Criteria

Display:

Results

Viewing 211 to 240 of 4781
2012-04-16
Journal Article
2012-01-0576
Shane Richardson, Geoff Hughes, Tandy Wei Pei Pok, Nikola Josevski, Tia Orton, Chris Jones
Within Australia there are seven States and two Territories, each with their own Government Authority which were until recently all using slightly different criteria to define the criteria between a Repairable Write-Off (RWO) and a Statutory Write-Off (SWO). Under the national framework for the management of Written-Off Vehicle's (WOV's) developed by the National Motor Vehicle Theft Reduction Council (NMVTRC) any collision, fire, water or weather-event damaged vehicle declared by an insurer to be a total loss must be classified to be either a SWO or RWO. Under the current Australian regime a SWO may only be sold subject to a statutory restriction that it may only be used for parts or scrap metal. A RWO may be repaired and re-registered subject to the vehicle passing specific safety and identification inspections. A set of State and Territory based technical criteria determine when a WOV should be classified an SWO.
2012-02-29
Technical Paper
2012-01-1507
Antonio Dumas, Michele Trancossi, Mauro Madonia, Maurizio Bonnici, Piergiorgio Scaccaglia, Mario Guareschi
This paper presents a novel concept of acclimatized container to increase people comfort in case of temporary housing. It is based on the ZEBRA concept (Zero Energy Building Renewable Addicted) concept studied by Università of Modena e Reggio Emilia. The original concept developed for industrial building has been extended to mobile metallic housing systems such as the containers transported by trucks which are used for troops and military command during field operations. This system does not require any external source of energy. It requires only the presence of a water well or drilling a hole to place inside a closed loop exchanger which is used to stabilize temperature of internal water which is used as a dynamic thermal barrier which maintains in the wellness conditions inside the mobile housing equipment. Energetic costs of this system are related only to the very reduced energy necessary for water pumping operations.
2012-02-29
Technical Paper
2012-01-1503
Steven Maughan, Nathan Maughan
Temperature and energy losses in Ground Support Equipment (GSE) Pre-Conditioned Air (PCA) flexible ducting have a significant effect on the overall performance the PCA system. Providing the right size (diameter) and sufficiently insulated ducting is essential for the success of the system to adequately cool or heat an aircraft. Traditional HVAC temperature loss and energy loss estimating methods or rules of thumb are difficult to apply due to the specialized nature of the ducting and its application. Using fundamental heat transfer and general energy loss principles, custom tools were developed to model and predict these losses. Empirical testing has been used to verify the predictions. Having these tools enables the correct selection of duct size, length, and type for the particular needs of the PCA system.
2012-02-29
Technical Paper
2012-01-1501
G. Patrick Brown
Examination of existing GSE site and building layouts and specific building elements lead to keys to improved GSE maintenance productivity that can be created with proper building design: Which site layouts provide proper staging and storage areas? Which building configurations help create the most efficient operations? What special building design features and equipment help to expedite vehicle throughput? Conclusions are drawn from design and construction experience, and from the examination of existing facilities, that provide guidelines for planning the new facility. How big should the facility be? How does air traffic growth influence GSE maintenance planning? What factors should be considered in planning a GSE maintenance facility? The paper also offers a brief checklist for the GSE Maintenance Facility planning process.
2011-10-18
Technical Paper
2011-01-2804
Philippe Goupil, Andres Marcos
The state-of-practice for aircraft manufacturers to diagnose guidance & control faults and obtain full flight envelope protection at all times is to provide high levels of dissimilar hardware redundancy. This ensures sufficient available control action and allows performing coherency tests, cross and consistency checks, voting mechanisms and built-in test techniques of varying sophistication. This hardware-redundancy based fault detection and diagnosis (FDD) approach is nowadays the standard industrial practice and fits also into current aircraft certification processes while ensuring the highest level of safety standards. In the context of future “sustainable” aircraft (More Affordable, Smarter, Cleaner and Quieter), the Electrical Flight Control System (EFCS) design objectives, originating from structural loads design constraints, are becoming more and more stringent.
