Journal of Aerospace Technology and Management

The Role of the Government in the Development of the Aircraft Manufacturing Industry in Korea: Implications for Developing Countries

Jimin Yim — 2024-08-12

The aircraft manufacturing industry is critical to national defense and linked to various other industries. This paper explains the development of Korea’s aircraft manufacturing industry and the role of the government. Despite late entrance to the industry, Korea has developed and produced basic and jet trainers since the 1990s. In the meantime, the government has pursued technology sharing, integrated large companies, and provided financial incentives to manufacturers. It has also supported the strengthening of human capital and established a government research institute devoted to the aircraft manufacturing industry. In the early 2020s, Korea began to produce advanced fighter jets using its technologies. Based on Korea’s experience, this research presents policy implications for developing countries. The government must play a critical role in the aircraft manufacturing industry, which is an example of the infant industry argument. In the early stages of development, a developing country may learn advanced technologies through licensed production contracts and by requesting technology transfer when purchasing aircraft. It is necessary for the government to provide appropriate incentives, particularly for R&D activities, human capital development, and a dedicated government research institute in aircraft manufacturing. Moreover, regulating the number of domestic aircraft manufacturers may lead to greater efficiency

Manufacturing in Space: An Operations Management Nightmare

Robert Oliver Walton — 2024-10-25

Operations management (OM) involves the activities related to producing goods by transforming input into output. Operations managers typically organize the design of goods and manage the processes to ensure a quality product. Many of these processes also apply to the future production of goods in space. Space resources are enablers for space travel and life on other bodies, but they must be processed from raw material to a finished good that can be used. Using terrestrial OM processes, we can imagine the procedures and processes needed to operate production plants in space. Some critical issues will be interoperability, sustainability, and high-quality control, but many other OM factors must be considered and explored.

Mathematical Modeling of Operating Process Parameters of a Mixed-flow Turbofan Engine with an Afterburner

Mykola Kulik — 2024-10-25

The article provides a brief analytical review of mathematical models of the working process used to study the parameters and characteristics of a gas turbine engine at all stages of its creation and operation. It is shown that the first-level mathematical model can be used for the estimation of parameters and characteristics under real operating conditions that differ significantly from the calculated ones. A mathematical model of a mixed-flow turbofan engine with an afterburner is proposed in the article; the construction principle and structure of the mathematical model of the engine are given. The model allows solving various problems associated with calculating the performance of a mixed-flow turbofan engine with an afterburner in a wide range of external conditions and engine operating modes.

Proposal of a Matrix to Measure the Perceived Level of Safety in a Terminal Control Area

Paula Bernardes de Oliveira Babinski — 2024-09-27

The airspace is constantly adapting to efficiently absorb the growing traffic demand in the coming years and may therefore present bottlenecks for safety maintenance, especially in the Terminal Control Area (TMA), where the concentration of aircraft causes them to fly closer to each other. This paper presents a matrix of safety parameters to assess the perception of the safety level after modifications to the airspace, using the TMA from the state of São Paulo/Brazil, as an example for validation, following the implementation of the new airspace circulation in 2021. Through theoretical review, it was possible to delimit the study area and link related research to the presented matrix. The results indicated points of divergence among the surveyed stakeholders, such as speed adjustments which resulted in significant improvements for controllers, while for pilots, improvements were seen in traffic flow and waiting times. Overall, there was a positive perception regarding the decrease in workload in complex airspace, which translates into increased operational safety. Finally, areas for improvement were identified for future terminal designs, particularly regarding the need to reduce potential conflicts.

