Browse Topic: Aircraft structures

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This AIR provides a general guideline on how to perform effective measurement systems analysis study (MSA) for rotor balancing tasks. The document also includes applicable data analysis methods and result interpretation.
EG-1A Balancing Committee
With the recent renewed interest in manned lunar exploration, it is critical to revisit the Apollo Moon landings with new analysis tools. Modeling the Moon landings of the past can help guide the development of new landing vehicles for the present and the future. One of the critical subsystems to model is the vehicle’s landing gear. During a landing event, structural loading, energy absorption, and toppling stability are important factors that drive the design of landing gear subsystems. These aspects can be studied using models and simulations in addition to physical testing. This study explores one recent modeling tool for modeling the landing gear and uses the Apollo 11 Moon landing as a use case. A generic model was built using MATLAB®, Simulink®, and Simscape® Multibody to model the dynamics of a landing event. The landing gear structure comprising the primary strut, secondary struts, footpads, and joints was modeled in Simscape® Multibody. Various energy absorption mechanisms in
Arndt, GrantWu, WeiButzman, Noah
Individuals who complete the applicable modules aligned with this training document will be able to define the type of damage, define the extent of damage, determine if further inspection is required, evaluate the damage against published allowable damage limits, and provide accurate documentation of the damage. The intended outcome of the training is increased safety such that no aircraft is released with unknown damage and that the aircraft meets continued airworthiness requirements. The goal is to change the culture from damage discovery to damage reporting while also reducing or eliminating flight delays due to incorrect or insufficient information. Teaching levels have been assigned to the curriculum to define the knowledge, skills, and abilities graduates will need. Minimum hours of instruction have been provided to ensure adequate coverage of all subject matter including lecture and practical exercise. These minimums may be exceeded and may include an increase in the total
AMS CACRC Commercial Aircraft Composite Repair Committee
Hydrogen-fueled rotary engines offer a promising zero-emission solution for compact commercial powertrains. This study reports experimental results from the further development of a naturally aspirated, direct-injection hydrogen rotary engine by HTM. Initial applications, such as an airport baggage tractor, demonstrated technical feasibility but revealed pre-ignition that limited maximum torque. To address this, mixture formation was investigated using an experimental setup with two independently controlled injectors feeding a single rotor injection channel. The effects on operating behavior, efficiency, and NOx emissions were evaluated. The dual-injector configuration significantly shortens injection duration and improves spatial distribution of hydrogen within the combustion chamber. Enhanced mixture control suppresses pre-ignition and enables higher mean effective pressure. Systematic variation of injection timing under representative steady-state conditions also shows potential for
Endres, JonasBeidl, ChristianHerold, TimLavall, PhilippSchmidt, MarvinHofmann, SilasKahl, Jonas
The paper presents a method for enhancing the static pressure calibration of a high-performance aircraft. Despite the pre-flight calibration using CFD and Wind Tunnel techniques, position errors are generally observed in the free stream parameters, which necessitate further calibration of air data sensors using flight test data. In the present research, the pressure coefficient is estimated as a time-varying parameter in the flight path reconstruction environment implemented using the Extended Kalman Filtering technique. Aircraft kinematic equations were used for the implementation of the state and measurement models, and flight test data from full flight sorties were used in the estimation process. An extensive validation of the on-board air data calibration tables was conducted. Mean values of the static pressure coefficient were updated using data from multiple sorties, each including computed mean errors from three independent sensors. A comparative analysis between the pre
TK, Khadeeja NusrathPatel, Dr. Ambalal VJ, Prabhavathi Bhai
Launch vehicle structures are designed to withstand flight loads while fulfilling their intended functional requirements. Most of these structures use cylindrical geometries and employ stiffened configurations—such as isogrid, orthogrid, or skin-stiffened designs—comprising multiple long panels to efficiently carry dominant compressive loads. Traditional FE analyses generally use simplified or idealized imperfection models, which often do not represent the imperfections present in actual hardware and therefore tend to over/under-predict load-carrying capacity based on the initial assumed imperfection level. In reality, long stiffened panels are highly sensitive to geometric imperfections introduced during manufacturing. These include spring-back effects from roll bending as well as deviations accumulated during assembly. Such manufacturing-induced variations can significantly diminish the effective load-bearing capability of the structure. The subject hardware—an isogrid cylindrical
