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2016-10-25
Technical Paper
2016-36-0503
Marcelo Lopes de Oliveira e Souza, Roberta de Cássia Ferreira Porto
Systems such as satellites, airplanes, cars and air traffic controls are becoming more and more complex and/or highly integrated. These systems integrate several technologies inside themselves, and must be able to work in very demanding environments, sometimes with few, or none, maintenance services, because of their severe conditions of work. To survive to such severe work conditions, the systems must present high levels of reliability, which are achieved through different approaches and processes. Therefore, it is necessary that the processes of decision analysis and making are progressively improved, taking into account experiences collected before by several technological communities, and then propose efficient modifications in the local processes. These experiences influence the proposition and improvement of several Reliability Standards Series taken by four different approaches and several technological communities.
2016-09-20
Technical Paper
2016-01-1997
Wei Wu, Yeong-Ren Lin, Louis Chow, Edmund Gyasi, John P. Kizito, Quinn Leland
Abstract The aircraft electromechanical actuator (EMA) cooling fan is a critical component because an EMA failure caused by overheating could lead to a catastrophic failure in aircraft. Fault tree analysis (FTA) is used to access the failure probability of EMA fans with the goal of improving their mean time to failure (MTTF) from ∼O(5×104) to ∼ O(2.5×109) hours without incurring heavy weight penalty and high cost. The dual-winding and dual-bearing approaches are analyzed and a contra rotating dual-fan design is proposed. Fan motors are assumed to be brushless direct current (BLDC) motors. To have a full understanding of fan reliability, all possible failure mechanisms and failure modes are taken into account.
2016-04-11
Journal Article
2016-01-9081
Sean A. McKelvey, Yung-Li Lee
Abstract Multiaxial loading on mechanical products is very common in the automotive industry, and how to design and analyze these products for durability becomes an important, urgent task for the engineering community. Due to the complex nature of the fatigue damage mechanism for a product under multiaxial state of stresses/strains which are dependent upon the modes of loading, materials, and life, modeling this behavior has always been a challenging task for fatigue scientists and engineers around the world. As a result, many multiaxial fatigue theories have been developed. Among all the theories, an existing equivalent stress theory is considered for use for the automotive components that are typically designed to prevent Case B cracks in the high cycle fatigue regime.
2015-09-15
Technical Paper
2015-01-2500
Brigitte Vasques
The drilling of multi layers composite stacks remains a common process in aerospace industry. Research of productive solutions such as one shot and dry drilling operations to avoid reaming and lubrication are contemplated by aerospace customers on titanium multi layers composite applications. Those solutions permit to reduce the number of finishing operation and drilling time. Special ADEs (Advanced Drilling Equipment) machines are used to drill aircraft components in limited access areas. Parameters such as cutters, ADE machines type, rigidity clamping, cutting conditions, speed, feed, chip fragmentation and extraction are related and influence the holes quality. Titanium (TA6V) thickness and cutting configuration influence the cutter wear development. In this work, ADE and specific cutter geometries developed by Apex are used for the one shot dry drilling of titanium. Carbide cutters have been chosen for their resistance to the heat developed by titanium drill.
2015-09-15
Technical Paper
2015-01-2615
Donald Jasurda
The aerospace industry is continually becoming more competitive. With an aircraft's large number of components, and the large supplier base used to fabricate these components, it can be a daunting task to manage the quality status of all parts in an accurate, timely and actionable manner. This paper focuses on a proof of concept for an aircraft fuselage assembly to monitor the process capability of machined parts at an aircraft original equipment manufacturer (OEM) and their supply chain. Through the use of standardized measurement plans and statistical analysis of the measured output, the paper will illustrate how stakeholders can understand the process performance details at a workcell level, as well as overall line and plant performance in real time. This ideal process begins in the product engineering phase using simulation to analyze the tolerance specifications and assembly process strategy, with one of the outputs being a production measurement plan.
2015-09-15
Technical Paper
2015-01-2555
Ephraim Suhir, Alain Bensoussan, Johann Nicolics
There is a concern that the continuing trend on miniaturization (Moore's law) in IC design and fabrication might have a negative impact on the device reliability. To understand and to possibly quantify the physics underlying this concern and phenomenon, it is natural to proceed from the experimental bathtub curve (BTC) - reliability “passport” of the device. This curve reflects the combined effect of two major irreversible governing processes: statistics-related mass-production process that results in a decreasing failure rate with time, and reliability-physics-related degradation (aging) process that leads to an increasing failure rate. It is the latter process that is of major concern of a device designer and manufacturer. The statistical process can be evaluated theoretically, using a rather simple predictive model.
