Aircraft Weight Research Articles

Eco-Friendly Sol-Gel Coatings with Organic Corrosion Inhibitors for Lightweight AZ61 Alloy.

The latest advances in technology and materials science have catalyzed a transformative shift towards the adoption of environmentally conscious and lightweight materials across key sectors such as aeronautics, biomedical, and automotive industries. Noteworthy among these innovations are the magnesium-aluminum (Mg-Al) alloys employed in aeronautical applications, contributing to the overall reduction in aircraft weight and subsequently diminishing fuel consumption and mitigating atmospheric emissions. The present work delves into a study of the anti-corrosive properties inherent in various sol-gel coatings, leveraging a range of environmentally friendly corrosion inhibitors, specifically tailored for samples of the AZ61 alloy. Methodologically, the work involves the synthesis and application of sol-gel coatings on AZ61 alloy containing eco-friendly inhibitors: L-cysteine, N-acetyl-cysteine, curcumin and methylene blue. Subsequently, an accelerated corrosion test in a simulated saline environment is performed. Through microstructural and compositional analyses, the best inhibitors responses are achieved with inhibitors containing S, N heteroatoms and conjugated double bonds in their structure, probably due to the creation of a continuous MgCl2 layer. This research contributes to the ongoing discourse on protective eco-coatings, aligning with the broader paradigm shift towards sustainable and lightweight materials in key industries.

Fluidic Flow Control Devices for Gust Load Alleviation

A reduction in the structural weight and climate-relevant emissions of future transport aircraft can be realized through active gust load alleviation, limiting the peak aerodynamic loads experienced in flight. Two fluidic concepts, surface and Coandă jets, offer promising solutions. The surface jet induces a separated flow region on the wing’s suction side near the trailing edge, while the Coandă jet utilizes tangential blowing over a rounded trailing edge to make use of the Coandă effect for direct circulation control. This study investigates these fluidic actuation concepts using two-dimensional unsteady Reynolds-averaged Navier–Stokes simulations on a supercritical airfoil to alleviate gust-induced lift increases. Results reveal that fluidic concepts can surpass the load reduction capability of a trailing edge flap. Notably, the Coandă-type design, while more efficient, exhibits limited control authority compared to surface jet, achieving maximum gust load reductions of 40% versus 70% for surface jet. Optimizing the temporal deployment of the surface jet leads to increased peak lift reduction. Even under challenging conditions with reduced gust anticipation time and actuator placement near the wing tip with a reduced chord length, the surface jet maintains consistent performance and therefore offers a promising solution for active gust load alleviation on future aircraft.

Development of Electronic Flight Bag Application for Small Turboprop Aircraft Weight and Balance Calculation

Nowadays, many airlines in modern aviation utilize an Electronic Flight Bag (EFB) during flight to replace traditional paper-based systems. Considering the importance of aircraft weight and balance calculation to flight operations, the flight mission of X-123 (a small turboprop aircraft) and the current EFB market, research on weight and balance application development of X-123 on EFB in Indonesia is conducted. The research aimed to develop the application according to Indonesian regulations and to examine the weight and balance characteristics of X-123 through several simulations in a programming language, Python. Furthermore, Staff Instruction 8900 - 3.3 is analyzed to identify the factors that should be considered in EFB development. The global architecture design and substantial features are, then, proposed as an initial EFB development. In the global architecture design, the utilization of a gateway becomes important as a connection between the EFB developer and the client, providing aircraft data changes flexibility to the client. Moreover, the calculation formula is completely discussed in the calculation modules as a substantial feature and implemented in the simulation. According to simulation results, the payload weight and payload distribution changes can affect significantly the CG location. It is recommended to weigh and assign the payload before flight to ensure flight operation safety. In addition, the proposal of the architecture design and substantial features can be used as a reference and further developed by the Indonesian aviation companies.

Advancing Electric Flight through Innovative Materials in Aerospace Propulsion Systems

The advent of electric aircraft heralds a transformative era in aviation, offering a sustainable alternative to conventional aircraft that significantly contribute to carbon emissions. This paper discusses the application of advanced materials in overcoming the technical hurdles associated with electric propulsion systems, focusing on their application in airframe construction, electrical conductors, thermal management, and battery technology to enhance the performance and sustainability of electric aircraft. Advanced composites like carbon fiber reinforced polymer (CFRP) are explored for their potential to reduce aircraft weight and improve mechanical properties. The paper also addresses the challenges of thermal management in electric propulsion systems, highlighting the use of phase change materials (PCMs) and advanced ceramics for efficient heat dissipation. Furthermore, the exploration of high-energy-density cathode materials, innovative anode materials, and solid-state electrolytes is discussed in the context of developing lightweight, high-capacity batteries for electric aircraft. Despite the promising advancements in material science and the potential benefits of electric aviation, the paper acknowledges the existing challenges, including the high cost of advanced materials, the need for improved energy storage solutions, and the environmental impact of material production.