Sharma, AmitSingh, NishantXavier, ShijoR, Suresh
This study presents a comprehensive methodology for optimizing critical UAV structural nodes—specifically Arm Clamps, Landing Gear, and Motor Mounts—using Generative Design (GD) tailored for Fused Filament Fabrication (FFF) with PLA+. Traditional “plate-and-standoff” UAV constructions often utilize orthogonal geometries that induce stress concentrations and fail to leverage the geometric freedom of additive manufacturing. Furthermore, reliance on expensive CNC machining or injection molding creates supply chain bottlenecks for custom or short-run UAV production. While FFF offers geometric freedom, applying it to structural airframe parts introduces challenges regarding anisotropy, layer adhesion, and material brittleness. This research optimizes these components for standard commercial 3D printers by strictly enforcing manufacturing constraints, including a 40-degree maximum overhang and a 0.4 mm nozzle size, to ensure printability without internal support structures. A significant
Krishna Bansal, Vaibhav
Acoustic-induced vibrations pose a significant risk to launch vehicle hardware and payload reliability during critical phases such as lift-off and transonic phase. Reducing such vibrations is especially challenging when the hardware has already been fabricated, limiting the possibility of structural redesign. This study demonstrates a practical post-fabrication solution using a thin viscoelastic polymer coating applied externally to fully assembled hardware. Comprehensive evaluations were conducted using both acoustic testing and Experimental Modal Analysis (EMA) before and after coating application. During acoustic test, a substantial decrease in structure response from 150Hz to 2000Hz, with a reduction of approximately 50% in the grms values was observed for the coated structure demonstrating significant vibration mitigation over a wide frequency range. In contrast, EMA measurements using impact excitation revealed that the response transfer functions did not show a significant
Avirah, Nohin KPanda, Ajay KumarShaikh, Altafhusen
Digital engineering practices in aerospace increasingly require closely connected and traceable analysis workflows rather than isolated finite element tasks. Traditional FEA methods remain effective, but they involve considerable manual effort during pre- processing and post-processing, making rapid iteration difficult. Finite Element Analysis of STructures (FEAST), an indigenous finite element analysis software developed by Vikram Sarabhai Space Centre (VSSC) ISRO, offers structural analysis capabilities through a command-based architecture, yet its manual operation limits its use in automated studies. This work develops a flexible scripting-driven framework that links geometry creation, load-case definition, solver execution, and result interpretation within a unified digital engineering pipeline. The framework automates repetitive tasks, incorporates Design of Experiments (DoE) for systematic parameter variation, and supports sensitivity and automation studies. Its performance is
Gupta, ShivangiT J, Raj ThilakP, Deepak
This SAE Aerospace Recommended Practice (ARP) establishes the overall component and system function guidelines and minimum performance levels for a TPMS. These guidelines include, but are not limited to: Design recommendations for system components, which: Monitor tire inflation Are located in/on the tire/wheel assembly, landing gear axle, and/or aircraft avionics compartment Recommended performance and safety guidelines for a TPMS.
A-5 Aerospace Landing Gear Systems Committee
This study systematically evaluated the wear resilient performance of AZ61 magnesium alloy reinforced with 15 wt.% SiC and diverse amounts of multi-walled carbon nanotubes (MWCNTs) under dry sliding circumstances adopting pin-on-disc apparatus (ASTM G99). To identify the influence of factors like sliding speed (SS) (1-3 m/s), axial load (AL) (10-30 N), and MWCNT concentration (0-3 wt.%) that affect tribological performance, experiments were developed using a Central Composite Design (CCD) under Response Surface Methodology (RSM). SEM micrographs revealed a dispersion optimum near 2 wt.% MWCNT, where CNTs anchor to SiC and bridge the α-Mg matrix, while 3 wt.% shows agglomerates and micro-voids. Findings showed that wear loss (WL) and friction coefficient (CoF) was greatly amplified by increasing AL owing to localized heating and contact stresses. A compacted tribolayer was formed by increasing SS, which decreased WL but marginally raised the CoF. At low AL (10 N), SS (2.09 m/s), and
Senthilkumar, N.