A DFX Attribution Method Applied to Integrated Product Development within the Aerospace Domain

Rogerio Greco Copriva — 2024-09-27

The aerospace industry continually seeks to optimize product development processes to remain competitive. Design for Excellence (DFX) plays a crucial role in meeting customer expectations while aligning with organizational capabilities. However, the diversity of DFX technological areas and methods can make it challenging for companies to select the appropriate ones for each project. Successful DFX application, ensuring projects stay within scope, time, cost, and quality constraints without overburdening the development process, often depends on the engineering team’s experience and the project phase. This work maps DFX technological areas to address the decision-making problem of selecting the most suitable ones for various projects. The objective is to evaluate, from the engineering team’s perspective, whether a general approach can guide project managers in selecting key DFX areas, considering a typical aerospace organization’s project portfolio and specific project phase characteristics. Starting with a literature review of DFX in aerospace, the research includes a survey along with senior product development engineers. Quantitative results are gathered using the Likert scale and analyzed through the analytic hierarchy process (AHP). The paper presents a method to guide the initial selection of DFX areas, aiding project managers and engineers in designing complex products.

Nonlinear Guidance Laws for Anti-tank Guided Missile to Intercept Maneuvering Tank Targets Using Optimal Error Dynamics and Relative Virtual Model

Hai Tran Van — 2024-09-27

This paper introduces a new method for synthesizing guidance laws for anti-tank guided missiles (ATGM) to intercept maneuvering tank targets. It utilizes a nonlinear relative model in the two-dimensional horizontal plane and optimal error dynamics (OED) theory. The nonlinear relative model simplifies the problem of targeting a moving target into attacking a stationary target, making the guidance law synthesis task easier. The selection of OED allows for the design of a guidance command that ensures the zero effort miss (ZEM) error decreases to zero within a finite time, ensuring successful target interception. The paper also introduces an exponential decay weighting function of remaining time-to-go to optimize the distribution of command accelerations throughout the guidance process, thereby reducing initial command requirements and converging acceleration commands towards zero at the end time. The synthesized guidance laws are derived based on the nonlinear relative model and OED without making any small-angle linearization assumptions, allowing them to address various nonlinear scenarios. Numerical simulations illustrate the proposed guidance law’s performance.

Selection of Routing Metrics and Service Channel Characteristics of ad hoc Network for UAV Swarm

Vyacheslav Borodin — 2024-10-04

Swarm technologies for unmanned aerial vehicles (UAV), which represent a qualitatively new level of robotics development, can significantly increase the efficiency of using drones. From the point of view of organizing communications, such a swarm is an ad hoc network, the nodes of which are UAV. A characteristic feature of this network is the frequent change in the network structure due to changes in the position of UAV in space, necessitating the use of dynamic routing protocols when transmitting information within the swarm. This article is devoted to the study of the behavior of a self-organizing radio network, which uses various variants of the algorithm for finding the shortest route distance with reference to the constantly changing network topology. An analysis of the behavior of such a network was carried out using various options for routing metrics: node metrics, characterizing the state of network nodes, and channel metrics, characterizing the state of communication channels between nodes. Particular attention is paid to the impact on network characteristics, primarily the average packet transmission time from source to recipient, the composition of routing metrics, service channel parameters, traffic intensity, and energy parameters of communication channels. The results from modeling allowed drawing conclusions about the feasibility of using various methods for organizing a service channel depending on the volume of transmitted routing information and evaluating the influence of routing metrics on the characteristics of the network in a stationary state and in the process of changing its structure. The approach proposed by the authors for assessing the efficiency of routing in a self-organizing network is applicable not only to UAV, but can be adapted for other unmanned vehicles (ground, surface, underwater) taking into account the peculiarities of their functioning and the propagation of radio waves.