Benefits and Challenges of Electric Propulsion for Commuter Aircraft

This paper presents the Library for Unified Conceptual Aircraft Synthesis (LUCAS) sizing and optimization framework, which is largely based on Stanford’s Stanford University Aerospace Vehicle Environment (SUAVE). LUCAS is applied to a commuter mission carrying 19 passengers. Results show that energy usage benefits depend on mission range and electrical component technology and that reserve requirements play a significant role in the feasibility of electrified aircraft. It is found that storing more energy in batteries rather than fuel reduces the mission energy requirement at the expense of aircraft weight growth. All-electric aircraft could provide onboard energy savings of upward of 30% for a 180 km mission, but this would only become feasible if battery specific energy reached the high value of 900 W⋅h/kg. Range could be increased to 550 km if part of the reserve mission requirements is relaxed. Under more realistic technology assumptions, a hybrid design storing energy in fuel and batteries could fly commuter missions with energy savings of 6%. A beneficial use case of hybrid configurations is a mode of operation where the aircraft uses only batteries during the main mission and fuel to store all the reserve energy. If reserves are not required for a particular flight, energy savings are still maximized, while the availability of fuel ensures certification requirements are met with fewer penalties.

BOEING 787 Model Daha Elektrikli Uçak Sistem Yenilikleri ve Araştırılan Sorunları

In recent years, MEA technology has brought about developments in the field of power electronics, fault-tolerant architecture, electro-hydrostatic actuators, flight control systems, high-density electric motors, power generation and conversion systems. Non-propulsive systems in traditional aircraft systems, ıt is powered by a combination of different secondary power sources such as hydraulic, pneumatic, mechanical and electrical while the more electric aircraft (MEA) concept ensures the use of optimum electrical power for all non-propellant systems. 
 The goal of future aircraft technology is to replace the majority of non-electrical power-using systems, such as environmental control and engine starting, with electrical systems to improve various aircraft characteristics such as efficiency, emissions, reliability and maintenance costs. B787 series aircraft, the first civil aircraft with more electric aircraft features of modern times, ıt features composite fuselage and wing profiles, fly-by-wire flight controls, advanced cockpit and General Electric or Rolls-Royce engines. Different from previous designs, Boeing has minimized the use of air from the engines in the B787 technology and makes extensive use of electrically powered systems instead of traditional pneumatically powered systems. B787 new generation passenger aircraft, ıt is anticipated that significant improvements such as aircraft weight, fuel consumption, total life cycle costs, carbon neutrality, ease of maintenance and aircraft reliability will reduce the effects of adverse environmental conditions.
 In this study, the system innovations of the B787 aircraft model, which is a more electric aircraft concept and introduces different testing and working methods throughout the design process, and the problems caused by the new systems were investigated.

Destruction of reinforced concrete structures of sewage systems

Composites materials are artificially created materials that consist of two or more components that differ in composition and are separated by a pronounced boundary. The development of modern composite materials is associated with the discovery of high-strength whiskers, with the study and use of aluminides and high-strength alloys. At present, various composite materials have been developed and used: fibrous; reinforced with whiskers and continuous crystals and fibres of refractory compounds and elements; dispersion-hardened materials; layered materials; alloys with directional crystallization of eutectic structures; alloys with intermetallic hardening. There are many technologies for producing composites: imbibition of reinforcing fibres with matrix (base) material; cold pressing of components followed by sintering; sediment of the matrix by plasma spraying on the hardener, followed by compression; batch diffusion welding of multilayer tapes of components; joint rolling of reinforcing elements with a matrix, and etc. The use of composites makes it possible to reduce the weight of aircraft, cars, ships, increase the efficiency of engines, and create new constructions with high performance and reliability. The development of composites with high impact resistance is an important direction in the industry. The strength characteristics of a layered composite material are decisive under shear loads, loading of the composite in directions other than the orientation of the layers, and cyclic loading. In this paper, we study the non-stationary interaction of an absolutely rigid body on a two-layer reinforced composite material. The action of the striker is replaced by a non-stationary vertical even distributed load, which changes according to a linear function, in the area of initial contact, which is assumed to be unchanged over time.
 In contrast to the previous articles (Parts I and II), in this papers there is an investigation of the strain-stress state, the fields of the Odquist parameter and normal stresses depending on the material of the first (upper) layer.