Initial weight estimation from Top Level Aircraft Requirements (TLAR) is a critical first step in aircraft design, yet existing empirical methods are inadequate for novel configurations such as those using Liquid Hydrogen (LH2) or Sustainable Aviation Fuels (SAF). This paper presents a hybrid methodology for top-level weight estimation of such unconventional aircraft. The approach is based on modifying a conventional baseline aircraft, integrating a new statistical model with component-specific weight estimations. A multivariate regression model to estimate the empty weight fraction (We/W0) was developed from a dataset of 44 conventional aircraft, yielding an R-squared value of 0.833. This statistical model was integrated with physics-based models for novel components, including cryogenic fuel tanks and fuel systems. The methodology accounts for iterative changes to fuselage structure and parasitic drag. Four configurations were analyzed: fuel types being Jet A1, SAF, LH2 with aft
Goyal, Tushar
Submarine-launched missiles with domed nose cones are highly vulnerable to cavitation erosion as they travel at high speed through an underwater launch tube and then into the air from the sea surface. The collapse of vapour cavities crystallizes intense damage on the vehicle surfaces so that the vehicle structure and aerodynamic performance are threatened. In this work, we show the full 3D numerical and analytical analysis of surface protection concepts for the reduction of cavitation damage on such an axisymmetric dome-shaped body. A computational methodology was developed by importing a complex computer-aided design (CAD) model of a dome and the connecting tubular structure into a high-fidelity simulation environment. The geometry was simplified by omitting non-essential details to facilitate the generation of quality mesh for CFD analysis. Simulations have been carried out to analyze the flow field and pressure distribution under two critical stages, at two angles of attack of 0
Velayudhan, GauthamP S, PremkumarS, Suhail AhmedP, KrishnakumarVasantharaj, C
As the trend toward larger wind turbines continues, the increasing length of blades imposes higher demands on their structural properties. And in actual engineering, wind turbine blade accidents occur frequently. Consequently, ultra-long flexible blades at the hundred-meter scale typically employ composite materials. However, due to the high cost of composites, it is necessary to minimize blade weight to control costs. This study utilizes the MATLAB simulation platform combined with pattern search algorithms to optimize the composite layup of large wind turbine blade structures. The structural properties of the optimized design are then compared and analyzed against those of the reference structure. Simultaneously investigate the impact of different loads on the optimization results. The results demonstrate that the pattern search algorithm can optimize blade layup thickness, spar chordwise position, and spar width, yielding a new blade structure with improved performance. During
Cao, GuangchuanGuo, XiaMeng, Hang
Cycloidal rotor pumps are widely used in industries such as automotive and aerospace due to their advantages of compact structure, large displacement per unit volume, and low flow pulsation. With the development of new energy vehicles, rotor pumps are required to operate stably for extended periods under higher speeds, higher pressures, and harsher conditions, placing greater demands on their reliability. Addressing the specific problem of fracture failure of the inner rotor in a certain cycloidal rotor pump during bench testing, this paper first conducted a theoretical analysis of the inner rotor's metallographic structure. The metallographic results indicated that the inner rotor fracture was unrelated to material quality but was instead caused by the improper positioning of the slot on the pump's inner rotor, making the slot root the weakest part of the entire rotor material. Furthermore, sharp corners existed on the inner slot surface, leading to significant stress concentration at
Li, MengXie, JIaQin, GongyuYang, HanmingWang, Liangmo
The front wing of a Formula 1 car is one of the most important aerodynamic components in design development. Particularly, as it is the first to interact with the upcoming airflow, the aerodynamic flow structures generated will have a strong interaction with the remainder of the car’s components. In 2026, the Fédération Internationale de l’Automobile will introduce new regulations that incorporate new aerodynamic philosophies for the front wing, including active aerodynamics. This paper presents a design methodology study for the development of a Formula 1 2026 front wing, compliant with Issue 9 of the technical regulations. A computational-based, structured optimisation series was conducted to enhance the aerodynamic performance of a front wing concept with a focus on improving downforce, maximising efficiency, and enhancing trailing flow for the remainder of the car. The final front wing concept at 40%, running at 30 m/s, generated 189 N of downforce and 19 N of drag. Active
Jacoulot, SantiagoSoares, Renan F.Marshall, David W.