Method for Defining the Automation Level of an eVTOL

Sarah Francisca de Souza Borges — 2024-09-23

Optimizing pilot-automation collaboration necessitates early safety assessment of the aircra!, which involves a rigorous examination of potential scenarios. "is article seeks to establish a comprehensive framework for safety analysis, exploring various levels of automation (LoA) within high-technology projects such as electric vertical takeoff and landing (eVTOL) aircra!. "e method is divided into three phases: the $rst involves de$ning the operations concept; the second involves applying the systems theoretic process analysis (STPA) method; and the third encompasses determining the safest LoA. Furthermore, this article scrutinizes the landing operations of eVTOL aircra! in urban centers. "e identi$ed control actions (CAs) include %ight monitoring, landing veri$cation, speed selection, and maneuvering. Ultimately, a LoA categorized as automated decision making emerged as the safest. "is entails the concurrent monitoring and generation of alternatives by both the pilot and the autopilot, with the $nal selection of the optimal alternative and its subsequent implementation exclusively entrusted to the autopilot. "iswork contributes by presenting evidence that safety analysis should commence at the level of individual CAs, rather than at a higher level encompassing complete operations or the entire aircra!. "is approach aims to generate comprehensive, practical, and effective safety requirements.

Comparative Analysis of Options for Organizing Internet Traf!c Exchange in Territorially Distributed Communication Networks

Gennady Chechin — 2024-09-09

The choice of the structure of the internet traffic exchange network is an urgent task for countries located with large areas. A mathematical model of this network with two Internet exchange points (IXes) in the form of a queuing network has been developed and analyzed. The proposed model, which, if necessary, can be generalized to the case of an arbitrary number of IXes, allows calculating the main characteristics of the network, determining its optimal parameters and analyzing alternative construction options: average round-trip delay (RTD), channel capacity, calculate the performance of traffic exchange nodes under reliability and cost constraints, and topology selection for the traffic exchange network, considering the main parameters. The results of calculations for Internet traffic exchange networks with uniform and significantly uneven loading of network channels are presented. An Internet traffic exchange network with several IXes can provide a lower delay, higher availability, and lower costs for implementation and commercial operation. In this case, a network with several IXes will enable the owners of these nodes and regional telecom operators to improve service and gain economic benefits.

Optimal Magnetorquer Rod Design for Small-Size Satellites using Axiomatic Design Theory and Nanocrystalline Material Core

Luiz de Siqueira Martins-Filho — 2024-09-23

The magnetic torquer rod, also called a magnetorquer, is the most popular actuator for attitude control of satellites in low Earth orbit. In the case of nano and picosatellites, the available inner space is quite limited, as is the maximum power value. An optimal design solution is highly desirable to produce adequate torque while minimizing energy consumption and mass. Based on the axiomatic design theory, a solution was developed by establishing the requirements – wire diameter, magnetic dipole moment, voltage, and solenoid length – and the physical domain variables – number of turns, current, resistance, and wire length. As a result of the modelling, the design system is decoupled. The choice of core material can also contribute to the actuator’s improvement. Two options are proposed in this work: the FINEMET, a nanocrystal composed of various metals and other elements, and the FeNi50 alloy, for comparative performance. In terms of design parameters, four prototypes were developed to evaluate different wiring configurations and two core materials. The test results of the design options reveal a contrasting performance concerning core material: while the utilization of nanocrystalline material yields superior hysteresis characteristics or linearity behavior, the FeNi50 alloy exhibits enhanced magnetization magnitude.

Constraint Control System Design for Double-Body Aircraft and Implementation on a Simulation Platform

Amir Azizi — 2024-08-12

In this paper, the modeling, open-loop analysis, and design of the constraint control system of the double-body aircraft are discussed. In a double-body aircraft configuration, two identical aircraft are connected using a one degree-of-freedom (1DOF) joint about the longitudinal body axis (hinges at the wingtips). Due to the long-term flight of the aircraft at high lift coefficients and the very high aspect ratio (AR) of the aircraft, controlling the angle of attack and the yaw rate is crucial to staying within safety limits. Additionally, the constraint control algorithm must be implementable in microprocessors to minimize weight and energy consumption. In the present research, a centralized control system with a sliding mode command governor (SMCG) is proposed to address these issues. First, the double-body aircraft was modeled using the Newton-Euler method. A nominal control system was designed with a linear control law, and then a SMCG is presented. To validate the constraint control system, numerical simulation and experimental testing were performed using a double-body simulation platform. The simulation and experimental test results indicate that the proposed control system performs well, with no deviation of the desired states from the limitations accrued.

