Aircraft Engineering and Aerospace Technology最新文献

Purpose

Composite materials have revolutionized the aerospace industry by offering superior structural qualities over traditional elements. This study aims to focus on the development and testing of bamboo natural fiber-based composites enhanced with SiO₂ nanoparticles.

Design/methodology/approach

The investigation involved fabricating specimens with varying nanoparticle compositions (0, 10 and 20%) and conducting tensile, flexural, impact and fracture toughness tests. Results indicated significant improvements in mechanical properties with the addition of nanoparticles, particularly at a 10% composition level.

Findings

This study underscores the potential of natural fiber composites, highlighting their environmental friendliness, cost-effectiveness and improved structural properties when reinforced with nanoparticles. The findings suggest an optimal ratio for nanoparticle integration, emphasizing the critical role of precise mixing proportions in achieving superior composite performance.

Originality/value

The tensile strength, flexural strength, impact resistance and fracture toughness exhibited notable enhancements compared with the 0 and 20% nanoparticle compositions. The 10% composition showed the most promising outcomes, showcasing increased strength across all parameters.

Purpose

This study investigates the impact of financial health and corporate governance on aviation safety, aiming to fill a critical gap in existing research. The purpose of this study is to identify how these factors influence the safety records of airlines and provide insights for regulators, airlines and stakeholders to enhance aviation safety.

Design/methodology/approach

Using a comprehensive international sample spanning 1950–2009 and later, this empirical analysis draws on diverse databases. The authors examine 372 airlines across 70 countries from 1990 to 2016. The research uses statistical models to analyze the relationship between financial indicators, corporate governance quality and aviation safety, addressing limitations of prior single-country studies.

Findings

The findings reveal a significant inverse relationship between financial health and accident propensity, with profitable airlines exhibiting lower accident rates. Additionally, airlines with higher corporate governance quality, characterized by qualified directors and stable leadership, experience fewer accidents. The study identifies key factors such as pilot errors, mechanical failures and adverse weather, contributing to approximately 75% of accidents, emphasizing the importance of organizational control.

Practical implications

This research has crucial implications for aviation safety policies and practices. Regulators and international organizations, such as International Civil Aviation Organization and International Air Transport Association, should allocate resources to supervise financially vulnerable airlines and those with lower governance quality. Governments might consider incentivizing safety practices through tax deductibility for relevant expenses. Shareholders are encouraged to prioritize qualified, younger and less busy directors, recognizing their impact on safety performance.

Originality/value

This study contributes to existing literature by addressing methodological biases and offering a comprehensive international perspective. The identification of a link between financial health, corporate governance and accident rates in the aviation industry provides valuable insights. The research informs policymakers, regulators and industry stakeholders on effective strategies to improve safety by considering financial and governance factors under their control.

Purpose

The aim of this study is to determine the fracture behavior of wool felt and fabric based epoxy composites and their responses to electromagnetic waves.

Design/methodology/approach

Notched and unnotched tensile tests of composites made of wool only and hybridized with a glass fiber layer were carried out, and fracture behavior and toughness at macro scale were determined. They were exposed to electromagnetic waves between 8 and 18 GHz frequencies using two horn antennas.

Findings

The keratin and lignin layer on the surface of the wool felt caused lower values to be obtained compared to the mechanical values given by pure epoxy. However, the use of wool felt in the symmetry layer of the laminated composite material provided higher mechanical values than the composite with glass fiber in the symmetry layer due to the mechanical interlocking it created. The use of wool in fabric form resulted in an increase in the modulus of elasticity, but no change in fracture toughness was observed. As a result of the electromagnetic analysis, it was also seen in the electromagnetic analysis that the transmittance of the materials was high, and the reflectance was low throughout the applied frequency range. Hence, it was concluded that all of the manufactured materials could be used as radome material over a wide band.

Practical implications

Sheep wool is an easy-to-supply and low-cost material. In this paper, it is presented that sheep wool can be evaluated as a biocomposite material and used for radome applications.

Originality/value

The combined evaluation of felt and fabric forms of a natural and inexpensive reinforcing element such as sheep wool and the combined evaluation of fracture mechanics and electromagnetic absorption properties will contribute to the evaluation of biocomposites in aviation.