Automotive turbochargers are carefully designed to avoid resonance of the turbine blades and backwall, which can result in High Cycle Fatigue failures. Blade Tip Timing is an established technique which utilizes fiber optic probes to measure turbine blade displacements in real time on turbochargers spinning at upwards of 150,000 RPM. Historically, Blade Tip Timing measurements of automotive turbochargers have been made under steady-state conditions using a Hot Gas Stand. In an industry first, General Motors conducted testing of a turbocharger on a running gasoline engine to capture realistic exhaust pressure dynamics. A reference turbocharger was measured on an engine testbed running a production calibration; the same turbocharger was then tested on a Hot Gas Stand to observe how the blade behavior changed. Blade displacements were found to be lower on engine, because the dynamics of engine pulsation reduced the in-phase work available to drive the turbine blades, resulting in lower
SCHWARZ, JORDANGoodheart, RachelTappert, PeterDePaoli, DominicLongacre, Christian
High thermal loads on brake systems during extended descents followed by vehicle soak pose significant safety and durability risks. Excessive rotor or fluid temperatures can cause loss of braking efficacy, fluid degradation or evaporation, thermal fade, and accelerated component wear. This study uses time-history data of brake-disc and fluid temperatures which were collected during controlled hill-descent events with subsequent soak periods, where the vehicle is parked in a wind protected area. Besides the rotor and brake fluid temperatures, environmental conditions were recorded (ambient temperature, humidity, wind speed and direction) and the vehicle and brake specifications are known (rotor/caliper geometry, pad material, vehicle aerodynamic configuration and mass). 126 test runs from a dedicated vehicle program are used, each providing time-history records that form the basis of our analysis. From these records we extract phase-specific samples (descent and soak phase) and engineer
Poojari, Uday KumarWestphalen, JanVenugopal, Narayana
This SAE Aerospace Information Report (AIR) discusses the potential considerations for landing gear that may have to traverse arresting cables. This can be a consideration for civil aircraft and aircraft without arresting hooks that operate into dual use (military and civil) airfields.
A-5B Gears, Struts and Couplings Committee
A research team developed a smart strake system that dynamically adapts to flight conditions, showing a promising drag reduction in the wind tunnel with respect to passive strakes. This approach has the potential to save airlines hundreds of kilograms of fuel per flight. University of Washington Department of Aeronautics & Astronautics (A&A), Seattle, WA For decades, aircraft have carried a fundamental compromise between their engines and wing flow interactions by using strakes. These are small fins attached at the sides of engine nacelles that generate helpful vortices during takeoff and landing that boost lift and avoid stall, but create unwanted drag during cruise flight. Now, seven William E. Boeing Department of Aeronautics & Astronautics (A&A) undergraduates have advanced a solution that improves this trade-off, achieving up to 33 percent drag reduction, on the limited tested conditions, during cruise while maintaining critical safety benefits at high angles of attack. The team
The purpose of this SAE Aerospace Information Report (AIR) is to present a sample of the range of tire chine designs approved for application on aircraft requiring non-standard water spray deflection.
A-5C Aircraft Tires Committee
This SAE Aerospace Information Report provides examples of single failure modes for components used in fixed-wing, high-lift actuation systems’ load paths, as well as the typical hazards posed by those failures at the aircraft level.
