Browse Topic: Aircraft structures

Items (3,656)
The integration of advanced horizontal axis turbines (HATs) into unmanned marine vehicles (UMVs) significantly enhances their operational efficiency by providing power sources. These vehicles, designed for diverse applications, require efficient power systems to operate autonomously over extended periods. The major disadvantages are limited battery life and energy storage capabilities that restrict the operational range and endurance of the UMVs. Utilizing HATs in UMVs provides a renewable energy source, reducing operational costs. This continuous power supply enhances mission capabilities and promotes energy independence, making them ideal for long-term missions. Thus, using Computational fluid dynamics (CFD) models, hydrodynamic and aerodynamic analyses were carried out. For the hydrodynamic scenario, a velocity of 10 m/s and for the aerodynamic case, 27.7778 m/s, were taken into consideration. It is concluded that the UMV with Stepped HAT modification can be effectively employed for
Gunasekaran, Durga DeviKannan, HaridharanSourirajan, LaxanaVinayagam, GopinathGnanasekaran, Raj KumarKulandaiyappan, Naveen KumarStanislaus Arputharaj, BeenaL, NatrayanRaja, Vijayanandh
This work deals with computational investigations of the component performances of Advanced Hexacopters under various maneuverings of the focused mission profiles. The Advanced Hexacopter is a kind of multirotor vehicle that contains more propellers and flexible arms, which makes this multirotor very maneuverable and aerodynamically efficient. This Hexacopter was designed specifically to execute multi-perspective applications along with enhanced payload-carrying capability. This Advanced Hexacopter contains a frame composed of modified arms equipped with coaxial rotors, which servo motors control. By providing specific and simple inputs to the microcontroller, the Hexacopter can autonomously undergo forward and backward maneuverings. The primary objective of this study is to analyze and compare different propeller configurational clearance sets that improve the maneuvering capability of this unmanned aerial vehicle (UAV), specifically emphasizing forward/backward and side maneuvering
Raja, VijayanandhNarayanan, SidharthElangovan, LogeshArumugam, LokeshSourirajan, LaxanaRaji, Arul PrakashKulandaiyappan, Naveen KumarGnanasekaran, Raj KumarMadasamy, Senthil Kumar
Exploration vehicles on Titan are to be developed with considerations on the atmosphere present, especially the abundance of Nitrogen. This study focuses on identification of optimum materials for the propellers supporting an airship specifically created for Titan exploration. The base airship is designed to accommodate the coaxial propeller. The base of this airship is to be developed with four weather stations for collection of data samples. The stations are installed on inflatable platforms and have storage devices for recording and transmitting data collected by the aerobot. The airship will operate in Titan's atmosphere and atmospheric conditions, focusing on its design and computational analysis of structural effects and fluid dynamics. The Titan aerobot is built with a co-axial 4-blade propeller, horizontal and vertical fins, and a reaction wheel for yaw maneuvers. The co-axial propulsive system is capable of overcoming drag during steady level flight in the Titan atmosphere
Baskar, SundharVinayagam, GopinathPisharam, Akhila AjithGnanasekaran, Raj KumarRaji, Arul PrakashStanislaus Arputharaj, BeenaL, NatrayanGanesan, BalajiRaja, Vijayanandh
This work focuses on the design and multi-parametric analysis of a designed propeller for a Pentacopter unmanned aerial vehicle (UAV). The basic and secondary design inputs, along with performance data like propeller diameter, pitch angle, chord length, and lift coefficient, are established using a standard analytical method. Approximately ten distinct airfoils, specifically NACA 2412, NACA 4109, NACA 4312, NACA 4409, NACA 4415, NACA 5317, NACA 6409, NACA 6412, NACA 23024, and NACA 25012, are evaluated over 13 Reynolds Numbers with the angle of attacks (AOA) of 20, varying from -5 to 15 degrees, for the purpose of detailed propeller design. The lift and drag coefficient values for ten distinct airfoils, utilizing a Reynolds number of 13 and 20 angles of attack, are obtained from the XFOIL software. Three sophisticated airfoils are selected from a pool of ten based on their high Lift-to-Drag (L/D) ratio performance. The selected airfoils with a high L/D ratio are NACA 6409, NACA 4109
Veeraperumal Senthil Nathan, Janani PriyadharshiniArumugam, ManikandanRajendran, MahendranSolaiappan, Senthil KumarKulandaiyappan, Naveen KumarMadasamy, Senthil KumarStanislaus Arputharaj, BeenaL, NatrayanRaja, Vijayanandh
