Browse Topic: Aircraft structures

Items (3,676)
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
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
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
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 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
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
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 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
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 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
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
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
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
This document presents a study on the design and simulation of a high-lift airfoil intended for usage in multielement setups such as the wings present on open-wheel race cars. With the advancement of open-wheel race car aerodynamics, the design of existing high-lift airfoils has been altered to create a more useful and practical general profile. Adjoint optimization tools in CFD (ANSYS Fluent) were employed to increase the airfoil’s performance beyond existing high-lift profiles (Selig S1223). Improvements of up to 20% with a CL of 2.4 were recorded. To further evaluate performance, the airfoil was made the basis of a full three-dimensional aerodynamics package design for an open-wheel Formula Student car. CFD simulations were carried out on the same and revealed performance characteristics of the airfoil in a more practical application. These CFD simulations were calibrated with experimental values from coast-down testing data with an accuracy of 8
Karthikeyan, Prthik NandhanRadhakrishnan, Jayakrishnan
This SAE Aerospace Recommended Practice (ARP) defines the performance criteria and validation for tire circumferential movement on the rim, in the laboratory, by a static test, as well as a performance assessment in service. This document is applicable to braked wheel positions using both bias ply and radial aircraft tires
A-5C Aircraft Tires Committee
This SAE Aerospace Standard (AS) sets forth criteria for the selection and verification processes to be followed in providing tires that will be suitable for intended use on civil aircraft. This document encompasses new and requalified radial and bias aircraft tires
A-5C Aircraft Tires Committee
This document describes a recommended test procedure to assess the burst characteristics of tires used on 14CFR Part 25 or similar transport airplanes
A-5C Aircraft Tires Committee
In the process of designing the aerodynamic kit for Formula SAE racing cars, there is a lot of repetitive work and low efficiency in optimizing parameters such as wing angle of attack and chord length. Moreover, the optimization of these parameters in past designs heavily relied on design experience and it's difficult to achieve the optimal solution through theoretical calculations. By establishing a parametric model in CAD software and integrating it with CFD software, we can automatically modify model parameters, run a large number of simulations, and analyze the simulation results using statistical methods. After multiple iterations, we achieve fully automatic parameter optimization and obtain higher negative lift. At the same time, the simulation process is optimized, and simulations are run based on GPUs, resulting in a significant increase in simulation speed compared to the original. The results show that automated optimization saves a lot of manpower costs, and compared to
Chen, Yanjun
In electric vehicle applications, the majority of the traction motors can be categorized as Permanent Magnet (PM) motors due to their outstanding performance. As indicated in the name, there are strong permanent magnets used inside the rotor of the motor, which interacts with the stator and causes strong magnetic pulling force during the assembly process. How to estimate this magnetic pulling force can be critical for manufacturing safety and efficiency. In this paper, a full 3D magnetostatic model has been proposed to calculate the baseline force using a dummy non-slotted cylinder stator and a simplified rotor for less meshing elements. Then, the full 360 deg model is simplified to a half-pole model based on motor symmetry to save the simulation time from 2 days to 2 hours. A rotor position sweep was conducted to find the maximum pulling force position. The result shows that the max pulling force happens when the rotor is 1% overlapping with the stator core. The impact of asymmetric
Gong, ChengChang, LeHe, SongZhang, PengMuir, Michael
The rotor and stator of electric motors consist of multiple materials, of which steel forms the majority of mass and volume. Steel in electric motors is commonly in the form of thin sheets (laminations), stacked along the axis of the rotor. The structural integrity of such a stack can be ensured using bolting, welding or bonding of the laminations. Predictive mechanical finite element simulations of these laminated stacks can become computationally intense because the steel sheets are thin, and the motor often contains hundreds of them. If the laminations are modelled individually, the size of the elements is very small compared to the overall dimensions and the interface between the laminations need to be modelled as well. In this paper, we present an alternate method of modelling this laminated stack as a single solid body using homogeneous and orthotropic material property, instead of representing each lamination. This provides realistic predictions of mechanical performance, while
Goel, AshishP, PraveenSharma, HirenFaggioli, Thiago
Wound rotor synchronous machines (WRSM) without rare-earth magnets are becoming more popular for traction applications, but their potential in drive performance has not yet been fully explored. This paper presents a Pulse Width Modulation (PWM) scheme optimization procedure to minimize motor and inverter losses. It leverages different PWM schemes with different PWM switching strategies and switching frequencies. First, a generic PWM-induced motor loss calculation tool developed by BorgWarner is introduced. This tool iteratively calculates motor losses with PWM inputs across the entire operating map, significantly improving motor loss prediction accuracy. The inverter losses are then calculated analytically using motor and wide-bandgap (WBG) switching device characteristics. By quantifying these various scenarios, the optimal PWM scheme for achieving the best system efficiency across the entire operating map is obtained. The PWM-induced motor loss characteristics, the system loss