2011-10-18
Technical Paper
2011-01-2703
Mahadevanna Basavaraj Shreshthi, Hanumantha Rao Desu V, Shaik Shafi Ahamed
Diagnosis of the ageing wiring systems in aircrafts, automobiles, industries, transportation, etc is essential. A wide variety of techniques are published in the literature claiming effective diagnosis of wire faults. The focus in this paper is limited to the techniques based on reflectometry principle. These are categorized in to Time Domain Reflectometry [TDR], Frequency Domain Reflectometry [FDR], Spread Spectrum Time Domain Reflectometry [SSTDR], Modified Spread Spectrum Time Domain Reflectometry [M-SSTDR], Noise Domain Reflectometry [NDR], Distributed Reflectometry[DR], Multi Carrier Reflectometry [MCR], Filterbank Multi Carrier Reflectometry [FBMCR] and Time Frequency Domain Reflectometry [TFDR]/Joint Time Frequency Domain Reflectometry [JTFDR] techniques. This paper presents a brief description of these techniques along with their comparison with respect to the key parameters and simulation results of Filter Bank Multi Carrier Reflectometry (FBMCR) technique.
2011-10-18
Technical Paper
2011-01-2608
Hesham Azzam, Jim McFeat
An essential part of the SHM validation effort is to check the presence and adequacy of the methods required to validate the correct functionality of each SHM task, which can be targeted at detecting structural faults. The ultimate proof of the correct functionality is validation evidence, e.g. crack detection evidence, observed during the operation of the aircraft. However, the occurrences of structural faults such as cracks are infrequent, and hence, years of flight tests might be required to collect validation evidence; small numbers of flights would be only sufficient to prove the system's “fitness for flight” and would be insufficient to prove “fitness for purpose”. Validation evidence can be collected during laboratory tests by inducing faults in structural specimens and examining the SHM detection capability.
2011-10-18
Technical Paper
2011-01-2523
Enrique Soriano, Pedro Del Valle
The optimization of the available energy within a vehicle is one of the key drivers for all the ongoing projects. This topic is even more critical when the possibility of recharge energy into the vehicle it is quite improbable or even impossible. Hence all the system involved in the energy management shall create synergies. The Thermal Management is based on two paramount bases. The first one is the location of thermal sources (it can rather been cold sinks or heat sources). The second is the transportation of the energy from one source to a sink. The identification of the sources is based on the vehicle necessities. The definition of the transportation means depend on the vehicle capacities. Traditional system to transport the heat from one place to another are based on fluid displacement. Therefore they need some energy to pump this fluid. In the last years the use of passive transportation means is being developed in the aerospace industry.
2011-10-18
Journal Article
2011-01-2750
Athanasios Lois, Nikolaos Bertos, Athanasios Ziliaskopoylos
The process of checking inspection points on combat aircraft after a mission, is critical for their operational readiness. Manufacturers include specific inspection procedures in their maintenance handbooks. These procedures consist of detailed instructions for each check, the minimum time required to complete each check as well as a suggested sequence. However, it has been observed, that technical crews can complete inspection in less time than suggested by the manual, without violation of the time prescribed for each inspection point. In this work we will try to apply routing algorithms, to improve the total inspection time, by finding the optimal inspection sequence. This will be achieved without violating any constraint set by the manufacturer, except for the small reduction of the service time on some points. The algorithms we will use is the algorithmic set usually applied for the well-known PDPTW (pickup and delivery problem with time windows).
2011-10-18
Journal Article
2011-01-2803
Ali Zolghadri, Anca Gheorghe, Jérôme Cieslak, David Henry, Philippe Goupil, Rémy Dayre, Hervé Le Berre
This paper discusses the design of a model-based fault detection scheme for robust and early detection of runaways in aircraft control surfaces servo-loop. The proposed scheme can be embedded within the structure of in-service monitoring systems as a part of the Flight Control Computer (FCC) software. The final goal is to contribute to improve the performance detection of unanticipated runaway faulty profiles having very different dynamic behaviors, while retaining a perfect robustness. The paper discusses also the tradeoffs between adequacy of the technique and its implementation level, industrial validation process with Engineering support tools, as well as the tuning aspects. The proposed methodology is based on a combined data-driven and system-based approach using a dedicated Kalman filtering. The technique provides an effective method ensuring robustness and good performance (well-defined real-time characteristics and well-defined error rates).
