How Artificial Intelligence Supports Airbus Helicopters to Develop, Qualify and Certify Faster

Nowadays,artificial intelligence is increasingly used to develop and support progress in many fields and industries,such as finance,medical,transportation…,especially for complex problem resolution.The paper presents how Airbus Helicopters introduces artificial intelligence in material&process activities,aiming,amongst other things,to reduce the time to market and optimize qualification then certification costs/risks.The paper integrates the results of a proof of concept,achieved on flame resistance behavior of composite materials,related to interior compartment/cargo self-extinguishing requirements(EASA regulation for Rotorcraft CS27/29§853 and 855)and demonstrates how artificial intelligence supports engineering activities.The significant novelty introduced in this work is the use of advanced data-analysis software to support engineers and experts throughout development and qualification steps.Within this study,various artificial intelligence(AI)models have been trained using available experimental datasets from Airbus Helicopters and suppliers as described in Fig.1.Following that,the trained AI model has permitted to identify the most influencing parameters and allowed to focus interest on both critical and optimal setups to help materials experts to reach targets in terms of material performance.In addition,AI model also allows predicting the fire behavior of the material,for resin/fiber reinforcement/fire agent combinations that have not been tested experimentally.This point could be particularly useful for material development purpose.This work demonstrates that,thanks to artificial intelligence support,Airbus Helicopters has improved its understanding of complex phenomenalike flame resistance behavior.Main influencing parameters have been identified for the different tests configurations.And for each parameter,strong/weak ranges have been established.Doing tests in such critical conditions during materials screening phase should help to avoid failing tests in representative helicopter configurations and permit to speed up helicopter development and certification.The presented study also paves the way for material and processes optimizations for helicopter designs.

Standardization for Additive Manufacturing in Aerospace

Additive manufacturing （AM）--the process of joining materials to make parts from three-dimensional （3D） model data, usually layer upon layer-is an emerging field with a strong need for standardization. Standards serve to develop a common set of basic requirements along the value chain for a harmonized supplier-customer relationship. The benefits of standardization are experienced on both the quality and the commercial sides.

Variations of properties across plate thickness for Al alloy 7010

The variations of electrical conductivity and hardness across the thickness of an Al alloy 7010 plate under the temper condition T7651 were investigated. The electrical conductivity and hardness respond in a reciprocal manner. Cross-sectional slices of the plate subjected to re-solutionising/natural ageing and re-solutionising/artificial ageing show the similar tendencies in property changes as in the as-received raw material. This clearly suggests that the property inhomogeneity across the plate thickness is inherent of the manufacturing route. The differences in properties through the plate thickness are due to the changes in the concentrations of the strengthening alloying elements in the solid solution and the associated changes in microstructure; these are believed to be mainly due to the nature of plate solidification and prolonged high temperature during the rolling operation. The combination of electrical conductivity and hardness can be used as an integral quality property indicator for assessing inhomogeneity of thick products.

Aircraft noise and its nearfield propagation computations

Noise generated by civil transport aircraft during take-off and approach-to-land phases of operation is an environmental problem. The aircraft noise problem is firstly reviewed in this article. The review is followed by a description and assessment of a number of sound propagation methods suitable for applications with a background mean flow field pertinent to aircraft noise. Of the three main areas of the noise problem, i.e. generation, propagation, and ra- diation, propagation provides a vital link between near-field noise generation and far-field radiation. Its accurate assessment ensures the overall validity of a prediction model. Of the various classes of propagation equations, linearised Euler equations are often casted in either time domain or frequency domain. The equations are often solved numerically by computational aeroacoustics techniques, bur are subject to the onset of Kelvin-Helmholtz （K-H） instability modes which may ruin the solutions. Other forms of linearised equations, e.g. acoustic perturbation equations have been proposed, with differing degrees of success.