Experimental and Numerical Investigation of the Natural Frequency for the Intact and Cracked Laminated Composite Beam

Raghad Azeez Neamah — 2024-08-12

In this study, several composite beam samples were made from woven fiberglass and epoxy. The first sample was created using epoxy, whereas the others used epoxy together with fiberglass layers. These samples were used to study, experimentally and numerically, the effect of fiberglass layers on the natural frequency of composite beams. A numerical model was constructed using ANSYS software 17.2 to assess vibration properties for the manufactured samples. The effects of boundary conditions (simply supported, clamped-clamped, and clamped-free), with crack depths (2 mm and 3 mm) and the number of fiberglass layers (0, 1, 2, 3, and 4) were investigated. The results of the experimental and numerical models were compared, and the numerical model was acceptable with an error rate of less than 15%. Crack depth has a significant impact on natural frequency and mode shape; therefore,

Identifying Technological Trends and Promoting Strategies to Boost Innovation and Technology Transfer: A Case Study on the Patent Portfolio of Brazilian Public Research Institutions

Nestor Brandão Neto — 2024-08-12

The development of innovative technologies represents a fundamental pillar for economic and social progress in countries, and understanding the opportunities for utilizing these technological solutions is a critical success factor. The dynamics of the technology transfer (TT) process are determined by the peculiarities of factors related to both the consumer market and the business environment in which scientific and technological institutions (STIs) operate. In the aerospace and defense sector, technologies have high dual-use potential and interest various industrial sectors. This manuscript explores emerging trends and the potential for TT of the intellectual property (IP) portfolio of these STIs across a diversified spectrum of significant technological areas in the industrial sectors. It is a case study applied to public STIs, seeking to understand the trajectories of technological development and anticipate their impact on the Brazilian productive sector. This focus is relevant as it addresses critical aspects affecting research, development, and innovation (RD&I) in public STIs, which are all essential to deciphering the complexities of the contemporary technological innovation ecosystem. This study offers valuable insights for researchers and managers of RD&I and TT, highlighting the critical role of technology in understanding the dynamics of innovation and managing of RD&I in the sector in focus.

Definition of Needs and Requirements for an Accessible Cabin on Regional Aviation

Silvio Romero Oliveira Nascimento Filho — 2024-07-08

The global increase in the number of passengers with disabilities in the aviation market raises the need for airlines to offer an inclusive service to these groups, which can represent a differentiation in the market. This paper is part 1 of a two-part series where it was proposed to apply a methodology inspired on Design Thinking, with tools such as persona mapping and user’s journey to define requirements and propose a concept for an accessible cabin. In this part, bibliographic research, with study of other papers that investigated the aviation market and mapped the complaints and needs of users with disabilities were initially carried out. The result of these researches served as the basis for the application of the methodology and definition of needs and requirements for an accessible cabin concept. It was concluded with this work that it is crucial to consider the needs of all stakeholders involved in the system for the good definition of the needs, that is, users, manufacturers, and airlines, since modifications to the cabin can affect important parameters such as cost and weight, and must be made to address points that can really improve the user experience. It was noted that research is limited for passengers with sensory impairments making it harder to clearly define their needs. Passengers with mobility restrictions, on the other hand, are better represented in research. Finally, the proposed list of needs demonstrates the potential to enhance the flight experience for passengers with special needs, potentially increasing their market share and overall satisfaction.

