bluuebunny/crossref_metadata_2025 huggingface dataset:
The Revenant. Profession, cheval de course
Authors: Porcher Jocelyne , Barreau Sophie , Verdon Aurélie
Published: September 2024

Cet article propose une analyse de l’activité d’un cheval de course nommé « The Revenant » que nous avons suivi en formation à l’école Blondeau en 2017 dans le cadre du programme ChevalEduc. En nous appuyant sur les cadres théoriques de la sociologie des relations de travail entre humains et animaux, de la psychodynamique du travail et de la méthode du parcours de vie, nous retraçons le parcours professionnel de ce cheval, les conditions de son entrée dans le travail, ses relations avec les professionnels, le travail des formateurs avec lui. Notre objectif est de mettre au jour les enjeux des rapports au travail des chevaux de course, c’est-à-dire les causes et les conséquences de la réussite ou de l’échec de la carrière d’un cheval sur sa santé mentale et physique et sur son avenir en lien avec l’organisation générale des courses.
L’ergonomie au cœur d’un processus de création interespèces : penser la scénographie comme interface du travail animal
Authors: Dray Charlène
Published: September 2024

En utilisant les termes « ergonomie du travail » en relation avec le terme « scénographie », cet article développe l’idée que la conception d’outils numériques adaptés à être utilisés par les chevaux sur scène leur permet de participer activement à la représentation théâtrale jusqu’à produire des formes inédites. Nous aborderons quelques dispositifs scénographiques et la manière dont ils induisent des modifications comportementales ou engagent le travail du cheval sur scène dans un sens émancipateur.
Travail collectif et dégagement politique
Authors: Bardot Fabienne
Published: September 2024

Ce texte présente une technique de coopération de médecins du travail d’un même service interentreprises afin d’élaborer des règles de métier sur l’expérience de l’investigation clinique de situations de travail énigmatiques ou compliquées. Il s’agit de discuter sur un cas clinique, présenté oralement ou écrit à l’avance, par un médecin volontaire, de l’analyser sous tous les angles (y compris politiques) et d’en faire une sorte de diagnostic aidant celui qui l’a écrit à passer à l’action. Durant la séance, deux médecins prennent des notes et j’en ferai toujours le compte-rendu final. Le document complet sera ensuite envoyé à chacun des participants comme ressource possible. Ici sont présentées la première séance et deux « petites histoires » de la dernière séance, en 2007.
O trabalhar da dança em uma companhia brasileira à luz da psicodinâmica do trabalho
Authors: Lancman Selma , Petrilli Segnini Marina
Published: September 2024

Este artículo tiene como objetivo informar sobre la investigación realizada en el Balé da Cidade de São Paulo, compañía pública de danza vinculada al Teatro Municipal de São Paulo, Brasil. Se analizó el trabajo de los profesionales de la danza a la luz de la psicodinámica del trabajo. La confrontación de la realidad del trabajo por los bailarines, en la compañía de danza estudiada, expresa la compleja relación entre placer y sufrimiento en el trabajo. Comúnmente, los bailarines se dedican a esta profesión por el placer del movimiento, de realizarse a sí mismos y de un trabajo común. Sin embargo, al enfrentarse a la realidad del trabajo, se encuentran con limitaciones organizativas que pueden conducir a un sentimiento de pérdida de sentido en el trabajo. El malestar psíquico surge en la brecha entre el artista-trabajador (creador) y el trabajador que ejecuta una coreografía.e.
Solving time fractional partial differential equations with variable coefficients using a spatio-temporal meshless method
Authors: Qiu Xiangyun , Yue Xingxing
Published: September 2024

This paper presents a novel spatio-temporal meshless method (STMM) for solving the time fractional partial differential equations (TFPDEs) with variable coefficients based on the space-time metric. The main idea of the STMM is to directly approximate the solutions of fractional PDEs by using a multiquadric function with the space-time distance within a space-time scale framework. Compared with the existing methods, the present meshless STMM entirely avoids the difference approximation of fractional temporal derivatives and can be easily applied to complicated irregular geometries. Furthermore, both regular and irregular nodal distribution can be used without loss of accuracy. For these reasons, this new space-time meshless method could be regarded as a competitive alternative to the conventional numerical algorithms based on difference decomposition for solving the TFPDEs with variable coefficients. Numerical experiments confirm the ability and accuracy of the proposed methodology.
Pythagorean hesitant fuzzy rough multi-attribute decision-making method with application to wearable health technology devices
Authors: Attaullah  , Alyobi Sultan , Alharthi Mohammed , Alrashedi Yasser
Published: September 2024