A-6B3 Electro-Mechanical Actuation Committee
The landing gear, as a crucial component of an aircraft, is pivotal for maintaining the safety and reliability of air travel. This study introduces a data-driven structural optimization method aimed at mitigating the peak strain on the landing gear’s rocker arm. The initial phase involves selecting nine design variables for parametric modeling to generate an initial dataset. Subsequently, the Maximum Information Coefficient (MIC) technique is used to conduct a parameter sensitivity analysis, enabling the identification and elimination of variables with minimal influence. A comparative analysis between the Genetic Algorithm–Backpropagation Neural Network (GA-BPNN) and BPNN reveals that GA-BPNN has a superior fitting capability on the enhanced dataset. By applying Particle Swarm Optimization (PSO), the optimal solution for GA-BPNN is identified. The implementation of this optimized method results in a 38.16% reduction in peak strain, validating its feasibility and reliability in
Chen, HuShi, ShiWang, MengFang, XingboWei, XiaohuiNie, Hong
Flight vehicles operating in low-speed environments face significant aerodynamic challenges due to weak laminar boundary layers, which lead to early flow separation, reduced lift, and increased pressure drag. Airfoils often experience laminar separation bubbles and abrupt stall, making their performance unstable and difficult to predict. This paper aims to address the low-speed aerodynamic parameter analysis using passive flow control techniques on modified NACA 0021 airfoil profile. The novelty of this research method lies in the integration of dimple-based passive flow control structures on the upper surface of a NACA 0021 airfoil specifically designed to delay flow separation and enhance low-speed aerodynamic performance. Unlike most previous studies that focus on conventional vortex generators or active flow control methods, this work uniquely demonstrates that strategically dimple on the airfoil surface modifications significantly improves the lift characteristics. The methodology
Lakshmanan, D.Raman, Senthil Kumar BellaSivakumar, AravinthPillai, Balaji Shanmuga
Carbon fiber-reinforced polymers (CFRPs) have become essential in modern aerospace structures, from fuselage skins and wing components to nacelles, interior structures, and a growing range of primary load-bearing parts. Their high strength-to-weight ratio delivers major benefits in fuel efficiency, payload capacity, and fatigue performance. Yet achieving reliable adhesive bonds on CFRP surfaces remains a persistent engineering challenge. The low intrinsic surface energy of composites - particularly under thermal cycling, vibration, and moisture exposure - limits bond durability unless surfaces are properly prepared. Plasma surface treatment has emerged as a pivotal solution, offering a fast, controllable, and non-destructive way to increase surface energy, improve wettability, and enhance adhesion across complex geometries. This is especially important as the aerospace industry transitions from thermoset to thermoplastic composites (TPCs), which enable faster processing, lower
Between the 1920s and 1930s, aluminum started replacing wood as the primary material in aircraft construction and soon became the backbone of modern aviation. Its popularity stemmed from a combination of properties, high strength-to-weight ratio, corrosion resistance, and ease of forming that made it ideal for demanding aerospace applications. Throughout much of the 20th century, high-strength aluminum alloys dominated aircraft design, accounting for 70-80 percent of commercial airframes and more than half of many military aircraft. Even after the introduction of fiber-polymer composites in the early 2000s, aluminum has remained a critical material because it continues to offer the strength, lightness, and versatility needed for modern aviation. Industry forecasts predict that commercial air travel will double in the next 25 years, which means more pollution will be released into the atmosphere. One way to help reduce these emissions is by building airplane fuselages and wings with
This SAE Aerospace Information Report (AIR) provides an overview of the tire properties, strut properties, damper properties, and other landing gear mechanical properties that contribute to shimmy stability and are required for shimmy analysis. A variety of analysis techniques and assumptions are presented.
