonic cantilever wing plate

The violent vibration of supersonic wings threatens aircraft safety. This paper proposes the strongly nonlinear acoustic metamaterial (NAM) method to mitigate aeroelastic vibration in supersonic wing plates. We employ the cantilever plate to simulate the practical behavior of a wing. An aeroelastic vibration model of the NAM cantilever plate is established based on the mode superposition method and a modified third-order piston theory. The aerodynamic properties are systematically studied using both the timedomain integration and frequency-domain harmonic balance methods. While presenting the flutter and post-flutter behaviors of the NAM wing, we emphasize more on the pre-flutter broadband vibration that is prevalent in aircraft. The results show that the NAM method can reduce the low-frequency and broadband pre-flutter steady vibration by 50%–90%, while the post-flutter vibration is reduced by over 95%, and the critical flutter velocity is also slightly delayed. As clarified, the significant reduction arises from the bandgap, chaotic band, and nonlinear resonances of the NAM plate. The reduction effect is robust across a broad range of parameters, with optimal performance achieved with only 10% attached mass. This work offers a novel approach for reducing aeroelastic vibration in aircraft, and it expands the study of nonlinear acoustic/elastic metamaterials.

Aircraft deicing based on large vibration of wings

Since aircraft icing will decrease the ability of aircraft to generate lift, it is significant to consider the aircraft deicing problem. The paper presents an aircraft deicing method based on the cracking of the ice layer caused by the large deformations of wings. To describe the deformation of wings, the absolute coordinate-based formulation is used. The aircraft with high aspect ratio wings is simplified as a hub-beam system. Such a rigid-flexible system with the fast rotation speed of hub and the large deformation of the beam is modeled using absolute coordinate-based formulation accurately. The maneuver of the rigid body will lead to the large deformation of wings to do the de-icing. Numerical examples are presented to reveal that the maximum tensile strength on the wing surface with sinusoidal control torques with some amplitudes and frequencies is larger than the ice’s tensile strength. Hence, the proposed de-icing method based on the aircraft maneuvering is potential.

Active control vibrations of aircraft wings under dynamic loading: Introducing PSO-GWO algorithm to predict dynamical information

This study presents an innovative approach to mitigate vibrations induced by external shock on composite structures through the application of an intelligent controller. Leveraging the first-order shear deformation panel theory, a sophisticated controller scheme is developed, integrating methodologies such as the differential quadrature approach and Laplace transform. Furthermore, deep neural network (DNN) and support vector regression (SVR) techniques are employed to enhance prediction accuracy and control efficiency. Additionally, two optimized hybrid models are proposed, incorporating Particle Swarm Optimization (PSO) and Grey Wolf Optimizer (GWO) algorithms, to further refine the controller's performance. The proposed methodology aims to address the challenges associated with vibrations in composite structures by providing a comprehensive and adaptive control solution. By utilizing advanced optimization algorithms and machine learning techniques, the controller can effectively adapt to dynamic changes in external shock conditions, thereby minimizing vibrations and ensuring structural integrity. The integration of ANN and SVR enhances the controller's predictive capabilities, enabling it to anticipate and respond to varying shock scenarios with precision. Through theoretical analysis and numerical simulations, the effectiveness of the proposed intelligent controller is demonstrated in reducing vibrations and enhancing the structural stability of composite systems. The optimized hybrid models, employing PSO and GWO algorithms, further improve the controller's performance by fine-tuning its parameters for optimal control efficiency. Overall, this research contributes to the development of robust control strategies for mitigating vibrations in composite structures subjected to external shock, with potential applications in aerospace, automotive, and civil engineering industries.

Wake interference effects on flow-induced vibration of flexible membrane wings

This work investigates the effect of wake interference on the nonlinear coupled dynamics and aerodynamic performance of flexible membrane wings at a moderate Reynolds number. A high-fidelity computational aeroelastic framework is employed to simulate the flow-induced vibration of flexible membrane wings in response to unsteady vortex wake flows produced by an upstream stationary circular cylinder. The coupled dynamics of the downstream membrane are investigated at different gap ratios, aeroelastic numbers, and offset distances. The variations in flow features, membrane responses, and frequency characteristics are analyzed to understand the wake interference effect on membrane aeroelasticity. The results indicate that the aerodynamic performance and flight stability of the downstream membrane are degraded under the wake interference effect. Four distinct flow regimes are classified for the cylinder–membrane configuration, namely (i) single body flow, (ii) co-shedding I, (iii) co-shedding II, and (iv) detached vortex-dominated vibration, respectively. The mode transition is found to build new frequency synchronization between the flexible membrane and its own surrounding flows, or the wake flows of the cylinder, to adjust the aerodynamic performance and membrane vibration. This study sheds new light on membrane aeroelasticity in response to wake flows and enhances understanding of the fluid–membrane coupling mechanism. These findings can facilitate the development of next-generation bio-inspired drones that have high flight efficiency and robust flight stability in gusty flows.