2015-09-15
Journal Article
2015-01-2388
Luis Rabelo, Tom Clark
Abstract Although a multitude of anomaly detection and fault isolation programs can be found in the research, there does not appear to be any work published on architectural templates that could take advantage of multiple programs and integrate them into the desired systems. More specifically, there is an absence of a methodological process for generating anomaly detection and fault isolation designs to either embed within new system concepts, or supplement existing schemes. This paper introduces a new approach based on systems engineering and the System Modeling Language (SysML). Preliminary concepts of the proposed approach are explained. In addition, a case study is also mentioned.
2015-09-15
Technical Paper
2015-01-2556
Thomas Rousselin, Guillaume Hubert, Didier Regis, Marc Gatti
Abstract The changes brought by the increasing integration density and the new technological trends have pushed the reliability at its limit. Safety analysis for critical system such as embedded electronics for avionics systems needs to take into account these changes. In this paper, we present the consequences on the deep sub-micron (DSM) CMOS devices concerning their single event effect (SEE) sensitivity. We also propose a new modeling method in order to address these issues.
2015-09-15
Technical Paper
2015-01-2549
Marc-André Léonard, Jean-François Boland, Christophe Jégo, Claude Thibeault
Abstract Design assurance guidance such as DO-254, and commercial off the shelf (COTS) increasing popularity in high critical mission have pushed the validation and verification methodologies to improve by integrating fault tolerance analysis in reliability assessment. A novel methodology for analysing the sensitivity of digital designs to single event upsets (SEU) is proposed. We first characterize basic combinational circuit models using fault injection via mutation technique at low level of abstraction. Error analysis is performed at primary outputs to identify patterns that are collected in a faulty behaviour library. This library is then used at a high level of abstraction to execute a sensitivity analysis on a digital design model. A reliability report is then generated showing the soft error rate (SER) and the benign errors count. We proved our methodology by analysing the radiation sensitivity of a discrete wavelet transform architecture using two different sets of data.
2014-09-16
Technical Paper
2014-01-2262
Rostislav Sirotkin, Galina Susova, Gennadii Shcherbakov
Abstract Within the Russian aviation industry the necessary level of reliability risks related to the failures of aircraft mechanical parts and systems vital to the safety of flight is assured via the system of activities aimed at influencing the parameters of critical parts (CP). The goal of the system is to provide a relationship between activities aimed at prevention of dangerous failures at all phases of airplane life cycle. The system operation is regulated by the normative documents and by controlling their observance. Normative documents containing requirements and recommendations were developed about 15 years ago based on the industry experience and traditions and taking into account the requirements of AS9100 series of international standards [2] wherever possible. The documents were developed taking into account typical safety management errors outlined in [1].
2014-09-16
Technical Paper
2014-01-2160
Wei Wu, Yeong-Ren Lin, Louis Chow
Abstract In this paper, we address the thermal management issues which limit the lifespan, specific power and overall efficiency of an air-cooled rotary Wankel engine used in Unmanned Air Vehicles (UAVs). Our goal is to eliminate the hot spots and reduce the temperature gradients in the engine housing and side plates by aggressive heat spreading using heat pipes. We demonstrate by simulation that, for a specific power requirement, with heat spreading and more effective heat dissipation, thermal stress and distortion can be significantly reduced, even with air cooling. The maximum temperature drop was substantial, from 231°C to 129°C. The temperature difference (measure of temperature uniformity) decreased by 8.8 times (from 159°C to 18°C) for a typical UAV engine. Our heat spreaders would not change the frontal area of the engine and should have a negligible impact on the installed weight of the propulsion assembly.
2014-09-16
Journal Article
2014-01-2110
David Gras, Christophe Pautrel, Amir Fanaei, Gregory Thepaut, Maxime Chabert, Fabien Laplace, Gonzalo Picun
Abstract In this paper we present a set of integrated circuits specifically designed for high temperature power applications such as isolated power transistor drivers and high efficiency power supplies. The XTR26010 is the key circuit for the isolated power gate drive application. The XTR26010 circuit has been designed with a high focus in offering a robust, reliable and efficient solution for driving a large variety of high-temperature, high-voltage, and high-efficiency power transistors (SiC, GaN, Si) existing in the market. The XTR40010 is used for isolated data communication between a microcontroller or a PWM controller and the power driver (XTR26010). The isolated power transistor driver features a dual turn-on channel, a turn-off channel and a Miller Clamp channel with more than 3A peak current drive strength for each channel. The dV/dt immunity between XTR26010 and XTR40010 exceeds 50kV/μs.