Micromechanical Analysis of Thermal Expansion Coefficients

Thermal expansion coefficients play an important role in the design and analysis of composite structures. A detailed analysis of thermo-mechanical distortion can be performed on microscopic level of a structure. However, for a design and analysis of large structures, the knowledge of effective material properties is essential. Thus, either a theoretical prediction or a numerical estimation of the effective properties is indispensable. In some simple cases, exact analytical solutions for the effective properties can be derived. Moreover, bounds on the effective values exist. However, in dealing with complex heterogeneous composites, numerical methods are becoming increasingly important and more widely used, because of the limiting applicability of the existing (semi-)analytical approaches. In this study, finite-element methods for the calculation of effective thermal expansion coefficients of composites with arbitrary geometrical inclusion configurations are discussed and applied to a heterogeneous lightning protection coating made from Dexmet&#174 copper foil 3CU7-100FA and HexPly&#174 epoxy resin M21. A short overview of some often used (semi-)analytical formulas for effective thermal expansion coefficients of heterogeneous composites is given in addition.

Landing gear noise control using perforated fairings

Landing gears of commercial aircraft make an important contribution to total aircraft noise in the approach configuration. Using fairings to shield components from high speed impingement reduces noise. Furthermore, perforating these fairings has been confirmed by flight tests to further enable noise reduction. Following an earlier fundamental study of the application of perforated fairings, a study has been performed to investigate and optimize the benefits of bleeding air through landing gear fairings. By means of wind tunnel tests, an aerodynamic and acoustic survey has been performed on a simplified generic main landing gear to explore the influence of （perforated） fairings on the lower part of the gear. The results show that for this specific case, the application of impermeable fairings reduces noise in the mid- and high frequency range by shielding sharp edged components from high velocity impingement. However, below 1 kHz the noise is shown to increase significantly. Application of the perforations is shown to diminish this low frequency increase whilst maintaining the reduction in the mid- and high frequency range. The aerodynamic and acoustic measurements point in the direction of the separated flow of the fairings interacting with the downstream gear components responsible for the low frequency noise increase. Bleeding of the air through the fairings reduces the large scale turbulence in the proximity of these components and hence diminishes the low frequency noise increase.

New Tool Coatings for Light Metal Cutting

New carbon based coatings have been developed for cutting of light metals such as aluminum. These coatings can be used either directly on the tool or as topcoating combined with another hard base coating. Cutting tests show that the coating gives good performance for materials that tend to stick to the cutting tools, such as aluminium alloys, because of the substantial reduction of appearance of the so-called built-up edge (BUE). This results in a longer life time of the tool and smoother surface finish of the cut made in the work-piece material. Especially in dry machining and deep hole drilling this coating performed very well. An overview of the properties and initial cutting results of this coating will be presented. This paper will also present results from recent industrial field tests carried out by a leading European aerospace manufacturer. Cutting forces, BUE formation and surface roughness data will be presented to explain the cutting process during dry machining.

To Learn or Not to Learn:Deep Learning Assisted Wireless Modem Design

Deep learning is driving a radical paradigm shift in wireless communications,all the way from the application layer down to the physical layer.Despite this,there is an ongoing debate as to what additional values artificial intelligence(or machine learning)could bring to us,particularly on the physical layer design;and what penalties there may have?These questions motivate a fundamental rethinking of the wireless modem design in the artificial intelli gence era.Through several physicallayer case studies,we argue for a significant role that machine learning could play,for instance in parallel errorcontrol coding and decoding,channel equalization,interference cancellation,as well as multiuser and multiantenna detection.In addition,we discuss the fundamental bottlenecks of machine learning as well as their potential solutions in this paper.

A Certifiable Framework for Health Monitoring and Management

The scope of this paper is to provide an E2 Eperspective of health monitoring and management(HMM)and structural health mornitoring(SHM)as an integrated system element of an integrated system health monitoring and management(ISHM)system.The paper will address two main topics:(1)The importance of a diagnostics and prognostic requirements specification to develop an innovative health monitoring and management system;(2)The certification of a health monitoring and management system aiming at a maintenance credit as an integral part of the maintenance strategies.The development of a maintenance program which is based on combinations of different types of strategies(preventive,condition-based maintenance(CBM)and corrective maintenance…)for different subsystems or components and structures of complex systems like an aircraft to achieve the most optimized solution in terms of availability,cost and safety/certification is a real challenge.The maintenance strategy must satisfy the technical-risk and cost feasibility of the maintenance program.