This article explores the utilization of simple-cubic, diamond, octet-truss, and X-type lattice structures for low-pressure turbine blades in engine turbines to enhance natural frequency and decrease overall engine weight while maintaining structural integrity. The research method involves analyzing polylactic acid (PLA) hollow T106C blades with fully infilled and 50–80 location-based lattice arrangements. The study modifies the strut thickness of lattice structures using both constant and variable-based approaches and applies a generalized formula based on relative density to evaluate how changes in lattice thickness and arrangements influence natural frequencies. Furthermore, the investigation extends to multi-lattice configurations, introducing a parameter 𝑘 to signify the transition between different lattices. The modified blades were 3D printed using PLA and tested for natural frequencies through modal testing. The results demonstrate that location-based 50–80 exponential-based
Reewarabundith, Siwachai
The paper present numerical effects of supercritical airfoil SC (2) 0414 having circular cavities at three different chord wise locations from leading to trailing edge. Here passive control method is widely applied by altering the \baseline airfoil surface coordinates to ascertain the aerodynamic behavior of the cavity at 40 %, 50 % and 60 % of the chord length respectively. The cavity shapes were deformed using Bezier curve to observe vortex pattern in the cavity region. Structured meshing was employed. The analysis was performed on SC 2 (0) 414 two-dimensional airfoil using commercial CFD ANSYS Fluent software where Spalart- Allmaras turbulence model technique is chosen to solve boundary layer problems on adverse pressure gradient and tested at extended range of angle of attack (-150 to 150) at Mach number 0.85. The study highlights the aerodynamic characteristics of lifting coefficient, drag coefficient and lift to drag ratio. It was observed that the cavity in suction surface
Pushparaj, Catherine VictoriaP, Booma DeviD, PiriadarshaniGanesan, BalajiGanesan, Santhosh KumarRaja, Vijayanandh
The inductance parameter is important for the flux regulation performance of the hybrid excitation motor, and the axial structure leads to the change in the inductance parameter of the axial-radial hybrid excitation motor (ARHEM). To clarify the inductance characteristic of the ARHEM with different winding construction and the mutual coupling effect between the axial excitation and permanent magnet excitation on the inductance. Firstly, the structure of the ARHEM is presented. Secondly, the self and mutual inductance characteristics of ARHEM are analyzed using the winding function method. Then, the influence of the axial excitation structure on the armature reaction field and saliency ratio of ARHEM. On this basis, the mechanism of the mutual coupling, between the axial excitation and permanent magnet field under different excitation currents on the main air gap magnetic field, and the inductance of ARHEM with fractional slot are revealed.
Fu, DongXueZhao, HeweiWu, QiminYuan, ChunweiWang, DongQiu, Hongbo
Monitoring the rotor temperature of drive machines is crucial for the safety and performance of electric vehicles. However, due to the complex operating conditions of electric vehicles, the thermal parameters of vehicular induction machines (IMs) vary significantly and are difficult to identify accurately. This article first establishes a concise but effective thermal network for IMs and analyzes the influencing factors of thermal parameters. Then, a parameter identification network (PIN) with multiple parallel branches is constructed to learn the mapping relationship between electromechanical variables and thermal parameters. Afterward, temperature datasets for network training are built through bench testing. Finally, the effectiveness of identified parameters for rotor temperature estimation application is verified, demonstrating improved interpretability, generalization ability, and accuracy compared to an end-to-end neural network.
Jiang, ShangHu, Zhishuo
This paper designs a low-budget yokeless and segmented armature (YASA) axial flux permanent magnet synchronous machine, which replaces some of the PMs attached to the rotor with silicon steel plates. For the purpose of checking the effectiveness of the proposed machine, the equivalent magnetic circuits of the typical and proposed YASA machines are first compared and analyzed, and then the models of the two machines are constructed and simulated. The results prove that the proposed YASA machine significantly reduces the quantity of permanent magnets compared to the typical machine. In addition, the thickness of the machine rotor disc has been reduced by optimizing the machine, which both enhances the power density and reduces the volume of the machine. Finally, the rotor-stator magnetic pulling force of the machine is simulated and analyzed, and the results prove that the proposed machine can operate stably.