Finite Element Analysis of the Main Structure for a New Conceptual Aircraft Passenger Vertical Seat Design

Standing cabin is a new design concept of aircraft passenger cabin whereby passengers are transported in the standing position throughout flight as opposed to current seated position. An important element of this cabin concept is the design of the vertical seat to support the passengers, which has to be in compliance with requirements of aviation regulation. In commercial aircraft applications, weight of passenger seat is a significant factor that can affect flight performance of the aircraft. Meanwhile, the seat’s structure should have adequate strength to ensure proper safety provision to passengers. Hence weight and strength are potentially two conflicting design requirements for the vertical seat, and the optimum structural design should have the best compromise with regards to these two requirements. In this study, parametric study on primary structural design of the proposed vertical seat concept is done to obtain an optimized design that satisfies the strength requirements for safety of passengers without causing high penalty to the overall aircraft weight and performance. The simulation analysis for the main structures of the vertical seat design is conducted through finite element method using ABAQUS software. From the results of the analysis, main structural parts made from aluminium alloy with diameter 90 mm and thickness 3 mm are selected for the optimum vertical seat design. This standing seat design has also been shown to have adequate strength and can satisfy the safety regulation requirement without failure. The maximum stress on the seat’s structure under 9-g forward loading is found to be 147.5 MPa, which is lower than ultimate strength of aluminium. Moreover, the seat’s weight is estimated to be 9.5 kg and the maximum deflection of its main structures under forward 9-g loading is 28.42 mm. All in all, the stress analysis results highlight that the structural strength of the optimal vertical seat design can satisfy the requirements of the governing aviation regulations to provide safety to passengers.

Performance analysis of electrical environmental control and ice protection systems in a commercial transport aircraft

PurposeThis paper aims to assess the impact of electrifying the environmental control system (ECS) and ice protection system (IPS), the primary pneumatic system consumers in a conventional commercial transport aircraft, on aircraft weight, range, and fuel consumption.Design/methodology/approachThe case study was carried out on Airbus A321-200 aircraft. Design, modelling and analysis processes were carried out on Pacelab SysArc software. Conventional and electrical ECS and IPS architectures were modelled and analysed considering different temperature profiles.FindingsThe simulation results have shown that the aircraft model with ±270 VDC ECS and IPS architecture is lighter, has a more extended range and has less relative fuel consumption. In addition, the simulation results showed that the maximum range and relative fuel economy of all three aircraft models increased slightly as the temperature increased.Practical implicationsConsidering the findings in this paper, it is seen that the electrification of the conventional pneumatic system in aircraft has positive contributions in terms of weight, power consumption and fuel consumption.Social implicationsThe positive contributions in terms of weight, power consumption and fuel consumption in aircraft will be direct environmental and economic contributions.Originality/valueApart from the conventional ECS and IPS of the aircraft, two electrical architectures, 230 VAC and ±270 VDC, were modelled and analysed. To see the effects of the three models created in different temperature profiles, analyses were done for cold day, ISA standard day and hot day temperature profiles.

Neural Network‐based Method to Compute Recommended Cruise Level and Optimal Climb Location

AbstractSystem engineering towards utilizing machine learning solutions in the aviation domain is a fast‐progressing discipline. This paper tries to bring out the system engineering and implementation aspects of ML solution as an improvement in a sub‐system of an existing aviation system. The flight management systems (FMSs) compute the recommended cruise level (RCL) considering the aircraft's gross weight, its speed schedule, and the forecast wind. The RCL increases with distance in the no wind conditions as the fuel get consumed, reducing the gross aircraft weight. The RCL profile may have frequent climbs and descents in the presence of winds, which is not desired for flight operations.The document proposes a neural network‐based method for computing an operationally acceptable cruise profile considering the wind and temperature weather forecast. The method recommends step climbs and step descents (optimal level and optimal step location) in such a way that they are separated by a large enough cruise phase. From system engineering point of view two guiding documents for such an implementation to look forward are “EASA Concept Paper: First usable guidance for Level 1 machine learning applications” [12] and “Process Standard for Development and Certification/Approval of Aeronautical Safety‐Related Products Implementing AI” [13].Two neural networks have been created to estimate wind compensated ECON cruise speeds and required time‐fuel to cover the next 500NM distance. The RCL profiles are generated for various test wind scenarios for Airbus A220 aircraft. It has been recorded the proposed neural network‐based method is better at recommending a cruise altitude and it is 9X faster than the existing method to calculate the RCL and optimal climb location. The neural network‐based design also helped in reducing the memory footprint by more than 100 times as there is no requirement of storing the performance database files required by the existing system. Only the parameters of the trained neural networks are required to be stored. Most importantly, the RCL computed by the proposed neural network‐based method yields a smaller operational cost than that determined by the existing method. The proposed method is designed to replace the existing traditional subsystem to give an overall improved performance while the functionalities of other subsystems remain unaffected.