Proposal of an Accessible Cabin Concept on Regional Aviation for Passengers with Disabilities

Silvio Romero Oliveira Nascimento Filho — 2024-07-26

Despite a global increase in the number of passengers with disabilities on regional aviation, most aircraft cabins are still not adequately equipped to provide sufficient comfort to this public, making the travel experience much less attractive. In order to investigate how airlines and aircraft manufacturers could improve the cabin’s accessibility, this study aims to investigate solutions and systems available in the market to propose an accessible cabin concept for regional aviation. This research is part 2 of a two-part series that aims to apply a methodology inspired by Design Thinking Tools such as persona mapping to suggest improvements for the experience of passengers with disabilities. To this end, potential systems were evaluated and a cabin concept was proposed. It was noted that for passengers with sensory impairments, it is possible to improve their experience without major cabin modifications. However, research on their needs is limited and there are few solutions on the market targeting this audience. Conversely, passengers with mobility restrictions pose more complex challenges. Finally, the proposed accessible cabin concept demonstrates the potential to enhance the flight experience for passengers with special needs, potentially increasing their market share and overall satisfaction.

Unification of Training Programs for Aviation Professionals as a Flight Safety Criterion

Nadezhda Dolzhenko — 2024-01-09

The research relevance is predefined by the air travel number growth. Accordingly, the relevance of this issue is increasing, especially concerning air travel safety. Also, due to the increasing demand for international flights, it becomes essential to harmonize the standards and methodology of training aviation personnel. The research aims to consider the parameters of flight safety and the impact of the unification of training programs for aviation personnel. The conclusion that unification can significantly affect safety was made with the help of scientific and special methods, including analysis, synthesis, concretization, and generalization. An analysis of existing unification methods was conducted. The multi-crew pilot training program proved to be one of the most advanced compared to standard flight crew training programs. The method was determined to be a specialized training program tailored to the needs of the aviation industry and focused on training pilots for multi-crew and jet operations. The program is more challenging, intensive and dynamic, and includes a significant amount of simulator training. Traditional flight training programs, such as Private Pilot Licenses (PPL), Commercial Pilot Licenses (CPL), instrument qualification, and multi-engine rating, have a broader scope and provide pilots with more career opportunities. Simulator training has been identified as a critical component of many flight training programs and plays a vital role in flight safety. The study may be of interest to a range of readers concerned with the issue of standardizing aviation training and improving safety in aviation, including researchers, faculty, and students of higher education institutions in the aviation field.

On Structure and Secondary Linkages in Polymers Based on Glycidyl Azide Polymer and Diisocyanate

Christiane Bueno Dall´'Agnol — 2024-02-19

Polymers based on glycidyl azide polymer (GAP) and isocyanate present molecular structures dependent on NCO/OH molar ratio and diisocyanate reactivity. In this study, GAP polymers are obtained from a reaction with aromatic (toluene diisocyanate, TDI) or aliphatic (isophoranediisocyanate, IPDI) diisocyanates, varying the NCO/OH molar ratio from equimolar to 2.5. The increment in NCO/OH molar ratio increases the gel fraction in GAP/TDI polymers up to 90 wt%, along with a progressive growth in their glass transition temperature (Tg), which rises 10 °C from NCO/OH equimolar to 2.5. In opposition, in the GAP/IPDI polymers, the maximum gel fraction is 20 wt%, and the Tg value practically does not change in NCO excess. Infrared spectroscopy shows the predominant presence of urethane groups in polymers containing up to 2.0 NCO/OH molar ratio; however, at 2.5, urethane and allophanate characteristic bands are present in both polymers. That reactivity is controlled by chemical kinetics since the activation barrier of the reaction between the GAP and TDI is 10 kcal.mol^‑1 lower than in the corresponding reaction with the IPDI. This difference results from the sum of the higher hyperconjugative interactions, approximately 65%, and the lower steric hindrance, about 35%, in the activated complex containing the TDI.