Identifying the most optimal wearable health technology devices for hospitals is a crucial step in emergency decision-making. The multi-attribute group decision-making method is a widely used and practical approach for selecting wearable health technology devices. However, because of the various factors that must be considered when selecting devices in emergencies, decision-makers often struggle to create a comprehensive assessment method. This study introduced a novel decision-making method that took into account various factors of decision-makers and has the potential to be applied in various other areas of research. First, we introduced a list of aggregation operators based on Pythagorean hesitant fuzzy rough sets, and a detailed description of the desired characteristics of the operators under investigation were provided. The proposed operators were validated by a newly defined score and accuracy function. Second, this paper used the proposed approach to demonstrate the Pythagorean hesitant fuzzy rough technique for order of preference by similarity to ideal solution (TOPSIS) model for multiple attribute decision-making and its stepwise algorithm. We developed a numerical example based on suggested operators for the evaluation framework to tackle the multiple-attribute decision-making problems while evaluating the performance of wearable health technology devices. In the end, the sensitivity analysis has confirmed the performance and reliability of the proposed framework. The findings indicated that the models being examined demonstrated greater reliability and efficacy compared to existing methodologies.
An efficient confidentiality scheme based on quadratic chaotic map and Fibonacci sequence
Authors: Khan Majid , Waseem Hafiz Muhammad
Published: September 2024

In today's rapidly evolving digital landscape, secure data transmission and exchange are crucial for protecting sensitive information across personal, financial, and global infrastructures. Traditional cryptographic algorithms like RSA and AES face increasing challenges due to the rise of quantum computing and enhanced computational power, necessitating innovative approaches for data security. We explored a novel encryption scheme leveraging the quadratic chaotic map (QCM) integrated with the Fibonacci sequence, addressing key sensitivity, periodicity, and computational efficiency. By employing chaotic systems' inherent unpredictability and sensitivity to initial conditions, the proposed method generates highly secure and unpredictable ciphers suitable for text and image encryption. We incorporated a combined sequence from the Fibonacci sequence and QCM, providing enhanced complexity and security. Comprehensive experimental analyses, including noise and occlusion attack simulations, demonstrate the scheme's robustness, resilience, and practicality. The results indicated that the proposed encryption framework offers a secure, efficient, and adaptable solution for digital data protection against modern computational threats.
Reinforcement learning-based adaptive tracking control for flexible-joint robotic manipulators
Authors: Zhong Huihui , Wen Weijian , Fan Jianjun , Yang Weijun
Published: September 2024

In this paper, we investigated the optimal tracking control problem of flexible-joint robotic manipulators in order to achieve trajectory tracking, and at the same time reduced the energy consumption of the feedback controller. Technically, optimization strategies were well-integrated into backstepping recursive design so that a series of optimized controllers for each subsystem could be constructed to improve the closed-loop system performance, and, additionally, a reinforcement learning method strategy based on neural network actor-critic architecture was adopted to approximate unknown terms in control design, making that the Hamilton-Jacobi-Bellman equation solvable in the sense of optimal control. With our scheme, the closed-loop stability, the convergence of output tracking error can be proved rigorously. Besides theoretical analysis, the effectiveness of our scheme was also illustrated by simulation results.
The Rise of Fiscal Capacity: Administration and State Consolidation in the Holy Roman Empire
Authors: Cantoni Davide , Mohr Cathrin , Weigand Matthias
Published: September 2024

This paper studies the role of fiscal capacity in European state consolidation. Our analysis is organized around novel data on the territories and cities of the Holy Roman Empire in the early modern period. Territories implementing an early fiscal reform were more likely to survive, increased in size, and achieved a more compact extent. We provide evidence for the causal interpretation of these results and show key mechanisms: revenues, military investments, and marriage success. The imposition of Imperial taxes, quasi‐random in timing and size, increased the benefits of an efficient tax administration on the side of rulers, driving the implementation of fiscal centralization. Within territories, Chambers became the dominant administrative institution, tilting the consolidating states toward absolutism.
The Impact of Technological Value Recognition on Job Performance Under Digital Transformation
Authors: Zhang Xinhua , Sun Dian , Jiang Renyu , Wang Jingyi , Ma Xiaochun
Published: September 2024

This study focuses on two key factors influencing job performance, technological value recognition (TVR) and emotional labor, that inform the digital labor job performance model. In this study, we argue that digital enterprises enhancing digital workers' TVR and emotional labor can enhance employees' job performance. By analyzing data from 571 digital preschool teachers working in 27 cities in the Yangtze River Delta region of China, we came to the following conclusions: TVR has a positive impact on job performance, emotional labor has a positive impact on job performance, and emotional labor mediates the relationship between TVR and job performance. Our findings also indicate that enhancing the digital resource support employers offered and providing emotional training to employees are two important actions companies can take to improve job performance and innovation capabilities in the digital transformation era.
Circulating Immune Cells from Early- and Late-onset Pre-eclampsia Displays Distinct Profiles with Differential Impact on Endothelial Activation
Authors: Bernier Elsa , Couture Camille , Borchers Anna , Brien Marie-Eve , Graham Charles H , Girard Sylvie
Published: September 2024