The multi-objective optimization of material properties of 3D print onyx/carbon fiber composites via surrogate model

Composite materials play a prominent role in modern engineering. The emergence of composite material technology has brought about a profound impact on almost, if not all industries. The aerospace industry, for instance, benefits greatly from composite materials. With composites, aircraft weight can be reduced while the structural strength is maintained. As with other classes of materials, 3D printing technique allows composite parts of high complexity to be fabricated with great precision. Additionally, with 3D printing, mechanical properties of the resulted part can be accurately customized and controlled by means of varying matrix-reinforcement proportions. As the composite material can be indefinitely customized in 3D printing, it is crucial to evaluate the mechanical properties of the printed specimen. While testing of printed specimens is usually possible, endless production and testing of specimens not only takes time and resources but also leads to extensive experimental waste. In this study, an optimization-based technique is proposed to determine the optimal 3D printing material proportion in order to reduce the need of unwarranted experimental waste and improve the efficiency of composite material selection process. The study aims to investigate the properties of Onyx/Carbon fiber composite material and the optimization of the 3D printing configuration to achieve desirable mechanical properties. The effects of the number of carbon concentric fiber rings and the percentage of infill density of Onyx used in 3D printing were examined. ASTM D3039 tensile tests were performed to obtain mechanical properties of the printed specimen. Considering the values of tensile strength and modulus of elasticity of the printed material, the printing configurations were optimized using a multi-objective non-dominated sorting genetic algorithm II (NSGA-II) with the Kriging model for objective function estimation. From the proposed optimization technique, it has been found that the maximum tensile strength is attained when the number of concentric fiber rings is equal to 3 while the percentage of Onyx infill density falls in the range of 86–90. Contrarily, the modulus of elasticity is maximized when the number of concentric fiber rings is equal to 4 with the percentage of Onyx infill density in the range of 70–75.

Effects of Synthetic Jets on Swirl Inflow in a Variable-Geometry Twin Air-Intake

Air intakes are an integral part of contemporary passenger and military aircraft engines. Their impact on aerodynamic performance across the entire flight envelope is critical to aircraft flight safety, efficiency, and manoeuvrability, especially at high Mach numbers due to shock waves. The high demand for reductions in aircraft weight and size and enhancements in durability, comfort, and thermal and radar signatures compel researchers and engineers to explore new designs and develop efficient air intakes for high-performance aircraft engines. Although a number of studies on air intake have been conducted and reported in the open literature, there is little information available in the public domain on bifurcated twin air intakes using synthetic jet. As a result, the primary goal of this research is to use computational fluid dynamics modelling to investigate the effects of synthetic jets on swirl inflow variable geometry twin air intake aerodynamic performance over a range of Reynolds numbers. Some important parameters (distortion coefficient, non-uniformity index, swirl coefficient, and static and total pressure coefficients) were investigated. Both static and total pressure recovery have been increased at all swirl numbers. A significant decrease in distortion coefficient and swirl coefficient has also been achieved, reaching a 53% reduction in the distortion coefficient and a 62% reduction in the swirl coefficient. The reduction in the non-uniformity index is achieved by 62% for the controlled flow case. The findings show that synthetic jets are effective in controlling the flow separation in the twin air intakes and enhancing aerodynamic performance.

Research on High-Performance Multiphase DC–DC Converter Applied to Distributed Electric Propulsion Aircraft

The performance of power converter of electric propulsion aircraft (EPA), which should have high efficiency, high power density and high reliability, affects the volume, weight and efficiency of the whole electric aircraft (EA). This paper proposes a novel DC-DC converter with gallium nitride (GaN) transistors. Firstly, the working modes and main operation waveforms of the converter are analyzed. The new converter can achieve ZVS and ZCS through auxiliary soft switch branches. Compared with the traditional Buck-Boost converter, the soft switching capability of the proposed converter allows operation at very high frequency and has a higher efficiency. The multiphase interleaving magnetic integration technology is adopted to realize the modular design, which not only meets the requirements of high power and low ripple, but also eliminates right half-plane zero in boost mode, achieves high dynamic response and improves the power density. A novel parallel multiphase inverse coupled inductor (ICI) and a symmetrical array ICI are proposed, to allow a high-density and high-efficiency bidirectional DC-DC converter design for hybrid energy storage system of EPA. Finally, the proposed ICI prototype was compared with the state-of-the-art commercial ICI product, and the comprehensive performance of the converter was verified through steady-state, transient, efficiency and thermal experiments.