Orbit-injection Strategy to a Multistage Launch Vehicle Based on Six-Degree of Freedom and Coupled Axes Attitude Control System

Daniel Furlani Aguiar — 2024-03-18

Understanding of various aerodynamic factors involved in flight trajectories is fundamental to design launch vehicles. First and foremost, computer simulation is an efficient way of predicting its behavior in the movement across the atmosphere. Considering that the available Brazilian version of Analysis, Simulation and Trajectory Optimization Software for Space Applications (Astos) does not simulate a controlled vehicle in six degrees of freedom (DoF), the aim of this article is to complement the Astos outcomes, particularly evaluating the trajectory of a controlled launch vehicle from liftoff to orbit injection, considering the model of rigid body dynamics with a six DoF. This approach carried out with an in-house developed simulator called Scott that simulated a multistage launcher with three flight configurations. In the Scott computer program, a launcher was modeled with differential equations in six DoF, coupled axes attitude control system, and aerodynamic coefficients that changed as a function of Mach number. These features improved the results generated by Astos software for the same configurations and the same initial conditions. Additionally, the results provided by Scott were close to actual vehicle in terms of attitude change and Mach number reached.

Strategy and Evaluation of Bilateral Agreement on Telemetry, Tracking, and Control Activities in Indonesia

Intan Perwitasari — 2024-02-19

India and Indonesia propose a bilateral cooperation to develop and operate telemetry, tracking, and control (TCC) ground stations to support satellite missions on geostationary orbits with the use of Geostationary Satellite Launch Vehicle (GSLV) since 1997, in order to master and commercialize space technology. This cooperation needs to be assessed in order to identify how it will affect Indonesia and India and to establish an improvement strategy for improved business and ways to integrate. !e objectives of this paper are to (i) evaluate the benefits and cost of this cooperation, (ii) map the business model of the telemetry, tracking and command ground station in Biak, and (iii) design a new strategy to get competitiveness. Descriptive analysis with canvas mapping and transaction cost perspective is the approach utilized. The article’s results highlight that (i) Indonesia and India have mutual benefits from tangible and intangible side, (ii) Indonesia has a competitive advantage due to its geographic location and commercialization of Biak Ground Station, so its potential to Telemetry, Tracking, and Command (TT&C) commercial businesses in the future, not only to domestic, but also international market, and (iii) Indonesia needs collaborate with commercial entities and making optimum diplomation with G2B schema to get beneficially among parties to maximize TT&C infrastructure in Biak Island.

Robust Finite-Time Control for Guidance Law with Uncertainties in Missile Dynamics

Fazhan Tao — 2024-02-19

In this paper, the robust !nite-time control for impact angle guidance of missile dynamic system with uncertainties is investigated by combining linear extended state observer (LESO) and adaptive non-singular fast terminal sliding mode method. Specially for dealing with existing uncertainties including time-varying parametric perturbation and nonparametric disturbances in high order line-of-sight rates and target acceleration, a robust LESO strategy is proposed for designing sliding mode-based impact angle guidance, which can guarantee that estimation error converges to the neighborhood of the origin in finite-time. Based on the proposed LESO framework, an adaptive non-singular fast terminal sliding mode guidance law is considered for realizing interception of maneuvering targets, which can guarantee asymptotically stability of the system. Simulation results are shown for confirming effectiveness of the proposed guidance strategy of this paper. Compared with former methods, accuracy of estimation is increased by nearly two times, and miss distance is reduced by nearly two times.

Modified Gaussian Mixture Probability Hypothesis Density Filtering using Clutter Density Estimation for Multiple Target Tracking

Lifan Sun — 2024-04-15

Gaussian mixture probability hypothesis density (GM-PHD) filtering often assumes a uniform distribution of clutter in the observation area. However, in practice, clutter is often unknown and non-uniform, necessitating accurate estimation of its spatial distribution, non-uniformity, and temporal variations. To address this problem, we proposed a modified GM-PHD filtering method with clutter density estimation for multiple target tracking. In the proposed method, first, potential target measurements within the tracking gate are eliminated to obtain the clutter measurement set. Next, the clutter density around each target is estimated. Finally, the estimated clutter density is incorporated into GM-PHD filtering, to estimate the target state and clutter density in complex clutter environments. Simulation results demonstrated that the proposed filtering method improves the performance of the GM-PHD filter in multi-target tracking scenarios with unknown clutter density.