Pre-eclampsia (PE) affects 5–8% of pregnancies and has detrimental effects on maternal–fetal health. PE is characterized by de novo hypertension after 20 wk of gestation and end-organ damage. Systemic inflammatory imbalance has been associated with PE, but its contribution to the pathology is poorly understood. Our objective was to investigate maternal systemic immune changes in early-onset PE (EOPE) and late-onset PE (LOPE) versus uncomplicated pregnancies (control [CTRL]), and their contribution to endothelial activation, hallmark of hypertension. Blood samples were analyzed by flow cytometry, multiplex assay, intracellular cytokine staining, and single-cell RNA sequencing. We performed cocultures between circulating immune cells and HUVECs to assess endothelial activation. We found that EOPE had decreased regulatory T cells (4.64±0.33, p < 0.05) and monocytes (33.92±3.08, p < 0.01), whereas LOPE had decreased regulatory T cells (4.60±0.30, p < 0.05) and Th2 cells (7.50±0.62, p < 0.01) versus CTRL. Compared to CTRL, elevated cytokines/chemokines, and growth factors were observed in LOPE, whereas EOPE primarily showed decreased levels. Using intracellular cytokine staining, we observed more monocytes producing IL-12, TNF-α, and IL-1β (all p < 0.05) in LOPE versus CTRL. At the transcriptomic level, we found differentially expressed genes between EOPE and CTRL, predominantly related to upregulation of immune activation pathways. Lastly, EOPE PBMCs induced heightened endothelial activation in vitro observed by increased ICAM-1 and ET-1 (p < 0.05), whereas LOPE PBMCs required LPS stimulation. Although significant proteomic changes are observed in the LOPE group, the EOPE displayed changes mostly at the transcriptomic levels and could induce endothelial activation in vitro.
Design and Prototyping of a New Coaxial VTOL UAV Concept
Authors:   Georgia Institute of Technology, Yao Yuan , Schrage Daniel
Published: September 2024

This paper introduces a new VTOL small UAV concept. This concept features a coaxial rotor design with novel control mechanism. A prototype is constructed to demonstrate the viability and operational principle of the control mechanism. An optimization is conducted on the baseline to reduce hover power and then compared to two existing quadrotors.
Framework for Attitude Controller Development Using Physics Based Flight Dynamics and Hardware-in-the-loop Simulation for Rotary Wing UAVs
Authors:   Indian Institute of Technology Kanpur, Setu Sagar , Abhishek Abhishek , Venkatesan C.
Published: September 2024

This paper presents the development of a framework for establishment of virtual environment for testing and tuning of attitude controller for rotary wing Unmanned Aerial Vehicles (UAVs). A flybarless mini-helicopter UAV is used as the platform for exposition of the proposed framework. A hardware-in-the-loop simulation (HILS) framework is established using a physics based flight dynamics simulation to enable controller design for rotary wing UAVs. The HILS setup includes the flight dynamics model, physical servo actuators and actual UAV autopilot. A computationally light real-time flight dynamics simulation is developed by using the properties estimated using series of simple ground-based experiments to simulate the small unmanned helicopter. The simulation is validated by performing flight tests on the actual UAV. It is demonstrated that accurate physics based simulations can be done without performing system-identification experiments, which can be an issue for an unstable rotary-wing vehicles with unknown dynamics. The utility of the HILS setup has been established by using the tuned PI attitude controller developed in the virtual environment for stabilization of the actual UAV under hovering condition. The validated HILS setup obviated the need for carrying out flight testing for system-identification, as all the relevant parameters required for the real-time simulation could be estimated using ground based tests.
A Cueing Set For Piloted Approach And Hover In Simulated Shipboard Environment
Authors:   NAVAIR - Flight Dynamics, Pritchard James ,   US Navy Test Pilot School, Tritschler John ,   NAVAIR - Flight Dynamics, Allen Joe , Arteche David , Bordner Kaleb , Bumbaugh James
Published: September 2024

Shipboard operations present a unique set of challenges to the pilot-vehicle system. This work addresses problems specific to piloted rotorcraft in the simulated shipboard environment, namely cueing and ship motion, and represents the completion of a three-year effort focused on fixed-base, pilot-in-the-loop rotorcraft flight simulations. Instructors from the United States Naval Test Pilot School, with extensive operational and test experience, participated in the study. Two cueing sets, one for the approach task and another for the hover task, were developed in order to provide intuitive guidance of cyclic and collective inputs. Data were gathered for each task with the cueing system both on and off. The evaluation criteria used to determine the usefulness of the provided cueing were based on pilot workload assessment, profile performance and inceptor activity. The approach task cueing provides the pilot with a preset approach profile defined by altitude and airspeed cueing, while the hover task cueing provides the pilot with a top-down view of helicopter position over the landing spot and a representation of the vehicle’s acceleration vector. Different control response types were assessed, as well as different ship motion intensities. Both tasks show that use of the developed cues allows pilots to achieve greater precision with less overall workload when compared to task performance without cueing available.
Modeling and Simulation in Support of Handling Quality Evaluation of AVX Joint-Multi-Role (JMR) Coaxial Compound Helicopter (CCH)
Authors:   Advanced Rotorcraft Technology Inc., Chang Chongseok ,   AVX Aircraft Company, Lindsey James , Hasbun M. , Saberi H. , He C. , Fortenbaugh Robert
Published: September 2024