A method for the 3D identification of the center of gravity of an aircraft

The aircraft weight and balance are a consequence of the own mass and the payload distribution, resulting in a position of the Centre of Gravity (CoG) that affect the behavior of the aircraft, its stability and the control effectiveness.The aircraft weight is normally measured statically using ground scales or sensors in the landing gear axles or struts, driving to 2D measurements of the CoG in longitudinal and lateral directions. Sometimes the 3D measurement is relevant because the aircraft architecture can involve weight shifts, i.e., the tiltrotor case.This paper studies the fast 3D measurement of the CoG in a tiltrotor type aircraft using photogrammetry and scales without previous levelling the aircraft. The system is modelled using multibody simulations to obtain data for the validation of the proposed methods. Finally, the expected uncertainty of the measurement is evaluated using Montecarlo method, analyzing the results statistically.

A critical review of recent advances in the aerospace materials

The pursuit for improved performance in the aerospace and aviation industries has inspired the development, investigation, and research of advanced materials. Since the last few years, a lot of research on different alloys, composites and some other advanced materials has been performed to perfectly meet the needs of the aerospace field such as basic frames of aircraft, fuselages, engine parts, wings etc. Various aluminium, magnesium, titanium, and nickel-based alloys have been developed with certain advantages like strength-to-weight ratio, corrosion resistance, wear resistance etc. However, there are major challenges to aerospace materials such as insufficient mechanical and chemical properties, overall weight of aircraft, fretting wear, stress corrosion cracking, incapability at high temperatures, and low oxidation resistance. Therefore, vast studies have been conducted for the development of next-generation aerospace materials. In the present article, attention has been made to study the contemporary materials, current research going on and future trends on advanced materials in the field of aerospace engineering. Aluminium-based alloys are found as the most widely used metal alloys in the aerospace sector for their strong mechanical properties. However, polymer matrix composites and metal matrix composites have gained popularity due to their exceptional strength and stiffness. Titanium-based alloys are favoured for their strength and corrosion resistance, leading to increased adoption.

Numerical Solution of Inviscid and Viscous Flow Across NACA0010 Airfoil with different Angles of Attack

The role of the airfoil in all engineering fields is very important. Airfoil designs are utilized in various applications such as aircraft wings, helicopter rotor blades, sails, fans, and turbine compressors. In the case of aircraft, airfoils are accountable for generating lift force and determining if it is adequate for balancing the aircraft's weight, as well as determining the amount of drag force that should be applied to the body. They also play a vital role in optimizing blade performance, as well as the heat and operational efficiency of turbines. Airfoils are moving in the flow passing by them, and they show different responses based on many parameters such as whether the flow is smooth or turbulent, viscous or inviscid, flow velocity, angle of attack, multidimensionality of velocity components, etc. For aeronautics vehicles and wind turbines, a large number of studies have been conducted to analyze aerodynamic forces on two dimensional airfoils as well as flow phenomena associated with different Reynolds numbers. Main object of this research is to figure out the flow characteristics around the airfoil body and analyze aerodynamic performance of airfoil. In order to investigate the computational efficiency of flow models, numerical examination has been done for flow across NACA0010 airfoil by using 2D Computational Fluid Dynamics (CFD) solver, ANSYS FLUENT 18.0, at various angle of attack (0o to 13o) for inviscid flow and (-30o to 30o) for viscous flow. Lift and drag coefficients and C p for lower and upper airfoil surface and velocity diagram based on different angle of attack has been solved for the sample under two different flow regimes. The contours of velocity were simulated, and stall point was noticed from 13° angle of attack in inviscid flow and 24o in viscous flow. In the non-viscous state, lift coefficient and drag coefficient was higher, in comparison with viscous flow.