Trends and Prospects in the Use of Energetic Materials: A Comprehensive Analysis of Cyclotrimethylenetrinitramine, Cyclotetramethylene-tetranitramine, and Hexanitrohexaazaisowurtzitane

Thiago Augusto Barbieri de Oliveira — 2024-04-29

This article provides a detailed look at how cyclotrimethylenetrinitramine (RDX), cyclotetramethylene-tetranitramine (HMX), and hexanitrohexaazaisowurtzitane (HNIW or CL-20) are currently being used for energy purposes in both civilian and military environments around the world. It highlights the significance of monitoring and prospecting for new technologies to promote innovation in developed and developing countries. This research was carried out by systematically analyzing nonpatent documents and patents from reputable databases such as Scopus, Derwent, and Espacenet. The report recognizes patent documentation as a valuable source of technical information and explores how analyzing patents can provide insights into using and developing high-performance compounds. Moreover, the article discusses the versatile applications of RDX, HMX, and CL-20, which are highly explosive substances that have found uses in multiple sectors. It delves into these materials’ chemical composition, structure, and importance in military and industrial contexts. The research methodology involved thoroughly searching and filtering documents from databases, focusing on titles, abstracts, and keywords. The results show the annual growth of publications related to the three explosive compounds and highlight the main research fields associated with each fabric. Overall, this article provides valuable insights into using and developing powerful compounds. It emphasizes the importance of technological monitoring and patent analysis in shaping strategic decision- making and fostering innovation. It is a foundation for further research and exploration of energetic materials and their applications.

Aeroacoustics Effects Generated by the Interaction Rotor-Airframe in a sUAS

Gino Rodrigo Lavagnino Sanchez — 2024-05-20

Small multirotor unmanned aerial systems (sUAS) have become more accessible and efficient recently, spurring their development for various personal and commercial uses. However, this rapid evolution raises concerns about security, control, and public health due to the proliferation of noisy drones. This study focuses on investigating a major noise source in drones called rotor-airframe interaction, which generates tonal noise through pressure fluctuations and wake interactions. To address this issue, we designed and tested three airframes with varying arm configurations. High-definition microphones and data acquisition systems were employed to measure pressure levels, and MATLAB code helped analyze the data as A-weighted signals to identify noise reduction possibilities. The key finding was that motor noise was a significant contributor, producing multiple pure tones at mid and high frequencies. Additionally, the noise signature was heavily influenced by the arm’s geometric shape and angles, underscoring the complex nature of rotor-airframe flow and acoustic interactions.

Multi-Objective Mission Planning for Multi-Payload Satellite Constellation via Non-Dominated Sorting Carnivorous Plant Algorithm

Yongkang Zhang — 2024-06-10

This study investigates the issue of multi-objective mission planning for multi-payload satellite constellations via the nondominated sorting carnivorous plant algorithm (NSCPA). Observation time windows are generated, and a constraint satisfaction model is established based on multiple regional targets, satellite orbits, and characteristics of the synthetic aperture radar (SAR) payload and optical payload. A task conflict detection and resolution method is proposed to handle the task assignment among multiple satellites. Based on the existing single objective-based CPAs, a modified multi-objective NSCPA is first developed for multi-objective planning optimization using the non-dominated sorting algorithm. The effectiveness and superiority of the NSCPA are verified by a series of simulation experiments and comparisons with the traditional non-dominated sorting genetic algorithms-II (NSGA-II) and particle swarm optimization (PSO).