Li, TaoWang, BitanDiao, ChengwuZhao, Wenliang
Current work details the preliminary CFD analysis performed on custom-built race car by Team Sakthi Racing team as part of Formula SAE competition using OpenFOAM. The body of the race car is designed in compliance with FSAE regulations, OpenFOAM utilities and solvers are used to generate volumetric mesh and perform CFD analysis. Formula student tracks are typically designed with numerous sharp turns and a few long straights to maintain low speeds for safety. In order to enhance the cars’ performance in sharp turns, the race car should be equipped with aerodynamic devices like nose cone and wings on both the rear and front ends within the confines of the formula student racing rules. Thus, efficient aerodynamic design is highly critical to maximizing tire grip by ensuring consistent contact with the track, reducing the risk of skidding, and maintaining control, especially during high-speed maneuvers. In this work, the performance and behavior of the race car, both with and without the
Rangarajan, KishorePushpananthan, BlesscinAnumolu, LakshmanSelvakumar, KumareshJayakumar, Shyam Sundar
This AIR provides commonly used design considerations for using composite component parts as secondary structures in landing gear applications.
A-5B Gears, Struts and Couplings Committee
From biology, to genetics, and paleontology, these fields share the DNA as a common and time-proven tool. In science, pressure may be such a tool, shared by thermodynamics, material science, and astrophysics, but not by aerodynamics. Pressure is a shorthand for a force acting perpendicular to a surface. When this surface is reduced to zero, so should the pressure. The wing area of an aircraft acts as a reference area to calculate its parasite drag coefficient. In this scenario, the parasite drag acts as a force over the wing area. If the wing area is reduced to zero, its parasite drag does not, as the fuselage is still generating parasite drag. The ratio of the parasite drag and wing area is an example of a pressure construct that uses a physically irrelevant reference area and has no absolute zero. Pressure constructs, more frequently used than pressures in aerodynamics, are a math-based parameter that preserve dimensional propriety according to the Buckingham Pi theorem but lacks a
Burgers, Phillip
The aerodynamic force produced by external flows over two-dimensional bodies is typically decomposed into two components: lift and drag. In race cars, the lift is known as downforce and it is responsible for increasing tire grip, thereby enhancing traction and cornering ability. Drag acts in the direction opposite to the car’s motion, reducing its acceleration and top speed. The primary challenge for aerodynamicists is to design a vehicle capable of producing high downforce with low drag. This study aims to optimize the shape of a multi-element rear wing profile of a Formula 1 car, achieving an optimal configuration under specific prescribed conditions. The scope of this work was limited to a 2-D model of a rear wing composed of two 4-digit NACA airfoils. Ten control parameters were used in the optimization process: three to describe each isolated profile, two to describe their relative position, and two to describe the angles of attack of each profile. An optimization cycle by finite
Souza Dourado, GuilhermeHayashi, Marcelo Tanaka
The purpose of this study is to analyze different airfoils using various tools like X-Foil and Reynolds-averaged Navier–Stokes (RANS) computational fluid dynamic (CFD) analysis (ANSYS Fluent) and compare both the results with wind tunnel experimental data to choose an aerodynamically efficient airfoil, which is suitable for an unmanned aerial vehicle/micro aerial vehicle (UAV/MAV) and its operational domain of Reynolds number. The main objective of this analysis is to identify and give us an understanding of the airfoil that has a higher value of Cl max and minimum possible value of Cd. This article discusses various low Reynolds number airfoils, i.e., for the range of Reynolds number between 50,000 and 200,000, which is mostly used for MAVs. Also, between the range of 100,000 and 200,000 for UAVs, which have displayed considerable performance in the past. The article also presents an effort to understand the phenomenon of laminar separation bubbles.