A-5 Aerospace Landing Gear Systems Committee
During vehicle launches in 1st gear, a lateral shake (undulation) and a pronounced metallic hitting noise were observed in the underbody. The noise was identified as the propeller shaft's second universal joint (UJ) yoke striking the fuel tank mounting bracket. Sensitivity to these issues varied with acceleration inputs: light pedal input during a normal 1st gear launch on a flat road resulted in minimal undulation, whereas wide open throttle (WOT) conditions in 1st gear produced significant lateral shake and intensified hitting noise. Further investigation revealed that the problem persists across all gears and occurs consistently during normal driving conditions, with continuous impact between the propeller shaft yoke and the fuel tank mounting bracket. Extensive experimental measurements at the vehicle level indicated that these issues were primarily caused by the center-mounted propeller shaft joint deviating from its central position and rotating eccentrically under torque. This
Sanjay, LS, ManickarajaKumar, SarveshKanagaraj, PothirajSenthil Raja, TB, Prem PrabhakarM, Kiran
Nowadays, vehicle enthusiasts often vary the driving patterns, from high-speed driving to off-roading. This leads to a continuous increase in demand for four-wheel drive (4WD) vehicles. A 4WD vehicle have better traction control with enhanced stability. The performance and reliability of 4WD vehicles at high speeds are significantly influenced by driveline stiffness and natural frequency, which are largely affected by the propeller shaft and transfer case. This study focuses on the design optimization of the transfer case and the propeller shafts to enhance the vehicle performance at high speeds. The analysis begins with a comprehensive study of factors affecting the power transfer path, transfer case stiffness, and critical frequency, including material properties, propeller shaft geometry, and different boundary conditions. Advanced computational methods are employed to model the dynamic behavior of the powertrain, identifying the natural frequency of the transfer case and propeller
Kumar, SarveshYadav, SahdevS, ManickarajaSanjay, LKanagaraj, PothirajJain, Saurabh KumarDeole, Subodh M
Axial flux topology motors have the advantages of high torque and power density. Their compact axial length offers design advantages to electric vehicle propulsion systems. However, three major challenges exist. First, motor efficiency needs to be competitive, as concentrated winding usually introduces more harmonics with high stator core loss and permanent magnet eddy current loss, especially at high-frequency condition. Second, thermal management of the stator and rotor is challenging due to the stator being sandwiched between the two rotors. Third, the segmented and trapezoidal-shaped stator core manufacture is difficult because it is formed by hundreds of laminations with varied sizes. To address the challenges, design solutions have been proposed and validated in this study through prototype design and optimization, simulation, and experimental evaluation. With the optimized PM partition and novel hybrid stator core design, the motor peak efficiency reaches 96.5%, while the stator
Yao, JianFedida, VincentDuan, ChengwuZou, YushengKeum, SeungHwanHu, Zhenwen
Rotor balancing is essential for minimizing vibration and noise in industrial and automotive applications. With increasing consumer demand for quieter vehicle interiors, automotive components are now subject to stricter noise and vibration standards. This study investigates the noise generated by fuel supply modules, which play a critical role in delivering pressurized fuel to engines while maintaining low noise levels. An overview of rotor balancing standards is presented, followed by an analysis of how varying degrees of unbalance influence the vibration and noise characteristics of fuel supply modules. To achieve this, rotors were assembled on electric pump samples with defined upper and lower limits of unbalance and conducted tests at the Robert Bosch Ltda laboratory. Utilizing frequency domain analysis, we examined the vibration and noise signals to identify fundamental and harmonic frequencies, thereby assessing the impact of unbalance on overall performance. Measurements were
Aguiar, Rayssa Moreno SilvaAzevedo Fernandes, Luiz EduardoOliveira Melo, Lazaro BeneditoLaura, AnaSouza, LimaBoa, Nathan Barroso Fonte
Tire is the only part of the aircraft that contacts the ground, which not only bears the vertical load and lateral load of the whole aircraft, but also provides adequate ground friction to decelerate the aircraft when braking, so the tires are important parts for aircraft take-off and landing. Besides safety concerns, tire physical properties such as vertical, lateral stiffness as static performance and rolling relaxation length, yawed rolling cornering force as dynamic performance are often required by aircraft manufacturers for analyzing aircraft maneuverability. Besides analysis or similarity by experience from other aircraft projects, tires are often qualified by a number of tests, both static and dynamic, to ensure the safety of tires and acquire tire physical performance data.