WITHDRAWN: Visualized neural network-based vibration control for pigeon-like flexible flapping wings

This study investigates pigeon-like flexible flapping wings, which are known for their low energy consumption, high flexibility, and lightweight design. However, such flexible flapping wing systems are prone to deformation and vibration during flight, leading to performance degradation. It is thus necessary to design a control method to effectively manage the vibration of flexible wings. This paper proposes an improved rigid finite element method (IRFE) to develop a dynamic visualization model of flexible flapping wings. Subsequently, an adaptive vibration controller was designed based on non-singular terminal sliding mode (NTSM) control and fuzzy neural network (FNN) in order to effectively solve the problems of system uncertainty and actuator failure. With the proposed control, stability of the closed loop system is achieved in the context of Lyapunov’s stability theory. At last, a joint simulation using MapleSim and MATLAB/Simulink was conducted to verify the effectiveness and robustness of the proposed controller in terms of trajectory tracking and vibration suppression.The obtained results have demonstrated great practical value of the proposed method in both military (low-altitude reconnaissance, urban operations, and accurate delivery, etc.) and civil (field research, monitoring, and relief for disasters, etc.) applications.

Flexible calorimetric flow sensor with unprecedented sensitivity and directional resolution for multiple flight parameter detection

The accurate perception of multiple flight parameters, such as the angle of attack, angle of sideslip, and airflow velocity, is essential for the flight control of micro air vehicles, which conventionally rely on arrays of pressure or airflow velocity sensors. Here, we present the estimation of multiple flight parameters using a single flexible calorimetric flow sensor featuring a sophisticated structural design with a suspended array of highly sensitive vanadium oxide thermistors. The proposed sensor achieves an unprecedented velocity resolution of 0.11 mm·s−1 and angular resolution of 0.1°. By attaching the sensor to a wing model, the angles of attack and slip were estimated simultaneously. The triaxial flight velocities and wing vibrations can also be estimated by sensing the relative airflow velocity due to its high sensitivity and fast response. Overall, the proposed sensor has many promising applications in weak airflow sensing and flight control of micro air vehicles.

Effectively reduce transient vibration of 2D wing with bi-stable metamaterial

Unsteady time-varying flow during flight may causes transient vibrations of wings, limiting aircraft safety and requiring effective suppression methods. Nonlinear acoustic metamaterials have recently attracted extensive attention owing to their superior capability for low-frequency and broadband vibration suppression. However, most existing nonlinear metamaterials consist of mono-stable nonlinear resonators, whose transient vibration reduction capability requires significant improvement. This paper proposes a 2D metamaterial wing model consisting of bi-stable nonlinear resonators. Based on CFD simulation, we establish an equivalent model surrounded by a fluid-like medium and systematically investigate its transient dynamics and energy dissipation. Results indicate that the bi-stable metamaterial can quickly dissipate the transient vibrations of the wing with an efficiency much higher than the linear and mono-stable nonlinear counterparts. An energy dissipation rate of over 75 % is achievable with an added mass ratio of 4 %–8 %, while the energy dissipation rate of the linear counterpart is below 60 %. The subharmonic nonlinear beatings and subharmonic resonance capture, such as 1:2 or 2:3 resonances between multiple modes, are essential mechanisms for the improvement. The reduction is robust to varying amplitudes and the distance between the two stable states. These findings provide new ways to reduce the fluid-structure interaction transient vibrations of structures.

Wing mechanics and acoustic communication of a new genus of sylvan katydid (Orthoptera: Tettigoniidae: Pseudophyllinae) from the Central Cordillera cloud forest of Colombia.