This paper describes the modeling and simulation developments made in support of the AVX Joint-Multi-Role (JMR) Coaxial Compound Helicopter (CCH) handling qualities evaluation. The real-time full flight simulation model for the AVX-JMR CCH was developed in FLIGHTLAB and incorporates AVX's fly-by-wire (FBW) control laws. Extensive piloted simulation tests were conducted that cover various mission task elements (MTEs), including those described in the ADS-33E-PRF (Ref. [1]). The MTE test courses were set-up with proper visual cues in accordance with ADS-33E specification. For each MTE test, the test pilots evaluated the performance with ADS-33E handling qualities ratings (HQR) for achievable levels of aggressiveness and control precision. At the same time, the piloted simulation test data were recorded for post-test analysis to demonstrate the evaluation accuracy through comparison with ADS-33E performance standards. In addition to the piloted simulator tests, quantitative analyses were also conducted to assess the AVX-JMR CCH against ADS-33E hover/low speed and forward flight requirements using the ADS-33E handling qualities analysis toolkit in FLIGHTLAB. The quantitative analyses evaluated small and moderate amplitude attitude changes and inter-axis coupling characteristics of the AVX-JMR CCH against the Level 1, 2, and 3 criteria of ADS-33E-PRF. Both the qualitative and quantitative results are presented in this paper to summarize the handling qualities evaluation of the full flight AVX-JMR CCH simulation model.
Characterizing Rotor Performance Changes with Scale in Compressed Air
Authors:   The Pennsylvania State University, Miller Mark , Karli Geoffrey , Rahman Zarif , Kandias Constantinos , Greenwood Eric , Palacios Jose
Published: September 2024

Full-scale rotorcraft aerodynamics are challenging to study in the field due to the lack of control over ambient conditions as well as the complexity and cost of operating a full-scale vehicle. Small-scale testing can provide significant insight into rotorcraft operation and aerodynamics but is limited by the scale factor between model and prototype. An alternative method for testing rotor performance is presented that utilizes compressed air as the working fluid. By compressing the air, flight-scale aerodynamic conditions can be achieved in hover (Reynolds number, Mach number, and advance ratio matched on small models). In this way, new and unconventional rotor configurations can be tested easily and at low cost before implementing larger prototype tests. An experimental facility at Penn State known as the Compressed Air Wind Tunnel (CAWT) is utilized to examine the scaling of thrust and power coefficient for the NASA Dragonfly rotor geometry in the single rotor configuration. Trends in the hover and axial climb results agree with the Dragonfly data obtained in the NASA Transonic Dynamics Tunnel. Scale effects are clearly present for the power coefficient at the lower tested Re, with scale invariance observed at the larger Reynolds numbers which is inline with prior work on single helicopter rotors. The utility of compressed air testing is demonstrated by the relative ease of achieving many operating Re, including full-scale, on a single model geometry.
Extension of the Analytic Vortex Ring State Model for eVTOL Application
Authors:   Seoul National University, Jeong Taemin , Hong Yoonpyo , Yee Kwanjung
Published: September 2024

The engineering model determining the onset of Vortex Ring State (VRS) was applied to eVTOL aircraft, and the effect of different landing trajectories and aircraft drag was investigated. Next, the new model to compare the VRS susceptibility according to the different blade geometries and trajectories is proposed by extending Ahlin & Brown's model to incorporate the two-dimensional thrust and inflow distribution on the rotor disc. For validation, two different trajectories crossing the boundary of the onset of the VRS were simulated, and the results were compared with the Vorticity Transport Method (VTM). Furthermore, the disturbance distribution of moderately and highly twisted blades are compared. The extended model can capture the physical phenomena by the distribution of the disturbances and reflect the effect of blade geometries and trajectories. It is essential to investigate the model further through a correlation analysis using experiments or numerical analysis.
Criticality Determination of HUMS Applications for Life-Adjustment
Authors:   Sikorsky a Lockheed Martin Company, Harrigan Matt
Published: September 2024

Health and Usage Monitoring Systems installed on modern rotorcraft can be used for substantiating component life extensions leveraging actual loads and usage information, reducing uncertainty from assumed loads and usage. One challenge inhibiting fielding such extensions is lack of clearly defined methodology to robustly determine the criticality of the HUMS application. This paper proposes a semi-quantifiable methodology for determining criticality. It is applicable to both loads- and usage-based approaches for part-number-level life adjustments. The approach relies on baseline component design data and is independent of HUMS data to eliminate the possibility of a HUMS errors affecting the bounding criticality assigned to the application. It takes into account the specifics of the component, including the SN working curve, relevant component failure mode severity, and validated compensating provisions that either reduces the likelihood of the component failure mode and/or provides significant "hidden" conservatism not explicitly considered in the assigned uncompensated component failure severity level.
Implementation and Linearization of a State-Space Free Wake Model with a Near-Wake Vortex Lattice Model
Authors:   University of Maryland, Saetti Umberto ,   The Pennsylvania State University, Manjhi Ashish , Bugday Batin , Cocco Alessandro , Horn Joseph
Published: September 2024

This paper describes the implementation and linearization of a state-space free-vortex wake model with a near-wake vortex lattice model as applied to a helicopter rotor. Following a detailed mathematical description, the wake model is implemented for a blade element model of a utility helicopter rotor and tested in multiple flight conditions including hover, forward flight, and vortex ring state (VRS), and for simple control inputs. The model is qualitatively verified against a Vortex Particle Method (VPM). Periodic solutions to the wake model are found by time marching the coupled rotor and vortex wake dynamics for the operating conditions mentioned above. Next, linearized harmonic decomposition models are obtained and validated against nonlinear simulations. Order reduction methods are explored to guide the development of linearized wake models that provide increased runtime performance compared to the nonlinear and linearized harmonic decomposition wake models while guaranteeing satisfactory prediction of the periodic response of the wake.
Maximizing Power Density in the Design of a 100 kW Geared e-Propulsion Unit
Authors:   Hexagon MI, Valente Giorgio ,   Imagination Technologies, Johnston Andrew , Wigmore Matthew , Saysell David , Scott Phillip , Gottardo Davide , Halse Christopher
Published: September 2024