Purpose

This paper aims to propose a novel control scheme and offer a control parameter optimizer to achieve better automatic carrier landing. Carrier landing is a challenging work because of the severe sea conditions, high demand for accuracy and non-linearity and maneuvering coupling of the aircraft. Consequently, the automatic carrier landing system raises the need for a control scheme that combines high robustness, rapidity and accuracy. In addition, to exploit the capability of the proposed control scheme and alleviate the difficulty of manual parameter tuning, a control parameter optimizer is constructed.

Design/methodology/approach

A novel reference model is constructed by considering the desired state and the actual state as constrained generalized relative motion, which works as a virtual terminal spring-damper system. An improved particle swarm optimization algorithm with dynamic boundary adjustment and Pareto set analysis is introduced to optimize the control parameters.

Findings

The control parameter optimizer makes it efficient and effective to obtain well-tuned control parameters. Furthermore, the proposed control scheme with the optimized parameters can achieve safe carrier landings under various severe sea conditions.

Originality/value

The proposed control scheme shows stronger robustness, accuracy and rapidity than sliding-mode control and Proportion-integration-differentiation (PID). Also, the small number and efficiency of control parameters make this paper realize the first simultaneous optimization of all control parameters in the field of flight control.

Purpose

This study aims to examine the moderating role of formalization in the relationship between human resources (HR) practices and work engagement (WE) in aviation industry employees. The research revealed the moderator role of formalization, which is still one of the most critical components for aviation industry workers.

Design/methodology/approach

In the study, the authors used the survey method. In this explanatory and cross-sectional study, the authors examined a data set collected from aviation industry employees (n = 226) in Turkey using the partial least squares (PLS) method and tried to moderate the formalization. The authors analyzed the moderator role of formalization in the relationship between HR practices and WE with SmartPLS 3.0 and HAYES Process Macro.

Findings

The results of the study explain the effect of HR practices on WE in the context of social exchange theory through formalization. Findings show that formalization is an essential factor in HR practices’ resulting in higher WE.

Research limitations/implications

The study is cross-sectional. Research participants participated in the study voluntarily. This situation, in turn, may lead to a social desirability bias in participants' self-reported responses. To avoid this, the authors have prepared a standardized measurement tool. Again, since the authors do not request the names and institutions of the participants, confidentiality and anonymity are provided.

Practical implications

Research findings offer implications for companies and employees in developing economies, especially in the aviation sector. It refers to the necessity for companies aiming for a sustainable strategic position in the competitive aviation sector to attach importance to HR practices that will enable them to see their employees as a competitive advantage. In addition, the results emphasize the need for aviation industry companies to adopt an approach that considers both practices that can increase WE and formalization procedures that can affect employee behavior.

Originality/value

This research provides a comprehensive understanding to examine the interrelationships between HR, formalization and WE in the context of the mechanism of social change in the context of aviation industry workers. To the best of the authors’ knowledge, no other researcher has holistically addressed these links in general, particularly in a developing country. The findings significantly enrich the literature on HR practices and WE, particularly in the context of a developing country.

Purpose

Aero-engine exhaust plume length can be more than the aircraft length, making it easier to detect and track by infrared seeker. Aim of this study is to analyze the effect of free stream Mach number (M_∞) on length of potential core of plume. Also, change in infrared (IR) signature of plume and aircraft surface with variation in elevation angle (θ) is examined.

Design/methodology/approach

Convergent divergent (CD) nozzle is located outside the rear fuselage of the aircraft. A two dimensional axisymmetric computational fluid dynamics (CFD) study was carried out to study effect of M_∞ on potential core. The CFD data with aircraft and plume was then used for IR signature analysis. The sensor position is changed with respect to aircraft from directly bottom towards frontal section of aircraft. The IR signature is studied in mid wave IR (MWIR) and long wave IR (LWIR) band.