Ji, Teng
Aiming at the common health performance influencing factors of the aircraft’s main landing gear retracting hydraulic system, based on its hydraulic structure, the landing gear retracting control AMESim hydraulic system model is established to carry out the study of the typical faults of the aircraft landing gear retracting hydraulic system, such as injection of the hydraulic pump internal leakage, hydraulic oil contamination, and leakage of the actuator cylinder. The curve diagrams of the simulation results are analyzed, and the conclusions of the influence of typical faults on the boundary conditions on the pressure and flow of the hydraulic system are drawn. The results of the simulation are analyzed, and the effect of typical fault boundary conditions on the pressure and flow of the hydraulic system is concluded, which provides a reference for the study of parameter optimization, fault analysis, and health management of the landing gear in engineering applications.
Yu, YahuiCui, Wenhao
To further investigate the effects of the clamping mechanism’s tilt angle and the nose landing gear’s turning angle on the lateral force of the nose landing gear during turning with a towbarless tractor, as well as the changes in the lateral force difference between the inner and outer hinges, a three-dimensional model of the towbarless tractor and the aircraft was first created using SolidWorks software. The dynamic simulation of the model under different conditions was then conducted using Adams software, followed by the analysis of the simulation results. The results indicate that introducing a positive clamping angle leads to an increase in the clamping mechanism’s tilt angle and a decrease in the nose landing gear’s turning angle as the turning radius and speed increase. Consequently, the lateral force difference between the inner and outer hinges of the nose landing gear increases, ranging from 40 kN to 70 kN. To ensure the stability of the clamping device and reduce the lateral
Gao, JianshuHao, ShiyuLiu, Ziao
Aircraft operations during landing or takeoff depend strongly on runway surface conditions. Safe runway operations depend on the tire-to-runway frictional force and the drag offered by the aircraft. In the present research article, a methodology is developed to estimate the braking friction coefficient for varied runway conditions accurately in real-time. To this end, the extended Kalman filtering technique (EKF) is applied to sensor-measured data using the on-ground mathematical model of aircraft and wheel dynamics. The aircraft velocity and wheel angular velocity are formulated as system states, and the friction coefficient is estimated as an augmented state. The relation between the friction coefficient and wheel slip ratio is established using both simulated and actual ground roll data. Also, the technique is evaluated with the simulated data as well as real aircraft taxi data. The accuracy of friction estimation, with and without the measurement of normal reaction force on the
T.K., Khadeeja NusrathSingh, Jatinder
Hydrodynamic energy-saving devices are widely used in ship energy-saving technologies. To enhance the hydrodynamic performance of propellers, a novel annular free-rotating rotor was designed and installed aft of the KP505 propeller. Computational Fluid Dynamics (CFD) simulations were used to evaluate its performance. Additionally, the hydrodynamic performance of single propellers and propellers with added appendages was compared and predicted under different advance coefficients, and the energy-saving effects were assessed. Results show that the propeller with the added appendage achieves a maximum improvement in propulsion efficiency of 6.59% at the design advance coefficient. This confirms that the annular free-rotating rotor has potential for enhancing propeller hydrodynamic performance.
Huang, TangyiLi, DongqinWang, YuLv, Gui
The purpose of this SAE Aerospace Recommended Practice (ARP) is to establish general guidelines for the measurement of static and dynamic characteristic properties of aircraft tires.
A-5C Aircraft Tires Committee
Because regular rear wings on race cars cannot meet all aerodynamic needs, this study tests a new active rear wing on a formula racing car. First, the paper explains the design and key features of the new wing, showing how it helps improve airflow and downforce. Then, the study builds a model of the racing car in Carsim software and adds the new wing to test its performance. After that, simulations compare the new wing to traditional ones, focusing on speed, grip, and handling. The results prove that the new wing makes the car faster and more stable in corners. This means the active rear wing is a better solution than fixed wings, and it could be useful for future race car designs.