This paper proposes a highly integrated 3-in-1 e-Propulsion unit that exceeds current state-of-the-art power density, utilising low-risk, high TRL technologies. The design process of the e-Propulsion unit is outlined, including the development of a high integrity, fault-tolerant system design targeting DAL-A safety levels. The resulting system concept embodies redundancy throughout the electrical system - two sets of windings in the motor and redundancy built into the power electronics create a robust and efficient architecture. The electrical machine is connected to an optimised single stage planetary gearbox to realise output shaft speed and torque suitable for an eVTOL or eCTOL type application. Both systems are cooled and lubricated by a standalone cooling loop.
Verification of Vortex Ring State Avoidance Diagram Using a Comprehensive Flight Dynamics Helicopter Model
Authors:   Imperial College London, Khamlichi Maha , Vicent Maria
Published: September 2024

This paper addresses the urgent need to enhance rotorcraft safety and performance by developing a prediction methodology for the onset of the Vortex Ring State (VRS), and therefore verifying the VRS avoidance diagram. The objectives of this research are to assess the correlation between predictions generated by a comprehensive flight dynamics code and the latest and most accurate VRS boundary models, validate the VRS avoidance diagram across diverse descending flight conditions, and identify specific parameters indicating the rotor's entry into the VRS. The methodology involves a detailed investigation of 8 descent manoeuvres using a comprehensive flight dynamics code coupled with an advanced free vortex wake model. Results show that the pitch and roll oscillations and thrust fluctuations experienced by helicopters during the VRS are also observed in the model response to steep descent maneuvers. The findings confirm the reliability and applicability of the VRS avoidance diagram, providing valuable insights for improving rotorcraft design and flight control systems. Furthermore, this study presents novel findings regarding the identification of the VRS onset boundary through the observation of pitch and roll rate fluctuations, which contribute to the systematic detection and prevention of the VRS.
Low Noise Helicopter Operations Recommendations to Improve Helicopter Acceptance
Authors:   Airbus Helicopters, Caillet Julien ,   ONERA, Ruaud Elise , Dieumegard Pierre , Guntzer Frédéric
Published: September 2024

This paper presents activities performed in the frame of MOTUS, a DGAC-funded research project, to better understand and reduce annoyance of helicopter operations. It focuses on the operational context of La Réunion island where local authorities intend to define concrete measures to answer multiple complaints from the population. In parallel with ongoing research towards a better understanding of short- and long-term annoyance thanks to both laboratory and field studies, the paper presents an in-depth analysis of helicopter operations in the area. Furthermore, specific recommendations on low noise operations are proposed to local operators in order to reduce their noise footprint and improve helicopter acceptance.
Enhancements, Verification, and VMS Integration of VTOL Concept Vehicle Simulation Models
Authors:   Advanced Rotorcraft Technology Inc., Gladfelter Matthew ,   NASA Ames Research Center, Caudle David , He Chengjian , Saberi Hossein , Singh Raghuvir , Malpica Carlos , Silva Christoper
Published: September 2024

Advanced Rotorcraft Technology (ART) and the NASA Ames Aeromechanics branch have jointly developed FLIGHTLAB® simulation models for Advanced Air Mobility (AAM) VTOL concept vehicles. The overarching purpose of the simulation model development is to establish a set of well defined reference vehicles for FLIGHTLAB users and the rotorcraft community. The ongoing research effort and enhancement of these AAM simulation models to fulfill the role of quality reference vehicles is this paper's focus. The content of this paper expands on the established characteristics of these AAM models in three primary areas. First, enhancement of the lift + cruise and tiltwing models with elastic airframe properties is discussed. The process of setting up the elastic airframe model in FLIGHTLAB, as well as the impacts on flight characteristics are explained. The introduction of the elastic airframe modeling allows these models to be used in flight dynamics, loads, and vibration analysis of the configuration designs. Next, linear model generation from the enhanced simulation model is covered. Confirming the validity of the linearized models is of importance, as these linear models are utilized for flight control design and tuning for these experimental configurations. For the final focus, the progress towards implementation of these models into the NASA Ames Vertical Motion Simulator (VMS) is described. This task seeks to demonstrate the procedures of integrating a FLIGHTLAB flight simulation in the VMS environment, test fully integrated simulation with communication between flight dynamics, control, and propulsion models, and explore the essential aspects of simulation model integration in a full flight simulator environment. This includes I/O definition, initialization, trim, flying, etc. By expanding the capabilities of the AAM simulation models, they continue to develop as valuable and approachable modeling references.
Circular Acoustic Black Holes Integrated into Carbon/Epoxy Stiffened Panels for Noise Control
Authors:   The Pennsylvania State University, Brown Avery ,   Applied Research Lab., Beck Ben ,   Brigham Young University, Shepherd Micah , Smith Edward , Patel Bhavya , Robertson Noah , Bakis Charles , Vlajic Nicholas
Published: September 2024