Stridulation is used by male katydids to produce sound via the rubbing together of their specialised forewings, either by sustained or interrupted sweeps of the file producing different tones and call structures. There are many species of Orthoptera that remain undescribed and their acoustic signals are unknown. This study aims to measure and quantify the mechanics of wing vibration, sound production and acoustic properties of the hearing system in a new genus of Pseudophyllinae with taxonomic descriptions of two new species. The calling behaviour and wing mechanics of males were measured using micro-scanning laser Doppler vibrometry, microscopy, and ultrasound sensitive equipment. The resonant properties of the acoustic pinnae of the ears were obtained via μ-CT scanning and 3D printed experimentation, and numerical modelling was used to validate the results. Analysis of sound recordings and wing vibrations revealed that the stridulatory areas of the right tegmen exhibit relatively narrow frequency responses and produce narrowband calls between 12 and 20 kHz. As in most Pseudophyllinae, only the right mirror is activated for sound production. The acoustic pinnae of all species were found to provide a broadband increased acoustic gain from ~40-120 kHz by up to 25 dB, peaking at almost 90 kHz which coincides with the echolocation frequency of sympatric bats. The new genus, named Satizabalus n. gen., is here derived as a new polytypic genus from the existing genus Gnathoclita, based on morphological and acoustic evidence from one described (S. sodalis n. comb.) and two new species (S. jorgevargasi n. sp. and S. hauca n. sp.). Unlike most Tettigoniidae, Satizabalus exhibits a particular form of sexual dimorphism whereby the heads and mandibles of the males are greatly enlarged compared to the females. We suggest that Satizabalus is related to the genus Trichotettix, also found in cloud forests in Colombia, and not to Gnathoclita.

Robust control of gust-induced vibration of highly flexible aircraft

This paper mainly addresses the gust suppression and alleviation of highly flexible aircraft using the model predictive controller (MPC) based on linear parameter-varying (LPV) models. The dynamic behavior of highly flexible aircraft is modeled by a coupled nonlinear aeroelastic and flight dynamic formulation. Conventional trailing-edge flaps along the main wings and tails are deployed to provide the required loads for the wing vibration control and/or longitudinal flight attitude control of the slender vehicle. The coupled dynamic equations are performed with linearization and model reduction about a series of nonlinear equilibria to derive reduced-order LPV models. This work considers two quantities as the scheduling parameters in building the LPV models: the gust-induced angle of attack and the modal magnitude of wing deformation. With the reduced-order LPV model, MPC is designed to minimize the wing vibration and rigid-body motions excited by the time-domain Dryden gust perturbation. The proposed LPV modeling is capable of describing large wing deformations, and the LPV-MPC innovatively previews the scheduling parameter and gust disturbance in the prediction horizon. The closed-loop flight responses of a highly flexible aircraft with gust disturbance are presented in the numerical studies, which demonstrate the effectiveness of controlling coupled vibrations and rigid-body dynamics of such slender vehicles.

Utilization of Mating Behavior as a Parameter to Understand Adaptive Response in <i>Drosophila melanogaster</i> using Ethyl Methanesulfonate and Methyl Methanesulfonate

Monofunctional alkylating agents, Ethyl Methanesulfonate (EMS) and Methyl Methanesulfonate (MMS) were used to understand adaptive response utilising mating behaviour as a parameter in D. melanogaster. Selected conditioning and challenging doses of EMS (0.5mM and 15mM) or MMS (0.1mM and 3mM) by larval feeding were tested employing different combinations of crosses. The results have revealed that both EMS and MMS affected courtship elements significantly in different combinations of crosses. Nonetheless, significant increases in orientation, tapping, wing vibration and licking were observed when both males and females were treated with a challenging dose of MMS compared to EMS (p<0.05). On par with this, were also the results of female rejection elements in both the tested chemicals. When conditioning and challenging doses were given after 2 hours of time lag between them to 48±4h or 72±4h aged larvae of D. melanogaster, the results showed that male and female courtship elements significantly reduced compared to the additive effect of respective agents. Similarly, the courtship latency and copulation latency were significantly decreased in contrast to copulation duration which was significantly increased (p<0.05). Thus the results demonstrate the presence of adaptive response in D. melanogaster using courtship elements and the authors opine that mating behaviour can be used as a parameter to analyze adaptive response in D. melanogaster within a short period of time compared to other test procedures.