2011-10-18
Journal Article
2011-01-2802
Halim Alwi, Christopher Edwards
This paper presents a preliminary evaluation of the results from using second order sliding mode observer schemes applied to an aircraft fault detection benchmark problem for a class of sensor faults. The scheme has been evaluated on the ADDSAFE Functional Engineering Simulator (FES). This is part of ongoing work on a European FP7 funded project entitled Advanced Fault Diagnosis for Sustainable Flight Guidance and Control (ADDSAFE) which aims to study advanced fault detection and isolation (FDI) methods for aircraft. The simulation and verification FES used in this evaluation incorporates a high fidelity nonlinear aircraft model from AIRBUS (which includes sensor and process noise).
2011-10-18
Technical Paper
2011-01-2704
Ravi Rajamani, Nicholas Waters
The use of Engine Health Management (EHM) systems has been growing steadily in both the civilian and the military aerospace sectors. Barring a few notable exceptions (such as certain temperature and thrust margin monitoring) regulatory authorities around the world have not required these systems to be certified in any way. This is changing rapidly. New airframes and engines are increasingly being designed with the assumption that EHM will be an integral part of the way customers will operate these assets. This leads to a need for better guidelines on how such systems should be certified. The SAE E-32 committee on Propulsion System Health Monitoring is leading an industry-wide effort to develop a set of guidelines for certifying EHM systems.
2011-10-18
Technical Paper
2011-01-2664
Serdar Uckun, Tolga Kurtoglu, Peter Bunus, Irem Tumer, Christopher Hoyle, David Musliner
The complexity of modern aerospace vehicles is growing constantly. New technologies create opportunities for higher levels of integration. Modern vehicles contain a larger number of components that interact with each other in non-linear and often unpredictable ways. Unintended interactions lead to unexpected behaviors and consequences, some of which have proven to be catastrophic. A key technical challenge in developing such complex systems is to ensure that catastrophic subsystem and component interactions are well understood and contained prior to full-scale development. To address these challenges, the U.S. Defense Advanced Research Projects Agency (DARPA) is investing in novel methods for design and verification of complex systems. The META program is specifically aimed at compressing the timeline for product development and deployment of complex defense systems, through model-based design and manufacturing.
2011-10-18
Technical Paper
2011-01-2606
Wolfgang R. Habel, Nadine Kusche, Sven Munzenberger, Vivien G. Schukar
Strain sensors embedded in or attached to structural components have to measure the real deformation of the structure over the whole period of use. The user must know how reliably installed sensors provide strain measurement results. For this purpose, test facilities or coupon tests are used. In order to characterize the strain transfer quality from the host structure into surface-applied strain sensors, a unique testing facility has been developed. This facility can be used both for fiber optic and resistance strain sensors. Originally developed for fiber Bragg grating based sensors, the KALFOS facility (= \bc\ba\blibration of \bfiber \boptic \bsensors) uses Digital Image Correlation (DIC) and Electronic Speckle Pattern Interferometer (ESPI) as unbiased referencing methods. It is possible to determine experimentally the strain transfer mechanism under combined thermal and mechanical loading conditions.
2011-10-18
Journal Article
2011-01-2701
Hannes Wagner, Galin Nikolov, Andreas Bierig, Holger Spangenberg
Flight control systems of civil aircraft have undergone huge developments in the last decades. The current more/ all electric aircraft concepts lead to the replacement of the hydraulic actuators in the primary flight control systems by electromechanical systems. Integrating electromechanical systems in safety critical applications implies three main challenges: (a) the detection of all fault cases which could lead to a safety critical state, (b) finding measurement parameters capable to detect faults, and (c) the development of algorithms to detect faults under all flight conditions. Putting the scope on the health monitoring of the mechanical components of a direct drive actuator, a new technology based on piezoresistive thin film sensors (TFS) is presented and its potential shown by using defective ball bearings as an example.