2014-09-16
Journal Article
2014-01-2144
Marco Amrhein, Jason Wells, Eric Walters, Seana McNeal, Brett Jordan, Peter Lamm
Abstract Transient operating conditions in electrical systems not only have significant impact on the operating behavior of individual components but indirectly affect system and component reliability and life. Specifically, transient loads can cause additional loss in the electrical conduction path consisting of windings, power electronic devices, distribution wires, etc., particularly when loads introduce high peak vs. average power ratios. The additional loss increases the operating temperatures and thermal cycling in the components, which is known to reduce their life and reliability. Further, mechanical stress caused by dynamic loading, which includes load torque cycling and high peak torque loading, increases material fatigue and thus reduces expected service life, particularly on rotating components (shaft, bearings).
2014-09-16
Journal Article
2014-01-2128
Ephraim Suhir, Alain Bensoussan
Abstract The attributes of and challenges in the recently suggested probabilistic design for reliability (PDfR) concept, and the role of its major constituents - failure oriented accelerated testing (FOAT) and physically meaningful predictive modeling (PM) - are addressed, advanced and discussed. The emphasis is on the application of the powerful and flexible Boltzmann-Arrhenius-Zhurkov (BAZ) model, and particularly on its multi-parametric aspect. The model can be effectively used to analyze and design optoelectronic (OE) devices and systems with the predicted, quantified, assured, and, if appropriate and cost-effective, even maintained probability of failure in the field. The numerical example is carried out for an OE system subjected to the combined action of the ionizing radiation and elevated voltage as the major stimuli (stressors). The measured leakage current is used as a suitable characteristic of the degree of degradation.
2014-09-16
Technical Paper
2014-01-2197
Didier Regis, Julie Berthon, Marc Gatti
Abstract For more than 40 years, Gordon Moore's experimental law has been predicting the evolution of the number of transistors in integrated circuits, thereby guiding electronics developments. Until last years, this evolution did not have any measurable impact on components' quality; but the trend is beginning to reverse. This paper is addressing the impact of scaling on the reliability of integrated circuits. It is analyzing - from both qualitative and quantitative point of view - the behavior of Deep Sub-Micron technologies in terms of robustness and reliability. It is particularly focusing on three basics of safety analyses for aeronautical systems: failure rates, lifetimes and atmospheric radiations' susceptibility.
2014-09-16
Technical Paper
2014-01-2208
Michael Baldwin
Abstract This paper will illustrate how the increasing electrical power demands of military and aerospace applications can continue to successfully be met by high performance electromechanical relays. To meet these higher demands engineering compatibility must be properly understood between the intended application demands and relay switching performance parameters. With high performance electromechanical relays continuing to play a critical part in military and aerospace applications it is more important than ever that engineers capture all of the electrical power switching requirements. A critical area within powering military and aerospace systems is relay life when capacitive load switching. Capacitive loads generate high current levels that are transient in duration and often adversely affect the relay lifespan at the component level and the military or aerospace application reliability at the systems level.
2014-04-01
Technical Paper
2014-01-0715
Jin Woo Lee, Efstratios Nikolaidis
Abstract Inflatable space structures can have lower launching cost and larger habitat volume than their conventional rigid counterparts. These structures are made of composite laminates, and they are flexible when folded and partially inflated. They contain light-activated resins, and can be cured with the sun light after being inflated in space. A spacecraft can burst due to cracks caused by meteor showers or debris. Therefore, it is critical to identify the important fracture failure modes, and assess their probability. This information will help a designer minimize the risk of failure and keep the mass and cost low. This paper presents a probabilistic approach for finding the required thickness of an inflatable habitat shell for a prescribed reliability level, and demonstrates the superiority of probabilistic design to its deterministic counterpart.
2013-09-17
Technical Paper
2013-01-2173
Ali Aidibe, S. Antoine Tahan, Jean-Francois Lalonde
Nowadays, optimization of manufacturing and assembly operations requires taking into account the inherent processes variations. Geometric and dimensional metrology of mechanical parts is very crucial for the aerospace industry and contributes greatly to its. In a free-state condition, non-rigid parts (or compliant parts) may have a significant different shape than their nominal geometry (CAD model) due to gravity loads and residual stress. Typically, the quality control of such parts requires a special approach where expensive and specialized fixtures are needed to constrain dedicated and follow the component during the inspection. Inspecting these parts without jig will have significant economic impacts for aerospace industries, reducing delays and the cost of product quality inspection. The Iterative Displacement Inspection (IDI) algorithm has been developed to deal with this problem.