Assessment of Indicators for Updating Adjacency Matrix of Self-Organizing Flying Ad Hoc Network

Vyacheslav Borodin — 2024-07-08

The concept of a swarm of drones assumes the presence of a wireless ad hoc network, in which drones are network nodes and exchanging information with each other. This article is devoted to studying the behavior of an ad hoc network in a transient mode and assessing the characteristics of updating local adjacency matrices (LAM), which allow network nodes to autonomously form packet transmission routes. Using a simulation model, a comparison was made of two multiple access methods to a common data transmission channel in the process of updating matrices: cyclic and random (slotted ALOHA). The simulation results made it possible to determine areas of their effective application: slotted ALOHA is advisable to use with relatively high probabilities of packet distortion (of the order of 0.1 and higher), a numerous nodes (more than 40), and low network connectivity, and cyclic access (CA) is effective at a low level of distortion. It is shown that the completion of the process of updating adjacency matrices (AM) can be judged by such indicators of the exchange of routing information as the achievement of a certain threshold of the number of transmissions and a decrease in the level of network traffic.

Staging Optimization of Satellite Launch Vehicles: Application to a Microsatellite Launcher

Guilherme da Silveira — 2024-07-15

With modern technology, only a small percentage of the overall mass of a launch vehicle, usually less than 5%, can be used as payload mass. To achieve any acceptable performance, a key aspect that is exhaustively analyzed during vehicle design is the definition of the number and sizes of its stages. The problem of finding the best vehicle configuration for a given mission is called staging optimization. This work presents the formulation and a resolution method for the staging optimization of a launch vehicle. The problem is formulated as an optimal control problem (OCP) and, for its solution, a direct approach, employing a gradient-based algorithm as solver, is proposed. An application is performed for the Brazilian microsatellite launcher VLM-1. This vehicle has a notable characteristic that, in its nominal configuration, the first and second stages are very similar to each other (same solid rocket motor with the same quantity of propellant). Different vehicle configurations are investigated which result in an improvement in its performance. The obtained results show good agreement with those from a commercial optimization tool.

Performance Enhancement of a Variable Cross-Sectional Area Square Pipe Solar Heater

Noora A. Hashim — 2024-07-26

Recently, solar energy has become most favorable source of energy. It is sustainable and environmentally friendly, and one of the most common application of solar energy is the solar water heater, which has a wide commercial and domestic applications. To enhance the performance of this device, many modifications are recommended. The enhancements may involve changes in pipe shape or materials or in absorber plate manufacturing, or sometimes by using a thermal storage tank to maintain heating. In this study, a variable cross-sectional area pipe is used to enhance heat transfer. Firstly, the vertical length is increased at the outlet to 1.2-1.8 ratios, while the horizontal sides remain constant. Then, for the same ratio, the horizontal sides are varied while the vertical sides remain constant. Finally, both the vertical and horizontal sides are increase. A three-dimensional numerical analysis is used to investigate the conjugated heat transfer and the flow characteristics in the pipe under study for each case. FLUENT ANSYS 17.2 is used to achieve this analysis using finite volume technique. Energy, Navier-Stokes, and continuity equations are solved at constant heat flux condition for a range of Reynolds numbers from 100 to 500. The hydraulic-thermal function ε is adopted in this study. The best increase in ε is 48%, achieved in the case of changes to both vertical and horizontal dimensions at a ratio of 1.8. The lowest percentage of decrease in pressure drop is 9.7%, and the highest temperature difference found is and 45.5% for the same case when compared with the uniform case for Reynolds number of 100. The present work is validated with another study adopting Shah’s empirical relation with a very good agreement.

Quality Management Systems’ Strategic Structure Oriented to Organizational Needs Management

Joel Carlos Vieira Reinhardt — 2024-05-20

This article proposes a new approach to implement a quality management system’s strategic structure that incorporates prospective scenarios analysis in the determination of strategic elements, such as quality policy, mission, vision, needs, and objectives. The qualitative analysis of managers’ statements about how the results were perceived revealed a significant change in strategic structure of a study case organization within the Department of Science and Aerospace Technology. This main result of this approach lies in the reorientation of managerial focus, prioritizing organizational needs management. This realignment culminates in superior results, obtained through effective actions aimed at fully satisfying these needs, thus marking a break with historical management practices.