Yu, Wanbo
The aircraft environmental envelope, also known as the temperature-altitude envelope, is an important design basis and verification benchmark for aircraft structure and system design, as well as the environmental tolerance of airborne equipments. It is also one of the important operational restrictions required by airworthiness regulations for civil aircraft. This article proposes guiding principles and methods for the design of typical aircraft environmental envelope by constructing a model that matches the atmospheric environment model with the aircraft design constraints, providing reference for the design of environmental envelope for civil aircraft models.
Yang, Yang
This document provides basic information that should be considered when an aircraft tire is needed for a new application. These guidelines are harmonized with existing regulatory and SAE documents and with the Care and Service Manuals of the tire manufacturers. In general, they should be pertinent to both civil and military aircraft.
A-5C Aircraft Tires Committee
The winding configuration of an electric machine has a decisive influence on the properties of a traction drive. When designing the electric drive, the optimum compromise must be found between maximum torque, maximum power and high efficiency over a wide operating range. A decisive factor in this design conflict is the choice of the winding configuration. The concept of winding switching offers a way of solving the design conflict and improving the characteristics of the drive through the additional degree of freedom of the variable winding configuration. Switching the number of parallel winding branches in a serial and parallel configuration is a promising approach to overcome the challenge of a high spread between maximum power and high efficiency in customer related driving scenarios of an electric vehicle. The aim of this study is to identify factors influencing the efficiency improvement potential of the winding switching topology under consideration compared to a reference drive
Oestreicher, RaphaelKoenen, ChristianKulzer, André Casal
In the electrical machines, detrimental effects resulted often due to the overheating, such as insulation material degradation, demagnetization of the magnet and increased Joule losses which result in decreased lifetime, and reduced efficiency of the motor. Hence, by effective cooling methods, it is vital to optimize the reliability and performance of the electric motors and to reduce the maintenance and operating costs. This study brings the analysis capability of CFD for the air-cooling of an Electric-Motor (E-Motor) powering on Deere Equipment's. With the aggressive focus on electrification in agriculture domain and based on industry needs of tackling rising global warming, there is an increasing need of CFD modeling to perform virtual simulations of the E-Motors to determine the viability of the designs and their performance capabilities. The thermal predictions are extremely vital as they have tremendous impact on the design, spacing and sizes of these motors.
Singh, BhuvaneshwarTirumala, BhaskarBadgujar, SwapnilHK, Shashikiran
This study explores the application of Particleworks, a meshless CFD solver based on the Moving Particle Simulation (MPS) method, for simulating hydraulic retarders. Two distinct models were used: one for validating physical fidelity and another for conducting performance-focused design investigations. Validation results demonstrated that Particleworks closely aligns with experimental data from the reference literature, effectively capturing torque variations with rotor speed effect. A sensitivity study also emphasized the importance of particle resolution on accuracy and computational cost. Design studies using an in-house hydraulic retarder model assessed the influence of flow rate, rotor speed, working fluid, temperature, and cup geometry on braking torque. Notably, torque increased with rotor speed and steeper cup angles, while thermal effects and fluid properties significantly impacted performance trends. Comparative analysis with Star-CCM+ showed that Particleworks offers similar
Kumar, Kamal S.Chaudhari, Gunjan B.
This paper presents a comprehensive overview of the methodology employed in leveraging CFD for optimizing HVAC kinematics, focusing on reducing the operating torque by improvising the flap geometry. The aim here is to utilize the CFD simulation in order to predict the torque generated on the actuator motor connected to the flap when the flap is placed in high speed airflow and based on this value work out an optimized geometry of the flap, since its geometry plays a significant role when it comes to determining the torque values. Different flap geometry imparts different torque on motor. This torque is generated because of the force acting on the flap which is acting as a buffer in the path of airflow. The torque generated should be less than the stall torque of the actuator motor in order for smooth performance/movement of the flap. Initial geometry of the flap generated a torque of around 82.5 Ncm which was much higher than the recommendation limit. So in order to bring these torque
Madaan, AshishKumar, RaviBehera, SureshChauhan, Arpit
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