Carbon fiber reinforced epoxy composite stiffened panels are increasingly being used for structural components in large transport rotorcraft. However, problems are arising with high levels of vibration and interior noise due to the increased stiffness-to-density ratio of composites. The current investigation explores the potential of reducing vibrations in carbon/epoxy stiffened panels with the integration of acoustic black holes (ABH), namely features that incorporate a power law thickness taper. The proposed approach involves designing a taper into the thickness of the blade stiffeners as well as the thin plate. Integration of ABHs into the fuselage structure has the potential to reduce broadband vibrations. Multiple parametric studies with either an ABH integrated into the blade stiffener or a grid of ABHs integrated into the plate were conducted, and the tradeoffs between vibration amplitudes, panel mass, and compressive buckling load were examined. Carbon/epoxy panels were fabricated using vacuum-bag-oven processing with out-of-autoclave prepreg and verified to be of good quality. The integrated velocity response, a proxy for the radiated noise from a panel, and compressive buckling were simulated using finite elements. Comparisons were made to experimentally measured data from modal testing and compression buckling testing. Experimental results indicated that when an ABH is integrated into the blade stiffener and 15 ABHs are integrated into the plate in a grid configuration, the panel mass was unchanged, the integrated velocity response decreased by 2.82 dB, and the buckling load increased by 2.9% compared to a baseline non-tapered design.
Investigation Of Rotor Interactional Aerodynamics Using The Lattice Boltzmann Method
Authors:   Technical University of Munich, Reiser Andreas , Yavrucuk Ilkay
Published: September 2024

This study uses a mid-fidelity, aeromechanics coupled framework using the Lattice-Boltzmann Method (LBM) fluid solver to investigate an experimental coaxial rotor system. Co-rotating and counter-rotating rotor operation scenarios in hover are studied. The rotors are represented as an actuator line in the LBM fluid simulation. Simulation results are compared to experimental data, mid-fidelity and CFD simulation results available in literature. Results indicate that the framework can accurately predict thrust and thrust variations for both upper and lower rotors. Power prediction has deficiencies compared to experimental and CFD results, but is in line with mid-fidelity simulation results in literature. Flow field results are also compared qualitatively with CFD results. Results are sensitive to the actuator line representation of the blade, the inflow sampling, and tip corrections.
Development of Model Based Pilot Controller for Automated Testing of Failure Scenarios in Automatic Flight Control System
Authors:   Turkish Aerospace Industries, Kara Ahmet , Unen Can , Ture Umut
Published: September 2024

This paper examines the Handling Quality Rating (HQR) of the Model-Based Pilot Controller (MBPC) in failure scenarios within the Automatic Flight Control System (AFCS). The MBPC aims to automate the testing of malfunctions in the AFCS of the T625 Gökbey platform. It is constructed using optimal control and estimation theory, with the cost function representing human characteristics determined by weighting matrices. The optimal values of weighting matrices that minimize the cost function are achieved via Genetic Algorithm. This algorithm utilized to systematically minimize user-defined cost functions tailored to optimize performance for selected maneuvers within the scope of ADS33E-PRF, considering user-defined constraints. Time-domain metric performance is provided for two maneuvers: vertical maneuver and hovering turn. The HQRs of the MBPC evaluated according to Power Frequency and Inceptor Peak Power-Phase (IPPP) metrics. The MBPC satisfies the ADS33 desired performance criteria in case of a failure scenario in AFCS throughout the maneuver, achieving satisfactory handling quality results.
A Comparison of Proposed Concepts for Vertiport Markings and Symbology
Authors:   Federal Aviation Administration - FAA, Johnson Charles , Morfitt Grant , Thompson Lacey
Published: September 2024

The unique designs and capabilities of electric Vertical Takeoff and Landing (eVTOL) aircraft present a series of challenges to traditional infrastructure that was designed for conventional rotorcraft. Currently, several civil aviation authorities have released interim, preliminary guidance on aspects of vertical flight infrastructure. This paper presents a comparison of two of the proposed concepts for vertiport markings and symbology, the Federal Aviation Administration (FAA) "Broken Wheel" and the European Union Aviation Safety Association (EASA) "V". These concepts were evaluated over the course of two experimental studies using helicopter-rated pilots in the FAA William J. Hughes Technical Center's S76-D and Loft Dynamics H125 and R22 rotorcraft flight simulators.
Engine Installed Performance Testing Activities
Authors:   Turkish Aerospace, Mayda Anil , Sancar Emre , Daldal A. , Okatan Lütfullah , Çakiroğlu Taylan , Bayat Akay , Ezertaş Ahmet
Published: September 2024

T-625 helicopter, created by the Turkish Aerospace Helicopter Group, serves as a light utility multi role helicopter. It is powered by a pair of CTS800-4AT turboshaft engines, which were developed by the Light Helicopter Turbine Engine Company (LHTEC). This paper presents aspects of performance characteristics for air intakes, exhaust system and engine vents in powerplant integration of the T-625 helicopter, together with the results of engine installed performance flight test campaign, which are performed to determine the engine installation losses.
Rotor Icing and De-icing at DLR's Whirl Tower Test Facility
Authors:   German Aerospace Center - DLR, Bartels Rainer , Kalow Steffen , Schneider Oliver , Sahyoun Dominic , Keimer Ralf , Konrath Robert
Published: September 2024