Optimal Rendezvous Sequence for LEO Debris Capture

The primary purpose of this study is to exploit the effect of Earth＇s non-sphericity perturbation, particularly due to the J2 term, in order to optimize the capture sequence of potential orbital debris, that is the cumulative AV associated to the transfers between one object and the others. As results of several researches and model predictions, many international agencies agree that the growing population of objects and debris in LEO （low earth orbits）, will follow a diverging trend in the future. This, in turn, would constitute a serious threat to circum-terrestrial space safety and sustainability. In LEO, the ,J disturbance is prevailing over the others, and it acts by affecting the longitude of the ascending node （Ω）, the argument of perigee （ω） and, accordingly, the true anomaly （v）. Therefore, the goal of optimizing the AV is achieved by taking advantage of the rate of variation of Ω and ω, thereby compensating for the △Ω and △ω, present between the orbital transfer vehicle （chaser） and the debris to be captured （target）. Obviously, the perturbation will lead to favourable variations of the orbital parameters only for some combinations of Ω and ω. Yet the presence of a debris population with random distribution of Ω and ω, makes this application particularly suited to the problem. The single maneuver has been modelled with a 4-impulse time fixed rendezvous and the optimization problem has been addressed by implementing a hybrid evolutionary algorithm, which adopts, in parallel, three different strategies, namely, genetic algorithm, differential evolution and particle swarm optimization.

Metabolic and physiological regulation of Chlorella sp.(Trebouxiophyceae, Chlorophyta) under nitrogen deprivation

A freshwater green microalgae Chlorella sp., UMACC344 was shown to produce high lipid content and has the potential to be used as feedstock for biofuel production. In this study, photosynthetic effciency, biochemical pro?les and non-targeted metabolic pro?ling were studied to compare between the nitrogen-replete and deplete conditions. Slowed growth, change in photosynthetic pigments and lowered photosynthetic effciency were observed in response to nitrogen deprivation. Biochemical pro?les of the cultures showed an increased level of carbohydrate, lipids and total fatty acids, while the total soluble protein content was lowered. A trend of fatty acid saturation was observed in the nitrogen-deplete culture with an increase in the level of saturated fatty acids especially C16:0 and C18:0, accompanied by a decrease in proportions of monounsaturated and polyunsaturated fatty acids. Fifty-nine metabolites, including amino acids, lipids, phytochemical compounds, vitamins and cofactors were signi?cantly dysregulated and annotated in this study. Pathway mapping analysis revealed a rewiring of metabolic pathways in the cells, particularly purine, carotenoid, nicotinate and nicotinamide, and amino acid metabolisms. Within the treatment period of nitrogen deprivation, the key processes involved were reshu ? ing of nitrogen from proteins and photosynthetic machinery, together with carbon repartitioning in carbohydrates and lipids.

Communication Mediated through Natural Language Generation in Big Data Environments: The Case of Nomao

Along with the development of big data, various Natural Language Generation systems (NLGs) have recently been developed by different companies. The aim of this paper is to propose a better understanding of how these systems are designed and used. We propose to study in details one of them which is the NLGs developed by the company Nomao. First, we show the development of this NLGs underlies strong economic stakes since the business model of Nomao partly depends on it. Then, thanks to an eye movement analysis conducted with 28 participants, we show that the texts generated by Nomao’s NLGs contain syntactic and semantic structures that are easy to read but lack socio-semantic coherence which would improve their understanding. From a scientific perspective, our research results highlight the importance of socio-semantic coherence in text-based communication produced by NLGs.