Findings

The potential plume core length and width increases as M_∞ increases. At higher altitudes, the potential core length increases for a fixed M_∞. The plume emits radiation in the MWIR band, whereas the aerodynamically heated aircraft surface emits IR in the LWIR band. The IR signature in the MWIR band continuously decreases as the sensor position changes from directly bottom towards frontal. In the LWIR band the IR signature initially decreases as the sensor moves from the directly bottom to the frontal, as the sensor begins to see the wing leading edges and nose cone, the IR signature in the LWIR band slightly increases.

Originality/value

The novelty of this study comes from the data reported on the effect of free stream Mach number on the potential plume core and variation of the overall IR signature of aircraft with change in elevation angle from directly below towards frontal section of aircraft.

Purpose

This study aims to learn the dynamic radar cross-section (RCS) of a deflection air brake.

Design/methodology/approach

The aircraft model with delta wing, V-shaped tail and blended wing body is designed, and high-precision unstructured grid technology is used to deal with the surface of air brake and fuselage. The calculation method based on multiple tracking and dynamic scattering is presented to calculate RCS.

Findings

The fuselage has a low scattering level, and the opening air brake will bring obvious dynamic RCS effects to itself and the whole machine. The average indicator of air brake RCS can be lower than –0.6 dBm² under the tail azimuth, while that of forward and lateral direction is lower. The mean RCS of fuselage is obviously higher than that of air brake, while the deflected air brake and its cabin can still provide strong scattering sources at some azimuths. When the air brake is opening, the change amplitude of the aircraft forward RCS can exceed 19.81 dBm².

Practical implications

This research has practical significance for the dynamic electromagnetic scattering analysis and stealth design of the air brake.

Originality/value

The calculation method for aircraft RCS considering air brake dynamic deflection has been established.

Purpose

The purpose of this paper is to improve autonomous flight performance of a fixed-wing unmanned aerial vehicle (UAV) via simultaneous morphing wingtip and control system design conducted with optimization, computational fluid dynamics (CFD) and machine learning approaches.

Design/methodology/approach

The main wing of the UAV is redesigned with morphing wingtips capable of dihedral angle alteration by means of folding. Aircraft dynamic model is derived as equations depending only on wingtip dihedral angle via Nonlinear Least Squares regression machine learning algorithm. Data for the regression analyses are obtained by numerical (i.e. CFD) and analytical approaches. Simultaneous perturbation stochastic approximation (SPSA) is incorporated into the design process to determine the optimal wingtip dihedral angle and proportional-integral-derivative (PID) coefficients of the control system that maximizes autonomous flight performance. The performance is defined in terms of trajectory tracking quality parameters of rise time, settling time and overshoot. Obtained optimal design parameters are applied in flight simulations to test both longitudinal and lateral reference trajectory tracking.

Findings

Longitudinal and lateral autonomous flight performances of the UAV are improved by redesigning the main wing with morphing wingtips and simultaneous estimation of PID coefficients and wingtip dihedral angle with SPSA optimization.

Originality/value

This paper originally discusses the simultaneous design of innovative morphing wingtip and UAV flight control system for autonomous flight performance improvement. The proposed simultaneous design idea is conducted with the SPSA optimization and a machine learning algorithm as a novel approach.

Purpose

The purpose of this paper is to solve the challenging problem of automatic carrier landing with the presence of environmental disturbances. Therefore, a global fast terminal sliding mode control (GFTSMC) method is proposed for automatic carrier landing system (ACLS) to achieve safe carrier landing control.

Design/methodology/approach

First, the framework of ACLS is established, which includes flight glide path model, guidance model, approach power compensation system and flight controller model. Subsequently, the carrier deck motion model and carrier air-wake model are presented to simulate the environmental disturbances. Then, the detailed design steps of GFTSMC are provided. The stability analysis of the controller is proved by Lyapunov theorems and LaSalle’s invariance principle. Furthermore, the arrival time analysis is carried out, which proves the controller has fixed time convergence ability.

Findings

The numerical simulations are conducted. The simulation results reveal that the proposed method can guarantee a finite convergence time and safe carrier landing under various conditions. And the superiority of the proposed method is further demonstrated by comparative simulations and Monte Carlo tests.

Originality/value

The GFTSMC method proposed in this paper can achieve precise and safe carrier landing with environmental disturbances, which has important referential significance to the improvement of ACLS controller designs.