2013-09-17
Journal Article
2013-01-2201
Joshua Benhabib
Manufacturing operations introduce unreliability into hardware that is not ordinarily accounted for by reliability design engineering efforts. Inspections and test procedures normally interwoven into fabrication processes are imperfect, and allow defects to escape which later result in field failures. Therefore, if the reliability that is designed and developed into an equipment/system is to be achieved, efforts must be applied during production to insure that reliability is built into the hardware. There are various ways to improve the reliability of a product. These include: Simplification Stress reduction/strength enhancement Design Improvement Using higher quality components Environmental Stress Screening before shipment Process Improvements, etc. This paper concentrates on ‘Manufacturing Process Improvement’ effort through the use of design of experiments, (DOE). Hence, improved levels of reliability can be achieved.
2013-09-17
Journal Article
2013-01-2198
Maryam Aramesh, Xavier Rimpault, Zdzislaw H. Klim, Marek Balazinski
Metal matrix composites (MMCs) exhibit superior characteristics such as low weight, high stiffness, and high mechanical and physical properties. Inheriting such an outstanding combination of specifications, they are nowadays considered as the promising materials in the aerospace and biomedical industries. However, the presence of high abrasive reinforcing particles in MMCs leads to severe manufacturing issues. Due to the tool-particle interactions which occur during the machining of MMCs, high tool wear and poor surface finish are induced and those elements are considered as the main drawbacks of cutting MMCs. In this study, dry turning experiments were conducted for two different inserts and coated carbide on a bar of titanium metal matrix composite (Ti-MMC). Semi-finishing machining is operated with cutting parameters based on the tool supplier's recommendations which were not fully optimized. The maximum flank wear length (VBBmax) was selected as the tool wear criteria.
2013-09-17
Journal Article
2013-01-2232
Zdzislaw H. Klim, Martin Zeppetelli, Michel Saad
The hydraulic actuators are used to power flight control surfaces of the aircraft and to ensure surface movement. A system of two or three actuators is usually designed depending on the surface and intuitively these actuators are considered as a redundant architecture from a reliability and functionality point of view. The proper reliability modeling of the system of actuators must consider the system's functionality and design constraints for the remaining available actuator hinge-moment in the event of a partial or total actuator failure. As a result, this will affect the reliability assessment of that design. Furthermore, this system of actuators is also designed to provide a second function involving an assurance of the surface stiffness and damping. Generally, this second function does not require necessarily the same number of available actuators in order to be fully provided.
2013-09-17
Technical Paper
2013-01-2121
Zdzislaw H. Klim, Adam Skorek
The safe operation of technical systems is a mandatory basic requirement for the entire industry. However, there are specific industries where the safety of operation is critical and is considered as a required characteristic. These types of industries include the aerospace, military, civil aviation, nuclear power, as well as chemical and automotive industries. Safety is everyone's responsibility but engineering plays the most important role in the course of achieving a safe product operation. There are two specific phases of the product life cycle where the safety characteristics should be addressed by engineering activities: the design and development and operation phases. Modern engineering education is oriented to provide future engineers with a sufficient background to be able to Conceive-Design-Implement-Operate.
2012-10-22
Technical Paper
2012-01-2141
Vintila Canciu, Alexandru Canciu
Traceability has always been considered a useful but costly activity and different methods have been applied to reduce this cost. The current paper constitutes an attempt to improve these methods by introducing an optimal traceability process to be used in the context of RTCA DO-297 “Integrated Modular Avionics (IMA) Development Guidance and Certification Considerations”. The paper starts by comparing the definitions of traceability from DO-297 and the related development guidelines (i.e. ARP4754A, DO-254 and DO-178B). The paper continues by classifying the traceability methods recommended by the guidelines and introducing a performance criterion for optimal traceability based on category theory. This criterion addresses the possibility of information loss present in the current traceability methods. The paper proposes an optimal traceability process (i.e. that guarantees that information is not lost) and exemplifies it. The paper ends by recommending further enhancements.