2011-10-18
Journal Article
2011-01-2714
Vincent Rouet, Bruno Foucher
TRIADE is a European Union project that focuses on the development of technological building blocks for Structure Health Monitoring (SHM) sensing devices in aeronautics. It is funded under the 7th framework program. In terms of objectives, the TRIADE project focuses on providing these technological building blocks and fully integrated prototypes in order to achieve power generation, power conservation, energy management and embedded powerful intelligence for data processing and storage for SHM sensing devices. The principal technological building blocks that the TRIADE project will provide are: - A low profile battery with high energy density which will be able to function in a harsh environment, - An energy harvester from vibration and electromagnetic RF, - Ultra low power sensors which will be designed in SOI technology, and - A neural network for data recording and damage assessment.
2011-10-18
Journal Article
2011-01-2665
Michael Roemer
One of the inherent functions of an integrated vehicle health management (IVHM) system is the reasoning capability that is built on the knowledge of how the individual line replaceable units (LRU) and subsystems are functionally interconnected across the vehicle. Once known and mathematically represented, the IVHM system has the ability to utilize knowledge obtained from the individual LRU/subsystems to determine the overall health state and functional capabilities of the vehicle. This process must go beyond the basic diagnoses of the observed health condition of the isolated subsystems and their remaining functionality. The IVHM reasoning process described herein employs a hierarchical structure that accounts for the failure modes at the LRU level and can also determine the functional impact of those LRUs in terms of remaining functional/operational availability at the subsystem and vehicle levels.
2011-10-18
Journal Article
2011-01-2702
Christian Modest, Kai Schories, Hauke Peer Lüdders, Frank Thielecke
In the paper at hand a model-based development approach for a diagnostic system for a multifunctional fuel cell system architecture will be presented. The approach consists primarily of four parts. The first part is a description of general steps needed to build an accurate component-based model of the system using a state of the art model-based diagnostic reasoning tool. As a first result there will be a static simulation model for nominal system behavior. The second part of the approach deals with the identification of safety critical failure conditions (SCFC) at a system level, e.g. low Power. The SCFCs are then mapped into the model. This means that categorized physical quantities and monitoring executives are chosen, that are appropriate for representing the specific SCFCs, e.g. low voltage at outlet of DC-DC converter module. According to step two there will be conflicts, meaning discrepancies between the simulated nominal and the mapped behavior.
2011-10-18
Journal Article
2011-01-2700
Ahmed Onsy, Brian A. Shaw, Jishan Zhang
Micro-pitting is a fatigue effect that occurs in geared transmission systems due to high contact stress, and monitoring its progression is vital to prevent the eventual failure of the tooth flank. Parameter signature analysis has been successfully used to monitor bending fatigue failure and advanced phases of gear surface fatigue failure such as macro-pitting and scuffing. However, due to modern improvements in steel production the main cause of gear contact fatigue failure can be attributed to surface micro-pitting rather than sub-surface phenomena. Responding to the consequent demand to detect and monitor the progression of micro-pitting, this study experimentally evaluated the development of micro-pitting in spur gears using vibration and oil debris analysis. The paper presents the development of an online health monitoring system for use with back-to-back gear test rigs.
2011-10-18
Journal Article
2011-01-2800
Florian Moliere, Alain Bravaix, Bruno Louis Foucher, Philippe Perdu
Up to now, the reliability achieved by COTS components was largely sufficient for avionics, in terms of failure rate as well as time to failure. With the implementation of new and more integrated technologies (90 nm node, 65 nm and below), the question has arisen of the impact of the new technologies on reliability. It has been stated that the lifetime of these new technologies might decrease. The drift is expected to be technology dependent: integration, technology node, materials, elementary structure choices and process pay a key role. Figures have been published, which gives smaller lifetime than the 30 years generally required for avionics. This would of course impact not only the reliability, but also the maintenance of COTS-based avionics. Hence a new policy should be defined for the whole COTS supply chain. Faced with these impending risks, different methodologies have been developed [1], [2].