Roy, IndranilRao, Sameera
In this paper, a comprehensive analysis of NVH in electric powertrains due to electromagnetic sources is presented. The spatial harmonics model of the traction motor, which is dependent on the motor design structure, rotor poles, stator teeth, and slots, is used for the analysis of the electromagnetic forces from the motor in the electric powertrain. The time harmonics model of the injected current of the motor dependent on the drive electrical circuit and control strategy is also considered for the electromagnetic force calculation. A complete workflow of this electromagnetic NVH analysis for electric powertrain covering the spatial harmonics and time harmonics model is presented. The spatial harmonics model result is presented as flux linkage with respect to dq-axes current and rotor position. The time harmonics are also presented by the injected current of the motor. In addition, a set of operating points on the torque-speed boundary of the traction motor is selected and results are
Joshi, NakulKumar, VinitTsoulfaidis, AntoniosHuang, ZhenhuaSchmaedicke, MarcelFialek, GregoryZhang, DapuWimmer, Joe
Crawler Dozers play a critical role in global construction, mining and industrial sectors, performing essential tasks like pushing the material, grading, leveling and scraping. In the highly competitive dozer market, meeting the growing demand for increased productivity requires strategies to enhance blade capacity and width. Dozer operations involve pushing the material and dozing, where blade capacity significantly influences performance. Factors such as mold board profile, blade height, and width impact the blade capacity which are crucial for productivity in light weight applications such as snow removal and dirt pushing. Blade width is also pivotal for grading and leveling tasks. Traditional blade designs, like straight or fixed U-type blades, constrain operator flexibility, limiting overall productivity. The integration of hydraulic-operated foldable wings on both sides of the blade offers the adaptability to adjust blade capacity which also helps to reduce material spillage
Sahoo, Jyoti PrakashSarma, Neelam Kumar
This standard covers the requirements for non-separable, airframe antifriction needle bearings and corrosion-resistant and traditional materials intended for use in flight vehicle control systems with radial loads.
ACBG Rolling Element Bearing Committee
This document establishes a procedure for disposition of landing gear components that have been involved in accidents/incidents. The recommendations in this document apply to components made of ferrous and non-ferrous alloys. The recommendations in this document do not apply to components made of nonmetallic composite materials.
A-5B Gears, Struts and Couplings Committee
The objective of the paper is to enhance the aerodynamic performance of an aircraft wing using the injection–suction method. This method utilizes simulation techniques based on the Reynolds-averaged Navier–Stokes (RANS) equations with a k-epsilon turbulence model solver. The results of the simulations demonstrate a significant improvement in the wing’s performance, with a 33% increase in the stalling angle and a 10% enhancement in the lift coefficient compared to the baseline airfoil. The drag value is decreasing up to 40% depending on the angle of attack. The novelty of this proposed method was in the strategic placement of injection and suction. Injection is applied over the top airfoil at the separation point, while suction is applied at the midsection of the bottom airfoil. This configuration optimizes the aerodynamic flow over the wing, leading to improved performance metrics of lift coefficient and stall angle. This concept has potential applications in subsonic fixed-wing
Rameshbhai, Patel AnkitkumarPatidar, Vijay KumarBalaji, K.
As part of a larger research program on behalf of Transport Canada and the Federal Aviation Administration, APS Aviation Inc. conducted a series of representative scaled tests in the National Research Council Canada 3 m × 6 m Icing Wind Tunnel evaluating contaminated fluid flow-off from a common research model vertical stabilizer. The goal of this work is to help understand the impact of de/anti-icing fluids with and without precipitation on the performance of vertical surfaces, using existing allowance times that were developed for horizontal surfaces to guide the test exposure times. The data include a qualitative analysis of the appearance of the surfaces and a quantitative evaluation using aerodynamic data from an external balance and manual measurements of the fluid thicknesses on the model surface. The model was evaluated in a clean and dry configuration to establish the baseline aerodynamic performance, with sandpaper roughness testing used to as a substitute for fluids in order
Ruggi, MarcoClark, Catherine
Rotor and Stator are the key constituents of an electric motor that are made of several laminates punched from a sheet metal and stacked together. The rotor stack is inserted with magnets at the punched-out pockets and is assembled with a shaft via press fitting. Rotor assembly being the rotating part of an E-Motor is subjected to centrifugal loads due to masses of magnets, lamination stack and shaft rotating at high speeds, temperatures and assembling loads because of which rotor laminates experience failures as the high strains develop in the regions on the laminate that support magnets. Typically, these high strain locations are the sections of the magnet pockets one on the outer diameter of the laminate and the other at the sections between the magnet pockets. Traditionally, these high strains are addressed by increasing the area of these sections, but this has a detrimental effect on the electromagnetic performance. Instead of increasing the area of these sections, the proposed
Pawde, DeepakSrimathkandala, MaithiliGalande, Pandurang
This SAE Aerospace Recommended Practice establishes the requirements and procedures for eddy current inspection of open fastener holes in aluminum aircraft structures.