Design of a Hydrogen Aircraft for Zero Persistent Contrails

Contrails are responsible for a significant proportion of aviation’s climate impact. This paper uses data from the European Centre for Medium-Range Weather Forecasts to identify the altitudes and latitudes where formed contrails will not persist. This reveals that long-lived contrails may be prevented by flying lower in equatorial regions and higher in non-equatorial regions. Subsequently, it is found that the lighter fuel and reduced seating capacity of hydrogen-powered aircraft lead to a reduced aircraft weight, which increases the optimal operating altitude by about 2 km. In non-equatorial regions, this would lift the aircraft’s cruise point into the region where long-lived contrails do not persist, unlocking hydrogen-powered, low-contrails operation. The baseline aircraft considered is an A320 retrofitted with in-fuselage hydrogen tanks. The impacts of the higher-altitude cruise on fuel burn and the benefits unlocked by optimizing the wing geometry for this altitude are estimated using a drag model based on theory proposed by Cavcar, Lock, and Mason, and verified against existing aircraft. The weight penalty associated with optimizing wing geometry for this altitude is estimated using Torenbeek’s correlation. It is found that thinner wings with higher aspect ratios are particularly suited to this high-altitude operation and are enabled by the relaxation of the requirement to store fuel in the wings. An example aircraft design for the non-equatorial region is provided, which cruises at a 14 km altitude at Mach 0.75 with a less than 1% average probability of generating long-lived contrails when operating at latitudes more than 35° from the equator. Compared to the A320, this concept design is estimated to have a 20% greater cruise lift–drag ratio, due to the 33% thinner wings with a 50% larger aspect ratio, enabling just 5% more energy use per passenger-km, despite fitting 40% fewer seats.

A novel estimation method for weight and center-of-gravity via the aircraft trim data

Aircraft weight and center-of-gravity are significant parameters that affect flight stability and controllability, and unreasonable CG position may cause serious flight accidents. However, there is no airborne sensor can directly measure aircraft weight and center-of-gravity. In view of this, a novel estimation method for weight and center-of-gravity via the aircraft trim data is introduced. Specifically, the trim data calculation process for the aircraft with variable center of mass is given. Then, an inverse interpolation approach based on the binary search algorithm is presented to estimate the aircraft weight and center-of-gravity, and an improved moving average filter is introduced to eliminate the adverse effect on estimation results caused by the high-frequency noise of airborne sensors. Some simulations are given to demonstrate the validity of the proposed estimation method, and it can be drawn from the result that the aircraft longitudinal CG position estimation error is within 0.05 %MAC.

A Combinatorial Optimization Approach for Air Cargo Palletization and Aircraft Loading

The current air cargo loading plan handles the Air Cargo Palletization Problem (ACPP) and the Aircraft Weight and Balance Problem (WBP) separately, which has an impact on the optimization of the payload and the aircraft’s center of gravity (CG). Thanks to improvements in computer processing power, the joint combinatorial optimization of ACPP and WBP is now feasible. Three integer linear programming models are proposed: a Bi-objective Optimization Model (BOM), a Combinatorial Optimization Model (COM), and an Improved Combinatorial Optimization Model (IOM). The objectives of the models are the maximum loading capacity and the lowest CG deviation from a specified target CG. The models also consider a wide range of restrictions in the actual packing and stowage procedures, such as volume, weight, loading position, aircraft balance, and other aspects of aircraft and unit load devices. Four scenarios with various conditional metrics for three models are solved for the B777F aircraft using Gurobi. The results of the computations demonstrate that the BOM has the fastest solution speed, but the CG deviation is the largest, and in several cases the CG deviation results are unacceptable. The COM has the longest solution time, which is difficult to tolerate in practice. Despite taking a little longer to solve computationally than the BOM, the IOM offers the best optimization solution.

Dynamic recrystallization in friction stir welded AA2014 aluminium alloy joints to replace riveted joints

Abstract The demand for lightweight materials (aluminium and magnesium alloy) in structural applications is increasing due to strength ratio, corrosion resistance, formability, and recyclability. Fusion welding of aluminium and its alloy is difficult due to the formation of hot cracking, alloy segregation, porosity, etc. Henceforth, fusion welding is not an ideal process for joining aluminium and its alloy. Steel rivets are being used to join similar and dissimilar alloys in different joint configurations. Since the use of steel rivets, aircraft weight has increased drastically. Although, dissimilar metal corrosion has been encountered. These two are the main problems in structural fabrication industries. The solid-state welding friction stir welding process eliminates the issues mentioned earlier. This process can weld materials well below the melting point. Moreover, the formation of weld in the weld line could be achieved by severe plastic deformation and recrystallized grains. This metallurgical joint may replace the rivets.