The paper presents recent and ongoing activities of the German Aerospace Center (DLR) focusing on experimental icing investigations within the nationally funded project InTEnt-H (2018-2022) and progressive activities in continuing internal DLR projects. The aim of InTEnt-H was to investigate innovative de-icing and anti-icing technologies for small and medium-weight helicopters, for which no rotor de-icing technologies exist to date, and to demonstrate the effectiveness of these systems in a suitable test facility. For this purpose, the whirl tower test facility of the DLR in Braunschweig has been converted into an icing test facility that is unique in Europe and will allow for the generation of atmospheric icing conditions. In this facility, de-icing and anti-icing systems for rotor blades can be tested under centrifugal loads and various icing conditions. The paper starts with a short presentation of the retrofitting works at the DLR whirl tower test facility and its major components. Then, the progress of the first test campaigns of the projects are reported. The main focus is on the design and test of the de-icing rotor system, carrying different antiicing/ de-icing technologies. The paper closes with an outlook on the upcoming activities planned to satisfy and verify EASA CS-29 Appendix C icing conditions in the frame of the DLR internal project SAFER2.
Manufacturing of Tools for Support Aviation Production using Fused Filament Fabrication and Fused Deposition Modeling Technologies, on the example of PZL Mielec a Lockheed Martin Company
Authors:   PZL Mielec a Lockheed Martin Company, Banaś Aleksander , Burczy Kamil , Gałaczyński Tomasz , Głodzik Marcin , Wojtuszewski Radosław
Published: September 2024

In the proposed article, the authors will focus on two manufacturing method FUSED FILAMENT FABRICATION (FFF) and FUSED DEPOSITION MODELING (FDM) showing examples of application in aviation production and the resulting benefits.
Airbus Helicopters in America: The Pioneering Years
Authors:   Aeromedia Consultants, Swartz Kenneth
Published: September 2024

The roots of Airbus Helicopters in North America can be traced back to 1955 when the US Army announced it was purchasing three Djinn helicopters for evaluation at Fort Rucker, Alabama.
In the pioneering years, Airbus Helicopters - originally known as Sud Aviation (later Aerospatiale) and Bolkow (later Messerschmitt-Bolkow-Blohm) - worked through at least six different sales agents to break into the United States and Canadian market before they established their own subsidiaries in the 1970s in which merged in 1992 when Eurocopter was formed to combine the helicopter divisions of Aérospatiale and DASA (Deutsche Aerospace Aktiengesellschaft) located in France and Germany.
Today, Airbus Helicopters accounts for a substantial share of new helicopter sales in the United States and Canada, but in the pioneering years it faced an uphill battle against a thriving American helicopter industry and strong "buy America" sentiment, such that the pioneering efforts by the European helicopter to gain a foothold in North America have been largely forgotten.
This paper covers the period from the mid-1950s to 1969 when small number of Sud Aviation Djinn and Alouette II and III helicopters were operated in North America - with the majority migrating to Canada by the late 1960s.
Towards Real-Time Coupled Ship-Rotorcraft Interactional Simulations using GPU-Accelerated Lattice-Boltzmann Method
Authors:   Georgia Institute of Technology, Ashok Shreyas , Rauleder Juergen
Published: September 2024

Many traditional ship-rotorcraft interactional simulation approaches, including those used for pilot training, use a one-way coupling between aerodynamics and flight dynamics. In a one-way coupled method, the standalone ship airwake is superimposed on the rotor, modifying its inflow. However, because the rotor wake does not alter the ship airwake in such a simulation, one-way coupling may not capture all relevant phenomena, such as dynamic ground and wall effects; two-way fully-coupled simulations may be needed. In this study, one- and two-way coupled realtime and near-real-time simulation models of the ship-rotorcraft problem were developed using a GPU-accelerated Lattice-Boltzmann Method (LBM) flow field solver. Comparing flow fields and rotor hub loads, the two-way coupled simulations showed good agreement with new ship-rotor experimental data from Georgia Tech. Real-time full-scale rotorcraft ship approach maneuvers of a notional UH-60A landing on the NATO Generic Destroyer were conducted using a flight controller, and the results showed significant differences in flight control inputs between one- and two-way coupling methods. On the other hand, the presence of ship motion was found to have little effect on the control inputs. The study proved the feasibility of real-time fully-coupled ship-rotorcraft flow field simulations, achieving real-time performance on a single GPU node, and it paves the way for fully-coupled LBM pilot-in-the-loop flight simulation trials.
Dynamic Behavior and Passive Vibration Control of a Flexible Tip-Loaded Support Arm System with Bracing Struts and Tailored Particle Impact Dampers
Authors:   The Pennsylvania State University, Bapat Siddhant , Poreddy Siddharth , Vlajic Nicholas , Auhl Richard , Lesieutre George , Smith Edward
Published: September 2024