AMS K Non Destructive Methods and Processes Committee
This document provides the specifications of horizontal hard-bearing balancing machines, which make such machines suitable for gas turbine rotor balancing.
EG-1A Balancing Committee
Brake squeal is a phenomenon caused by various factors such as stiffness of brake components, mode coupling, friction coefficient, friction force variation, pressure, temperature and humidity. FEA simulation is effective at predicting and investigating the cause of brake squeal, and is widely used. However, in many FEA simulations, models of brake lining are mostly a brand-new shaper, so that the change of pressure distribution or pad shape, which can occur due to the lining wear, are not taken account. In this research, brake squeal analysis was conducted with consideration of lining wear, applying Fortran codes for Abaqus user subroutine. The brake assembly model for the analysis is created by using a 3D scanner and has a close shape to the real one. The wear patterns calculated by the analysis are similar to those of brake pads after a noise test. The complex eigenvalue analysis shows two unstable modes at the frequency of squeal occurred in the noise test. One is out-of-plane
Ikegami, TokunosukeMillsap, TomYamaguchi, Yoshiyuki
This article aims to conduct a comprehensive performance analysis of various propeller configurations and motors for uncrewed aerial vehicles. The experimental method is used for this study through the performance analysis of the motors and propellers at various conditions. In this study, the test rig has been manufactured specially to test the propeller and motor configuration as per the standard to obtain the thrust at various supplied voltage. This study proved that the increase in the size of propeller leads to increase in the thrust, as well as it can be used for specific applications of the drone like racing drone. It reveals that the maximum diameter of a propeller is 14 inches, which produces the thrust in the range of 2400 g to 361 g depending on motor capacity compared to the other size of the propellers. The novelty of the work is to analyze the performance of propellers and motors for optimization and application of drones through experimental methods. This method can be
Ajay Vishwath, N.C.Balaji, K.Vaishampayan, VibhavPatil, DeepMehta, ParshvaDonde, Gaurangi
There are examples in aerodynamics that take advantage of electric-to-aerodynamic analogies, like the law of Biot–Savart, which is used in aerodynamic theory to calculate the velocity induced by a vortex line. This article introduces an electric-to-aerodynamic analogy that models the lift, drag, and thrust of an airplane, a helicopter, a propeller, and a flapping bird. This model is intended to complement the recently published aerodynamic equation of state for lift, drag, and thrust of an engineered or a biological flyer by means of an analogy between this equation and Ohm’s law. This model, as well as the aerodynamic equation of state, are both intended to include the familiar and time-proven parameters of pressure, work, and energy, analytical tools that are ubiquitous in all fields of science but absent in an aerodynamicists’ day-to-day tasks. Illustrated by various examples, this modeling approach, as treated in this article, is limited to subsonic flight.
Burgers, Phillip
Semi-automated computational design methods involving physics-based simulation, optimization, machine learning, and generative artificial intelligence (AI) already allow greatly enhanced performance alongside reduced cost in both design and manufacturing. As we progress, developments in user interfaces, AI integration, and automation of workflows will increasingly reduce the human inputs required to achieve this. With this, engineering teams must change their mindset from designing products to specifying requirements, focusing their efforts on testing and analysis to provide accurate specifications. Generative Design in Aerospace and Automotive Structures discusses generative design in its broadest sense, including the challenges and recommendations regarding multi-stage optimizations. Click here to access the full SAE EDGETM Research Report portfolio.
Muelaner, Jody Emlyn
With the automotive industry’s increasing focus on electromobility and the growing share of electric cars, new challenges are arising for the development of electric motors. The requirements for torque and power of traction motors are constantly growing, while installation space, costs and weight are increasingly becoming limiting factors. Moreover, there is an inherent conflict in the design between power density and efficiency of an electric motor. Thus, a main focus in today’s development lies on space-saving and yet effective and innovative cooling systems. This paper presents an approach for a multi-physical optimization that combines the domains of electromagnetics and thermodynamics. Based on a reference machine, this simulative study examins a total of nine different stator cooling concepts varying the cooling duct positions and end-winding cooling concepts. To ensure the highest possible comparability, the rotor geometry as well as the overall dimensions in terms of outer
Reinecke, MikeKarayel, Akifvon Schöning, HendrikSchaefer, UweMoullion, MatthiasFaessler, VictorLehmann, Robert
This SAE Aerospace Recommended Practice (ARP) recommends the maintainability features that should be considered in the design of aircraft wheels and brakes. The effect on other factors, such as cost, weight, reliability, and compatibility with other systems, should be weighed before incorporation of any of these maintainability features into the design.