Analytical Method to Monitor Industrial Pickling Baths Initially Constituted by HF, HNO₃

The present study couples the acid/basis titration and the ICP analysis in order to monitor the concentrations of nitric and hydrofluoric acids, and presents into baths used to pickle alloys of titanium or stainless steel, largely employed in the aeronautic industry. The pickling of the alloys releases various metallic cations able to react with HF in order to lead to metal-fluoride complexes and free H+, the last being able to react with the basis. In this study, it was determined: the most significant correlations providing the number of the protons released by the complexation of the metallic cation by the fluoride. The proposed method based on: 1) these correlations;2) the titration pH = f(VKOH) curves;and 3) the content of metallic cations determined by ICP, enables the monitoring of the content of HNO3 and HF into the pickling bath. Assuming that one bath was used for one type of alloy (alloys of Titanium for example, or alloys of stainless steel), then the proposed method appears providing reliable concentration values of both acids as well as metallic cations.

Power Supply for a Wireless Sensor Network： Airliner Flight Test Case Study

In this paper, we present hands-on experience related to on-going implementation in aircraft of power supply for a wireless sensor network deployed for aerodynamic flight tests. This autonomous battery-free power supply is capturing, managing and storing primary energy from the environment, using solar light and PV （photovoltaic） cells. For practical purposes, it is also equipped with an auxiliary power input. The specifications are detailed, the general architecture is presented and justified, and test results are discussed.

Design and Experimental Testing of a Moving Coil Actuator with Compensation Coil

Hydrogen-powered electric aircraft have attracted significant interests aiming to achieve decarbonization targets.Onboard DC electric networks are facing great challenges in DC fault protection requirements.Vacuum interrupters are widely used in low voltage and medium voltage power systems due to being environmentally friendly with low maintenance.In this paper a moving coil actuator with compensation coils for a vacuum interrupter,as part of a hybrid direct current circuit breaker,is designed and experimentally tested.Compensation coils are used to improve operating speed compared with original moving coil actuator.Comparisons between four possible connections of compensation coils and original moving coil actuator are carried out.Experimental results show comparisons between different connections of actuator coils in terms of opening time and coil current with a range of pre-charged capacitor voltages.Dynamic performance of each actuator connection is also compared.The actuator with compensation coils is shown to have a higher current rising rate and achieve faster opening speed,which is a critical requirement for electric aircraft network protection.The parallel connection actuator achieves the highest opening speed within 3.5 ms with capacitor voltage of 50 V.

TOWARDS AVOIDING THE HIDDEN TRAPS IN QFD DURING REQUIREMENTS ESTABLISHMENT

The Quality Function Deployment （QFD） is a useful and representative methodology to transform customer needs into different level of requirements in a system hierarchy. Simplifications that are based on assumptions are ubiquitous in the QFD, but these underlying assumptions possibly do not hold true, which renders the simplifications unjustified. Additionally, these assumptions are usually not verified within the context of the application domain. This paper identifies and illustrates eight hidden traps in QFD during the process of establishing the requirements, where the assumptions, and therefore, the simplifications made are not reasonable. These traps are implicit in the understanding of customer needs, establishment of system requirements and the flow down of these requirements to lower levels of the system hierarchy. Suggestions are given to help avoiding these hidden traps, thereby eliminating or alleviating their potentially detrimental effects. The intent of the paper is to make readers aware of these traps when applying QFD for the establishment of requirements, so that they may utilize QFD with a better understanding of its limitations and develop higher quality specifications.

Environmental analysis of innovative sustainable composites with potential use in aviation sector -A life cycle assessment review