2011-10-18
Journal Article
2011-01-2643
Luis Rabelo, Jorge Bardina, Yanshen Zhu, Jeppie Compton
This paper discusses the ground and range operations for a Shuttle derived Heavy-Lift Vehicle being launched from the Kennedy Space Center on the Eastern range. Comparisons will be made between the Shuttle and a heavy lift configuration (SLS-ETF MPCV - April 2011) by contrasting their subsystems. The analysis will also describe a simulation configuration with the potential to be utilized for heavy lift vehicle processing/range simulation modeling and the development of decision-making systems utilized by the range. In addition, a simple simulation model is used to provide the required critical thinking foundations for this preliminary analysis.
2011-10-18
Journal Article
2011-01-2674
Kenneth Pipe, Bernadette Culkin
Current alert setting methodologies based on setting defect detection alert thresholds for vibration and other Health & Usage Monitoring Systems (HUMS) indicators have many limitations, principally there is necessarily a compromise to be achieved between the true negative and false positive diagnostic metrics. This is true for all alert detection techniques from fixed thresholds through to Support Vector Machines. In this paper we describe techniques, validated using helicopter HUMS data, which do not invoke this compromise and independently minimise both the true negative and false positive rates. This paper will also demonstrate how the alert processing can be made more robust and overcome the problems introduced by HUMS data being both non-stationary, non-ergodic i.e. characteristics that change both with time and from platform to platform.
2011-10-04
Technical Paper
2011-36-0279
Carlos Eduardo Viana Ribeiro, Marcelo Lopes de Oliveira e Souza
Life-critical aeronautical projects are increasing their lifecycle up to the point where a product is developed to be available in the market for more than 70 years, but requiring daily service support and replacement parts. Therefore, unavailability of components or services can have a severe impact over the product through its lifecycle. In this work we study some causes of unavailability of components and services and their effects over the lifecycle of an aeronautical project, to propose recommendations, alternatives and actions to be taken in the early phases of project development to help mitigate such effects over the product lifecycle. To do that, we initially present the causes of unavailability of components and services. Then, we discuss some of their effects over the lifecycle of an aeronautical project.
2011-09-13
Technical Paper
2011-01-2247
Mohammad Rezvani, Mohamed AbuAli PhD, Seungchul Lee, Jay Lee, Jun Ni PhD
Batteries are widely used as storage devices and they have recently gained popularity due to their increasing smaller sizes, lighter weights and greater energy densities. These characteristics also render them suitable for powering electric vehicles. However, a key gap exists in that batteries are solely used as storage devices with a lack of information flow. Next-generation battery technologies will constitute the enabling tools that would lead to information-rich batteries, thus allowing the transparent assessment of a battery's health as well as the prediction of a battery's remaining-useful-life (RUL) and its subsequent impact on vehicle mobility. Various methods and techniques have been employed to predict battery RUL in order to improve the accuracy of the State of Charge (SoC) estimation.
2011-09-11
Technical Paper
2011-24-0146
Ivan Arsie, Ivan Criscuolo, Cesare Pianese, Matteo De Cesare
The paper deals with the steady-state optimal tuning of control variables for an automotive turbocharged Diesel engine. The optimization analysis is based on an engine simulation model, composed of a control oriented model of turbocharger integrated with a predictive multi-zone combustion model, which allows accounting for the impact of control variables on engine performance, NOx and soot emissions and turbine outlet temperature. This latter strongly affects conversion efficiency of after treatment devices therefore its estimation is of great interest for both control and simulation of tailpipe emissions. The proposed modeling structure is aimed to support the engine control design for common-rail turbocharged Diesel engines with multiple injections, where the large number of control parameters requires a large experimental tuning effort.