A-5A Wheels, Brakes and Skid Controls Committee
This document defines the criteria used for the selection and placement of landing gear shock strut upper and lower bearings (see Figure 1). Common problems associated with shock strut bearings are presented herein.
A-5B Gears, Struts and Couplings Committee
This document outlines the most common repairs used on landing gear components. It is not the intention of this AIR to replace overhaul/component maintenance or technical order manuals, but it can serve as a guide into their preparation. Refer to the applicable component drawings and specifications for surface finish, thickness, and repair processing requirements. This document may also be used as a guide to develop an MRB (Material Review Board) plan. The repairs in this document apply to components made of metallic alloys. These repairs are intended for new manufactured components and overhauled components, including original equipment manufacturer (OEM)/depot and in-service repairs. The extent of repair allowed for new components as opposed to in-service components is left to the cognizant engineering authorities. Reference could be made to this document when justifying repairs on landing gears. For repairs outside the scope of this document, a detailed justification is necessary
A-5B Gears, Struts and Couplings Committee
The intent of this AIR is twofold: (1) to present descriptive summary of aircraft nosewheel steering and centering systems, and (2) to provide a discussion of problems encountered and “lessons learned” by various airplane manufacturers and users. This document covers both military aircraft (land-based and ship-based) and commercial aircraft. It is intended that the document be continually updated as new aircraft and/or new “lessons learned” become available.
A-5B Gears, Struts and Couplings Committee
With regards to any aerospace mission, it is very useful to have awareness about the state of vehicle, i.e., the information about its position, velocity, attitude, rotational rates and other concerned data such as control surface deflections, landing gear touchdown, working of mechanisms and so on. The sensor data from the vehicle that is communicated to the ground can be difficult to perceive and analyze. A frame work for real-time motion simulation of an aerospace vehicle from onboard telemetry data is henceforth developed in order to improve the understanding about the current state of the mission and aid in real-time decision making if required. The telemetry data, that is transmitted through User Datagram Protocol (UDP), is received and decoded to usable format. The visualization software accepts the data in a fixed time interval and applies the required transformations in order to ensure one-to-one correspondence between actual vehicle and simulation. The transformations
Shaw, Sandeep PrasadThakur, AdarshNair, TharaKK, Raveendra
The mystery of how futuristic aircraft embedded engines, featuring an energy-conserving arrangement, make noise has been solved by researchers at the University of Bristol. University of Bristol, Bristol, UK A study published in Journal of Fluid Mechanics, reveals for the first time how noise is generated and propagated from these engines, technically known as boundary layer ingesting (BLI) ducted fans. BLI ducted fans are similar to the large engines found in modern airplanes but are partially embedded into the plane's main body instead of under the wings. As they ingest air from both the front and from the surface of the airframe, they don't have to work as hard to move the plane, so it burns less fuel. The research, led by Dr. Feroz Ahmed from Bristol's School of Civil, Aerospace and Design Engineering under the supervision of Professor Mahdi Azarpeyvand, utilized the University National Aeroacoustic Wind Tunnel Facility. They were able to identify distinct noise sources originating
The design of aerospace applications necessities precise predictions of aerodynamic properties, often obtained through resource-intensive numerical simulations. These simulations, though they are accurate, but are unsuitable for iterative design processes due to their computational complexity and time-consuming nature. To address this challenge, machine learning, with its data-driven approach and advanced algorithms, offers a novel and cost-effective solution for predicting airfoil characteristics with exceptional precision and speed. This study explores the application of the Back-Propagation Neural Network (BPNN), a machine learning model, to forecast critical aerodynamic coefficients such as lift and drag for airfoils. The BPNN model is fed with input parameters including the airfoils name, flow Reynolds number, and angle of attack in relation to incoming flows. Training the BPNN model is accomplished using a dataset derived from CFD simulations employing the Spalart–Allmaras
M N, LochanN, RakshithaPrasad, B K SwathiSivasubramanian, Jayahar