An Analytical Solution on Vibration Reduction and Shear Force Mitigation of Cantilever Mindlin Plates Using Orthogonal Ribs

Vibration of aircraft wings and the dynamic stress concentration at the clamped edge are important research topics due to concerns on the safety of aircrafts. To have a better understanding of the problem, the free and forced vibration response of a ribbed rectangular cantilever plate representing a section of an aircraft wing is investigated in this study. A new analytical solution is developed for the vibration analysis of rib stiffened cantilever plates using Mindlin plate and Timoshenko beam theories alongside the finite integral transform technique. The one- and two-dimensional integral transforms are applied to the governing equations of beams and plates, respectively, where the coupling force components at the interface between the base plate and the beam(s) can be automatically defined during the integral transform. Eventually, the partial differential equations are transformed into a system of linear algebraic equations in which its derivation is rigorous and easily implemented. Good agreements are found between the results of analytical solution, finite element analysis (FEA) and related literature. The solution is then employed to study the vibration suppression of cantilever plates and the shear force at the clamped edge. It is found that the insertion of a pair of orthogonal ribs in the plate can effectively reduce its vibration. An optimum orthogonal ribbing pattern is obtained using multi-objective particle swarm optimization (MOPSO) algorithm, taking into consideration both the vibration suppression of the plate and the maximum induced shear force at the corners of the clamped edge.

Probing Acoustic Communication during Fly Reproductive Behaviors.

During reproduction, male and female flies use wing vibration to generate different acoustic signals. Males produce a courtship song before copulation that is easily recognized by unilateral wing vibration. In copula, females produce a distinct sound pattern (copulation song) with both wings. Sexual rejection of immature virgins and aggressive encounters between males are also accompanied by sound pulses generated by wing flicks. Fly song has frequency ranges audible to the human ear and can be directly listened to after appropriate amplification. When displayed in an oscillogram, audio recordings can be mapped on wing-movement patterns and thus provide a fast and precise method to sample and quantify motor behaviors with high temporal resolution. After recording different fly sounds, their effect on behavior can be tested in playback experiments.

Design of Flexible Drilling and Milling Tool for Composite Wing Beam of Aircraft

To solve the disadvantages of traditional processing tooling, such as long processing cycle, low production efficiency, and easy deformation during the processing of large-size composite wing beams, a drilling and milling tooling for flexible positioning of composite wing beams of multiple types of aircraft is proposed based on the structural characteristics and manufacturing technology requirements of a certain type of aircraft wing spar combined with flexible tooling design technology. And a modular mobile clamping unit with automatic control is designed. Then the practical problems such as the difficult clamping and positioning of large-size wing beams, the deformation and vibration during processing are solved by the flexible drilling and milling tool. The results of the current design are helpful to improve the processing efficiency and shorten the manufacturing period of the wing beams.

Numerical investigation of power flow input into a fuselage due to jet engine induced wing vibrations

The wings of passenger aircrafts are constantly vibrating due to various loads. There are transient low-frequency vibrations caused by gust loads. But there are also higher-frequency vibrations caused by the vibration load of the jet engines. The higher-frequency stationary vibrations of the wing are partially introduced as a power flow into the fuselage and radiated there as sound, which is then perceived as noise. In this work, which is part of the EU CleanSky2 framework, this chain of effects is being investigated in more detail aiming for the quantification of the vibrational power flow input into the fuselage by utilizing structural intensity. In this paper, numerical investigations are carried out on FEM models of an Airbus A320 wing generated with a parametric model generator. First, the structural components mainly responsible for the power transmission are identified, and second, the magnitude of the power input into the fuselage is determined in dependence of the pylon position along the wing. The engine vibrations are approximated by a custom-developed model. In the further course of the project, these numerical results will be validated by a test campaign. For this purpose, a real wing of an A320 is available as a test structure.

Influence of UAV Jittering on Sensing Performance in ISAC System

The integrated sensing and communication (ISAC) based on unmanned aerial vehicle (UAV) is considered to be an important candidate technology for future wireless communication, which can overcome the problem that the line-of-sight (LoS) path of ground communication in millimeter wave or terahertz band is easily blocked. However, recent studies have shown that due to the change of wind speed, the vibration of wing and other factors, UAV will appear jittering effect, which will seriously affect the communication performance. With the continuous research of ISAC, it is also necessary to explore the impact of UAV jittering on the sensing performance. This paper first proposes the UAV jittering model, then takes the target angle sensing scheme based on time-division wave scanning as an example, and explores the influence of UAV jittering on target sensing. This paper finds that UAV jittering has great influence on the accuracy and resolution of target sensing. Simulation results confirm this conclusion.