Electric Vertical Takeoff Landing (eVTOL) aircraft feature heavy electric motors, battery packs, and rigid fixed-pitch rotors supported on flexible arms. Under substantial time-varying aerodynamic loads associated with variable rotor speeds and, with low intrinsic damping, such lightweight arms respond in bending and torsion at relatively high levels. In this paper, two methods of reducing vibration response in the operating frequency range are explored, one based on damping, the other on stiffness. A tailored particle impact damper system was evaluated experimentally to address near-periodic vibration over a range of frequencies. A forced torsional response test showed consistent 50% vibration reduction, with a 5% mass penalty. To stiffen the system, a cross-braced strut approach linked two arms such that the natural frequencies of their torsion modes would be increased beyond the rotor operating frequency range. A finite element model was developed and validated for a representative eVTOL configuration. Validation was conducted using a scale model aluminum beam set. The addition of a cross-braced strut efficiently stiffened the system, increasing its natural frequency by almost 120%, thus greatly reducing resonant torsional vibration within the operating range. Both approaches to vibration reduction for variable-speed eVTOL aircraft merit continued consideration and research.
F. W. Lanchester: Forgotten Contributions to Rotorcraft Aerodynamic Theory and Vehicle Design
Authors:   Georgia Institute of Technology, Smith Marilyn
Published: September 2024

Frederick William Lanchester (1868-1946) was a British aviation pioneer whose contributions encompass all aspects of aeronautics from basic theory to operations. He was a polymath, talented in many areas beyond engineering, and considered by some as a genius. His contributions are not as recognized as their importance warrants for a multitude of reasons. Many of his efforts were groundbreaking, specifically in the development of rotorcraft, including some concepts and inventions that were well before their time. This paper reintroduces aspects of Lanchester's career that continue to influence the vertical lift community in the twenty-first century.
History and Future of VTOL Air Freight
Authors:   LogistiWerx Inc., Stanzione Kaydon ,   Georgia Institute of Technology, Schrage Daniel
Published: September 2024

Transporting cargo has been a goal of helicopter operations since the earliest days of development. The concept of carrying passengers and cargo from and to remote locations without a runway was originally exploited by the US military in times of peace and war. Early helicopter designs were limited in fixed useful load after onboarding crew and fuel. The 1940's saw helicopters transporting small, lightweight packages on an as-needed basis. The decade of the 1960's started seeing heavy lift helicopters transporting specialty loads in construction and logistics supply, again on an as-needed basis. Today, several Part 135 helicopter operators offer as needed VTOL cargo services. Blade Air Mobility has developed a successful public company business model in Part 135 passenger transport and is also expanding in carrying parcels. With the advent of transformative VTOL air vehicle designs, there has been increasing emphasis on examining parcel delivery on a regular basis. As omni-channel ecommerce drives the ever-increasing need for same day delivery post order. Retails and distributors need to compete with big box retailers and warehouse companies such as Walmart and Amazon, respectively. This results in reducing or eliminating over-the-road transport delivery. The future of parcel and cargo distribution is proposed to be with VTOL air vehicles. To understand the future of such distribution, it is imperative to examine the development of helicopter size, performance, and operational uses.
Rotary-wing vs. Fixed-wing: A Comparative Study of Pilot Performance in eVTOL Simulators
Authors:   Aptima Inc., Osman Maria ,   USAF, Ellis Steve , Ficke Cherrise , Cotton Olivia , Emerson Samantha , Halverson Kent
Published: September 2024

This paper examines the effect of automation on learning for two different types of pilots, rotary-wing and fixed-wing, on flight maneuvers including hovering, vertical takeoff, en route navigation, and approach and landing. Building on existing research, the performance of 11 rotary-wing pilots and 28 fixed-wing pilots was examined during the final repetition of a flight profile to evaluate the level of proficiency gained in approximately 2 hours of training. Our findings suggest that although rotary-wing pilots benefit from their previous hover and take off experience, automation still improved their performance for these maneuvers. Additionally, fixed-wing pilots benefited from higher automation for hovering, en route navigation, and approach and landing maneuvers. These results are discussed in detail in the following sections, along with recommendations for training programs, curricula designers, and manufacturers in the evolving eVTOL landscape.
Agent-based Simulation of UAV based Logistics Networks with Real World Data
Authors:   Technical University Munich, Karpstein Robin , Luis Victor , Holzapfel Florian
Published: September 2024

Applications of Unmanned Aerial Vehicles (UAVs) are on the rise. Particularly within the healthcare sector the potential is huge as its cited as the most accepted application. This paper introduces an agent-based simulation to evaluate the network performance of UAV-based logistics networks in healthcare. The simulation is applied to a hypothetical real-world network. During a simulated day, the UAV fleet performs 212 flights, including 97 delivery flights, amounting to 4264 minutes enroute and covering a distance of 5941 kilometers. The analysis reveals average non-idle and mission utilization of 66% and 33%, respectively. The study also calculates annual network costs of EUR 2.23Mn, with a majority of it being direct costs (54.5%). Further sensitivity analysis identifies the biggest influences of battery capacity, C-Rate, and operator-to-UAV ratio on network performance and costs, highlighting these factors as critical for future optimization. Additionally, the benefit of incorporating various different UAV types into the network is only given if each UAV provides a unique value proposition to enhance the network performance.
The Next Generation of Army Aviation Systems
Authors:   Georgia Institute of Technology, Schrage Daniel
Published: September 2024

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