The forecast of growing air transport in the upcoming decades faces the challenge of an increasing environmental impact.Aviation industry is working on promising technologies to mitigate this environmental impact.Lightweight design is a strong lever to lower the fuel consumption and,consequently,with it the emissions of aviation.High performance composites are a key technology to help achieve these aims thanks to their favourable combination of mechanical properties and low weight in primary structures.However,mainly synthetic materials such as petrol based carbon fibres and epoxy resins are used nowadays to produce composite in aviation.Renewable materials like bio-based fibres and resin systems offer potential environmental advantages.However,they have not found their way into aviation,yet.The reasons are reduced mechanical properties and,especially for the use of natural fibres,their flammability.Improvements of these shortcomings are under investigation.Therefore the application of bio-based and recycled materials in certain areas of the aircraft could be possible in the future.Good examples for applications are furnishings and secondary structures.The motivation for this paper is to give an overview of potential environmental properties by using such eco-materials in aviation.Life cycle assessment(LCA) is a tool to calculate environmental impacts during all life stages of a product.The main focus is laid on the bio-fibres flax and ramie,recycled carbon fibres and bio-based thermoset resin systems.Furthermore an overview of environmental aspects of existing composite materials used in aviation is given.Generally,a lack of LCA results for the substitution of synthetic materials by bio-based/recycled composite materials in aviation applications has been identified.Therefore,available information from other transport areas,such as automotive,has been summarized.More detailed LCA data for eco-composite materials and technologies to improve their properties is important to understand potential environmental effects in aviation.

Simulations of helicopter ditching using smoothed particle hydrodynamics

The present work has been performed in the context of the European H2020 project increased SAfety and Robust certification for ditching of Aircrafts and Helicopters(SARAH)dedicated to improving the safety during aircraft ditching,together with a better understanding of the physics involved during those crucial events.Both numerical and experimental aspects are explored during this project.The present study focuses on the application of the smoothed particle hydrodynamics(SPH)method to the simulation of helicopter ditching,as this method has proved to be particularly adapted to free surface impact cases.Simulations are performed for three different impact configurations,for which the numerical solutions are compared with the experimental results(forces and kinematics)obtained at the wave basin of Ecole Centrale Nantes on a mock-up shape provided by Airbus Helicopters.Elements of sensitivity analysis are also provided when needed,to assess the role of some parameters involved in the helicopter behavior and the fluid pressure forces exerted during the impact.

Future aircraft cabins and design thinking:optimisation vs.win-win scenarios

With projections indicating an increase in mobility over the next few decades andannual flight departures expected to rise to over 16 billion by 2050,there is a demand for theaviation industry and associated stakeholders to consider new forms of aircraft and technology.Customer requirements are recognized as a key driver in business.The airline is the principalcustomer for the aircraft manufacture.The passenger is,in turn,the airline's principal customerbut they are just one of several stakeholders that include aviation authorities,airport operators,air-traffic control and security agencies.The passenger experience is a key differentiator usedby airlines to attract and retain custom and the fuselage that defines the cabin envelope for thein-flight passenger experience and cabin design therefore receives significant attention for newaircraft,service updates and refurbishments.Decision making in design is crucial to arrivingat viable and worthwhile cabin formats.Too litle innovation will result in an aircraftmanufacturer and airlines using its products falling behind its competitors.Too much mayresult in an over-extension with,for example,use of immature technologies that do not havethe necessary reliability for a safety critical industry or sufficient value to justify the develop-ment effort.The multiple requirements associated with cabin design,can be viewed as an area for optimisation,accepting trade-offs between the various parameters.Good design,however,is often defined as developing a concept that resolves the contradictions and takes the solutiontowards a win-win scenario.Indeed our understanding and practice of design allows forbehaviors that enhance design thinking through divergence and convergence,the use ofabductive reasoning,experimentation and systems thinking.This paper explores and definesthe challenges of designing the aireraft cabin of the future that will deliver on the multiplerequirements using experiences from the A350 XWB and future cabin design concepts.Inparticular the paper explores the value of implementing design thinking insights in engineeringpractice and discusses the relative merits of decisions based on optimisation versus win-winscenarios for aircraft cabin design and wider applications in aerospace environments.Theincreasing densification of technological opportunities and shifting consumer demand coupledwith highly complex systems may ultimately challenge our ability to make decisions based onoptimisation balances.From an engineering design perspective optimisation tends to precludecertain strategies that deliver high quality results in consumer scenarios whereas win-winsolutions may face challenges in complex technical environments.