On the experimental scaling and power dissipation of violent sloshing flows

Violent and vertical sloshing flows appear when the fuel tanks of aircraft wings are shaken by air gusts or turbulence. The liquid slosh inside of the tank significantly damps the wing vibrations and its behaviour is still not fully understood. In this paper a simplified version of the problem is tackled, presenting the results obtained in an experimental campaign that investigates the scaling effects and the influence of the most relevant non-dimensional numbers of the problem. Single degree of freedom (SDOF) Froude scaled decay tests are devised in order to study the vertical sloshing problem in an aerospace context establishing relations between the slosh induced damping ratio and three of the most relevant non-dimensional numbers, namely the filling level, density ratio and initial amplitude. The experimental results indicate a maximum damping for a 50% fill level and a positive relationship between the damping ratio with the density ratio. The initial amplitude also increases with the damping ratio up until a threshold amplitude after which the damping starts to decrease. A clear explanation of the liquid induced damping ratio behaviour, confirmed for the three selected scales, is given in terms of two magnitudes: the sloshing force intensity and the phase-shift between this force and the tank motion. These two magnitudes are the key elements behind the physical interpretation of the liquid dissipation in the problem.Finally, the power dissipated by the liquid is calculated and correlated with the liquid slosh damping ratio, the sloshing force intensity and the phase-shift. This correlation shows an equivalency of the damping ratio with the dissipated power.

Adaptive Finite-Time Fault-Tolerant Control for Uncertain Flexible Flapping Wings Based on Rigid Finite Element Method

The bionic flapping-wing robotic aircraft is inspired by the flight of birds or insects. This article focuses on the flexible wings of the aircraft, which has great advantages, such as being lightweight, having high flexibility, and offering low energy consumption. However, flexible wings might generate the unexpected deformation and vibration during the flying process. The vibration will degrade the flight performance, even shorten the lifespan of the aircraft. Therefore, designing an effective control method for suppressing vibrations of the flexible wings is significant in practice. The main purpose of this article is to develop an adaptive fault-tolerant control scheme for the flexible wings of the aircraft. Dynamic modeling, control design, and stability verification for the aircraft system are conducted. First, the dynamic model of the flexible flapping-wing aircraft is established by an improved rigid finite element (IRFE) method. Second, a novel adaptive fault-tolerant controller based on the fuzzy neural network (FNN) and nonsingular fast terminal sliding-mode (NFTSM) control scheme are proposed for tracking control and vibration suppression of the flexible wings, while successfully addressing the issues of system uncertainties and actuator failures. Third, the stability of the closed-loop system is analyzed through Lyapunov's direct method. Finally, co-simulations through MapleSim and MATLAB/Simulink are carried out to verify the performance of the proposed controller.

EFFECTS OF ENHANCER DIESEL FUEL AND VIBRATING WINGS SUBSOILER PLOW ON THE PERFORMANCE OF AN AGRICULTURAL TRACTOR

The aim of the study was to investigate the fuel consumption, depth stability ratio, noise, driver seat vibration of agricultural tractors (DSV), and slippage during tractor operation by using a kind of fuel (enhancer and non-enhancer fuel), vibration and non-vibration wings of subsoiler and engine speeds. Three engine speeds that include 1000, 1500 and 2000 rpm were considered. The results indicated significant positive data for all traits under enhancer fuel compared with non-enhancer and studies treatments. The experiment was analyzed as a three-factor factorial experiment using a split-split plot- Randomized Complete Block Design. Duncan's multiple range test used to test for significance. The results showed positive superiority of enhancer fuel in the fuel consumption, depth stability ratio, noise, DSV, and slippage, while achieving a negative increase in DSV, noise, and slippage with wing vibration of subsoiler. However, the DSV for wing vibration of subsoiler remained within European Parliament and Council Directive 2002/44/EC (OJ, 2002) and the measurements previously approved from ISO 2631-5 (2004). Besides, increasing the engine speeds leads to an increase in noise, DSV, and slippage, while at 2000 rpm speed of the engine was recorded as the lowest value of 11.905 L. ha-1 for fuel consumption, respectively. Finally, the results indicate the superiority of enhancer fuel and vibration wings at all engine tractor speeds to register less fuel consumption, DSV and slipping lead to the conclusion that adding enhancer fuel improved the performance of the agricultural tractor.