2012-10-22
Technical Paper
2012-01-2104
Mitchell Miller, Janice Meraglia, James Hayward
Proposes adoption of an industry standard marking protocol to assure the authenticity of high-reliability electronics. The protocol is seen as a key ingredient in the industry's effort to control counterfeit electronic parts escapes. The specifications of the marking protocol have been informed by the experience of the authors, who are currently participating in a DNA marking program mandated by the Defense Logistics Agency. The protocol would set out these criteria for an effective marking program: Simplicity Proven uncopyability Reportability: transparency and ease of oversight Legal validity: empowering of law enforcement Quick ramp-up and seamless implementation Extreme fidelity and absolute character of results - reliability of the mark at a very high level Universal adoption
2012-10-22
Technical Paper
2012-01-2184
Michael Baldwin
This paper will illustrate how the increasing electrical demands to power military and aerospace applications can successfully be met by high performance electromechanical relays. To meet these higher demands engineering compatibility must be properly understood between the intended application and relay switching performance parameters. With high performance electromechanical relays continuing to play a critical part in military and aerospace applications it is more important than ever before that engineers capture all of the military and aerospace electrical power requirements. A critical area within powering military and aerospace systems is capacitive load switching. Capacitive loads can generate high current levels that are transient in duration and adversely affect the relay at the component level and the military or aerospace applications at the higher systems levels. As capacitance increases the amplitude and duration of the current transient also increase.
2012-10-02
Technical Paper
2012-36-0244
Henrique Martinni Ramos de Oliveira, Estephanie Nobre Dantas Grassi, Pedro Augusto Sobral Espindola, Carlos Jose de Araujo
Shape memory alloys (SMA) have a unique behavior due to a reversible phase transformation between two solid crystalline structures: martensite (low temperature and low stiffness phase) and austenite (high temperature and a higher stiffness phase). This transformation can occur either as a result of temperature change or mechanical stress load, both above characteristic critical values of these materials. Due to the reversible nature of this phenomenon, direct transformation occurs when austenite transforms into martensite and reverse transformation when martensite transforms into austenite. The latter is induced by raising the temperature and it is this process that occurs during the generation of significant associated forces through the undergone deformation recovering of the material, being of fundamental importance for the use as actuators.
2012-09-10
Technical Paper
2012-01-1883
Don Jasurda
Quality itself is no longer a differentiator among aerospace manufacturers. High quality is expected and achievable. With enough time and money, any manufacturer can turn around a high-quality product. Around the globe, the focus of manufacturing quality is shifting to a discussion about the cost of quality and how to manage it. The question being asked by manufacturers is no longer how to achieve quality, but how to achieve it within cost and time constraints. The aerospace manufacturer that can achieve quality with the least expense, while producing products the fastest, is the one that will win in today's tough, global market. This paper will describe the “closed-loop” approach to dimensional engineering, utilizing virtual simulations and tolerance analyses, and how such an approach can link cost factors with tolerance adjustments so that users have the data they need to make the most strategic business decisions regarding the balance between quality and cost.
2012-09-10
Journal Article
2012-01-1881
Niklas Bjorlingson, Mattias Rengstedt
The use of advanced battery tools substantially improves both ergonomics and quality in aircraft assembly. The Atlas Copco STB family of tools has built-in transducers, which allows the tool to meet the high demands for tightening accuracy requested by the aircraft industry. STB offers a variety of radio communication protocols including Bluetooth and Wi-Fi to allow torque data to be transmitted to a control unit that stores it for analysis. To trace stored torque data back to the application i.e. traceability, has turned out to be the desired process for critical fasteners in e.g. wing junction. The handheld STB tool can also be setup to operate without a control unit, in case there is no need to transmit and store torque data. For structural fasteners which are widely used all around the aircraft, this way of operating provides added value over a pneumatic clutch tool because of the improved accuracy in tightening as well as cost savings for energy and improved ergonomics.
2011-10-18
Technical Paper
2011-01-2766
Laure Jaeger, Christian Gogu, Stéphane Segonds, Christian Bes
Abstract The robust optimization allows designing an optimal system whose performances are insensitive to uncertainties. On the other hand reliability based optimization determines a minimum level of reliability but makes no guarantee regarding the performance sensitivity to uncertainties. In this paper a method combining both approaches is developed and is illustrated by an application to preliminary aircraft design. Uncertainties are taken into account through a probabilistic approach stemming from the use of historical data of aircraft (features, performances, etc.). Firstly, one shows that taking into account uncertainties with a constant standard deviation from the residual errors of the database, generates non-physical results because it leads to too large uncertainties in some regions.
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].
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