Ma, CongTyckowski, Joseph
When the aircraft towing operations are carried out in narrow areas such as the hangars or parking aprons, it has a high safety risk for aircraft that the wingtips may collide with the surrounding aircraft or the airport facility. A real-time trajectory prediction method for the towbarless aircraft taxiing system (TLATS) is proposed to evaluate the collision risk based on image recognition. The Yolov7 module is utilized to detect objects and extract the corresponding features. By obtaining information about the configuration of the airplane wing and obstacles in a narrow region, a Long Short-Term Memory (LSTM) encoder-decoder model is utilized to predict future motion trends. In addition, a video dataset containing the motions of various airplane wings in real traction scenarios is constructed for training and testing. Compared with the conventional methods, the proposed method combines image recognition and trajectory prediction methods to describe the relative positional relationship
Zhu, HengjiaXu, YitongXu, ZiShuoJiYuan, LiuZhang, Wei
The modern luxurious electric vehicle (EV) demands high torque and high-speed requirements with increased range. Fulfilling these requirements gives rise to the need for increased efficiency and power density of the motors in the Electric Drive Unit (EDU). Internal Permanent Magnet (IPM) motor is one of the best suited options in such scenarios because of its primary advantages of higher efficiency and precise control over torque and speed. In the IPM motor, permanent magnets are mounted within the rotor body to produce a resultant rotating magnetic field with the 3-phase AC current supply in the stator. IPM configuration provides structural integrity and high dynamic performance as the magnets are inserted within the rotor body. Adhesive glue is used to install the magnets within the laminated stack of rotor. High rotational speed of rotor introduces centrifugal loading on the magnets which can result in multiple failure modes such as the debonding of the magnet, and high radial
Karmakar, NilankanP, PraveenGoel, Ashish
This article presents a method for improving electric motor noise and vibration analysis based on rotor load. The method first obtains two key parameters, namely the characteristics of the stator and rotor core material and the connection stiffness between the rotor skewed poles, through modal testing and simulation calibration of the stator and rotor. Subsequently, the electromagnetic simulation is used to calculate the torque fluctuation of each segment of the rotor skewed poles, which is used as input load for the structural simulation. The vibration of the suspension point and the radiation noise of the transmission housing are then calculated under the action of torque fluctuation. The study highlights the significant contribution of the rotor torsional mode to noise and vibration. Finally, by improving the torsional stiffness of the rotor and the distribution of skewed poles, the noise and vibration problems caused by torsional mode can be significantly improved, leading to
Zhang, JingwenGeng, ZhirongLi, QiangLi, Shuangchi
This document contains the recommended practices for the traceability of civil aircraft life-limited parts (LLPs) applicable to landing gears. A unified means of tracking flight cycles, flight hours, and calendar time is provided, which will ease the interchange of parts between companies and through the component’s life cycle. A harmonized means of defining “back-to-birth” (BtB) traceability is provided to ensure airworthiness of service LLPs
A-5B Gears, Struts and Couplings Committee
Additive manufacturing (AM) is currently the most sought-after production process for any complex shaped geometries commonly encountered in Aerospace Industries. Although, several technologies of AM do exits, the most popular one is the Direct Metal Laser Sintering (DMLS) owing to its high versatility in terms of precision of geometries of components and guarantee of highest levels of reduction in production time. Further, metallic component of any complex shape such as Gas Turbine Blades can also be developed by this technique. In the light of the above, the present work focuses on development of iron silicon carbide (Fe-SiC) complex part for ball screw assembly using DMLS technique. The optimized process parameters, hardness and wear resistance of the developed iron-SiC composite will be reported. Further, since the material chosen is a metallic composite one, the effect of SiC on the thermal stresses generated during the DMLS processing of Fe-SiC composite will also be discussed. A
Chinnakurli Suryanarayana, RameshCheekur Krishnamurthy, SrinivasaH, AdarshaMukunda, Sandeep
Aircraft moving at transonic speeds (i.e., ~0.7 to 0.85 Mach - or near the speed of sound) experience transonic wing flutter. Engineers have traditionally relied on experimental or computational methods to understand wing flutter for the design process. Modeling wing flutter using the customary computational methods requires tens of hours of simulations on a supercomputer that is costly to buy or rent. Having a method to model wing flutter aerodynamics without requiring supercomputer use would (a) increase the efficiency and decrease the cost of aircraft wing design and (b) enable real-time wing-flutter modeling to aid in-flight aircraft operation and control
This SAE Aerospace Recommended Practice (ARP) identifies the best practices to reduce damage and promote safety during the storage, handling, and shipping of W/T assemblies
A-5 Aerospace Landing Gear Systems Committee
The ground vibration test (GVT) is an important phase in a new aircraft development program, or the structural modification of a certified aircraft, to experimentally determine the structural vibrational modes of the aircraft and their modal parameters. These modal parameters are used to validate and correlate the dynamic finite element model of the aircraft to predict potential structural instabilities (such as flutter), assessing the significance of modifications to research vehicles by comparing the modal data before and after the modification and helping to resolve in-flight anomalies. Due to the high cost and the extensive preparations of such tests, a new method of vibration testing called the taxi vibration test (TVT) rooted in operational modal analysis (OMA) was recently proposed and investigated as an alternative method to conventional GVT. In this investigation, an experimental setup was constructed to further investigate the applicability of the TVT to flexible airframes
Al-bess, LohayKhouli, Fidel
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