2011-09-11
Technical Paper
2011-24-0145
Fabrizio Ponti, Matteo De Cesare, Vittorio Ravaglioli
Modern internal combustion engine control systems require on-board evaluation of a large number of quantities, in order to perform an efficient combustion control. The importance of optimal combustion control is mainly related to the requests for pollutant emissions reduction, but it is also crucial for noise, vibrations and harshness reduction. Engine system aging can cause significant differences between each cylinder combustion process and, consequently, an increase in vibrations and pollutant emissions. Another aspect worth mentioning is that newly developed low temperature combustion strategies (such as HCCI combustion) deliver the advantage of low engine-out NOx emissions, however, they show a high cylinder-to-cylinder variation. For these reasons, non uniformity in torque produced by the cylinders in an internal combustion engine is a very important parameter to be evaluated on board.
2011-09-11
Technical Paper
2011-24-0067
Christian Donn, Wolfgang Zulehner, Daniel Ghebru, Ulrich Spicher, Matthias Honzen
Advanced thermal management systems in passenger cars present a possibility to increase efficiency of current and future vehicles. However, a vehicle integrated thermal management of the combustion engine is essential to optimize the overall thermal system. This paper shows results of an experimental heat flux analysis of a state-of-the-art automotive diesel engine with common rail injection, map-controlled thermostat and split cooling system. Measurements on a climatic chamber engine test bench were performed to investigate heat fluxes and energy balance in steady-state operation and during engine warm-up from different engine start temperatures. The analysis includes the influence of the operating point and operating parameters like EGR rate, injection strategy and coolant temperature on the engine energy balance.
2011-09-11
Technical Paper
2011-24-0159
Tobias Spilker, Antonius Voncken PhD
Piston rings are faced with a broad range of demands like optimal sealing properties, wear properties and reliability. Even more challenging boundary conditions must be met when latest developments in the fields of direct injection as well as the application of bio fuels. This complex variety of piston ring design requirements leads to the need of a comprehensive simulation model in order to support the development in the early design phase prior to testing. The simulation model must be able to provide classical objectives like friction analysis, wear rate and blow-by. Furthermore, it must include an adequate oil consumption model. The objective of this work is to provide such a simulation model that is embedded in the commercial MBS software ‘FEV Virtual Engine’. The MBS model consists of a cranktrain assembly with a rigid piston that contains flexible piston rings.
2011-09-11
Technical Paper
2011-24-0149
Andrea Catania, Roberto Finesso, Ezio Spessa
A new procedure for the real-time estimation of the EGR rate and charge oxygen concentration has been developed, assessed and applied to a low-compression ratio GMPT-E EURO V diesel engine. High EGR rates are usually employed in modern diesel engines to reduce combustion temperatures and NOx emissions, especially at medium-low load and speed conditions. The EGR rate is usually calibrated in steady-state conditions, but, under transient conditions, it can be responsible for misfire occurrence or non optimal combustion cycles, if not properly controlled. In other words, combustion instabilities can occur, especially during tip-in maneuvers, which imply transition from high EGR (low load) to low EGR (high load) rates. Misfire is determined by a temporary reduction in the intake charge oxygen concentration during the closure of the EGR valve.
2011-09-11
Journal Article
2011-24-0151
Federico Millo, Marco Badami, Andrea Bianco, Enrico Delogu
The fuel injection plays a crucial role in determining the mixture formation process in Gasoline Direct Injection (GDI) engines. Pollutant emissions, and soot emissions in particular, as well as phenomena affecting engine reliability, such as oil dilution and injector coking, are deeply influenced by the injection system features, such as injector geometric characteristics (such as injector type, injector position and targeting within the combustion chamber) and operating characteristics (such as injection pressure, injection phasing, etc.). In this paper, a new CFD methodology is presented, allowing a preliminary assessment of the mixture formation quality in terms of expected soot emissions, oil dilution and injector coking risks for different injection systems (such as for instance multihole or swirl injectors) and different injection strategies, from the early stages of a new engine design.
Viewing 211 to 240 of 4781