Thin cylindrical shells are ubiquitous structural elements in aerospace structures, and they experience catastrophic buckling under axial compression. The recent advancements in theoretical and numerical studies aided in realising the role of localisation in shell buckling. However, the instantaneous buckling made it unfeasible for the experimental observations to corroborate the numerical results. This necessitates high-fidelity shell buckling experiments using full-filed measurement techniques. Cutouts are deliberate and inevitable geometrical imperfections in actual structures that could dictate the buckling response. Additive manufacturing makes fabricating shells with tailored imperfections and studying various conceivable designs feasible. Consequently, to comprehend the effect of circular cutout on the buckling response, cylindrical shells are 3D printed in thermoplastic polyurethane (TPU) with a circular cutout of a specific size that could significantly shorten the buckling
Ravulapalli, VineethRaju, GangadharanManoharan, RamjiNaryanamurthy, Vijayabaskar
Dimensional optimization has always been a time-consuming process, especially for aerodynamic bodies, requiring much tuning of dimensions and testing for each sample. Aerodynamic auxiliaries, especially wings, are design dependent on the primary model attached, as they influence the amount of lift or reduction in drag which is beneficial to the model. This study aims to reduce the time period taken to finalize the design parameter for the same. For a wing, the angle of attack is essential in creating proper splits to incoming winds, even under high velocities with larger distances from the separation point. In the case of a group of wings, each wing is then mentioned as a wing element, and each wing is strategically positioned behind the previous wing in terms of its vertical height and its self-angle of attack to create maximum lift. At the same time, its drag remains variable to its shape ultimately maximizing the CL/CD ratio. A high value of CL indicates a significant component of
Hujare, Pravin PHujare, Deepak PChoudhary, PrateekSakat, AbhishekKaranjkar, Rushil
A study published in Journal of Fluid Mechanics, reveals for the first time how noise is generated and propagated from these engines, technically known as boundary layer ingesting (BLI) ducted fans. BLI ducted fans are similar to the large engines found in modern airplanes but are partially embedded into the plane’s main body instead of under the wings. As they ingest air from both the front and from the surface of the airframe, they don’t have to work as hard to move the plane, so it burns less fuel.
A lightweight high-pressure hose assembly consists of hose made with fabric braids and PTFE (Polytetrafluoroethylene) tube crimped with metallic fittings. These hose assemblies are mainly used for aircraft landing gear application considering its high-pressure sustenance and better flexibility. The proposed study investigates the effect of thermo-mechanical stresses generated during cyclic soaking and flexibility testing at thermostatic subzero (-65°F) and high temperature (+275°F) on performance of high pressure- fabric braided hose assembly. This effect was further studied through hose tear-down to investigate the hose layer degradation and focused changes in inner PTFE tube. With an incremental exposure to cyclic temperature environment, a linear growth was observed for the micropores within PTFE.
Neve, AbhilashPatil, Sandip
This document outlines the development process and makes recommendations for total antiskid/aircraft systems compatibility. These recommendations encompass all aircraft systems that may affect antiskid brake control and performance. It focuses on recommended practices specific to antiskid and its integration with the aircraft, as opposed to more generic practices recommended for all aircraft systems and components. It defers to the documents listed in Section 2 for generic aerospace best practices and requirements. The documents listed below are the major drivers in antiskid/aircraft integration: 1 ARP4754 2 ARP4761 3 RTCA DO-178 4 RTCA DO-254 5 RTCA DO-160 6 ARP490 7 ARP1383 8 ARP1598 In addition, it covers design and operational goals, general theory, and functions, which should be considered by the aircraft brake system engineer to attain the most effective skid control performance, as well as methods of determining and evaluating antiskid system performance. For definitions of
A-5A Wheels, Brakes and Skid Controls Committee
This SAE Aerospace Information Report (AIR) describes the design approaches used for current applications of aircraft Brake-by-Wire (BBW) control systems. The document also discusses the experience gained during service, and covers system, ergonomic, hardware, and development aspects. The document includes the lessons that have been learned during application of the technology. Although there are a variety of approaches that have been used in the design of BBW systems, the main focus of this document is on the current state of the art systems.
A-5A Wheels, Brakes and Skid Controls Committee
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