Display:

Results

Viewing 1 to 30 of 23661
2015-09-29
Technical Paper
2015-01-2757
Deepak Anand Subramanian, Nithya Sridhar, N. Obuli Karthikeyan, V. Srinivasa Chandra
The Indian automotive sector is experiencing a major shift, focusing predominantly towards the levels of quality, reliability and comfort delivered to the customer. Since the entry of global players into the market, there is a rising demand for timely product launches with utmost priority to reliability. In any vehicle, suspension plays a critical role in transferring the road inputs onto the vehicle components, therefore, responsible for both ride comfort and load transfer. Engine mount, being an integral part of this system, takes care of isolating the inertial forces between the engine and the chassis. This project details on how testing can aid in reducing the launch time as well as ensuring desired degree of reliability. It proposes a methodology to formulate a life model for the engine mount considering various combinations of predictor parameters affecting its performance over its design life.
2015-09-29
Journal Article
2015-01-2758
Zhigang Wei, Robert Rebandt, Michael Start, Litang Gao, Jason Hamilton, Limin Luo
Bench testing is commonly used to construct fatigue design curves, which are used for the durability and reliability assessment of engineering components subjected to cyclic loading. Several criteria, such as R90C90 and R99C50, are widely used in automotive industry to construct fatigue design curves for a typical testing sample allocation, i.e. two stress/load levels and 6 data points at each stress/load levels. In order to reduce the test sample size and associated testing cost, recently, a Bayesian statistics based design curve construction method has been successfully developed. The Bayesian method is based on a large amount of reliable historical fatigue test data, the associated probabilistic distributions of the mean and standard deviation of the failure cycles, and an advanced acceptance-rejection resampling algorithm.
2015-09-29
Journal Article
2015-01-2768
Houshun Zhang, James Sanchez, Matthew W. Spears
Abstract In 2015 the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Transportation's National Highway Traffic Safety Administration (NHTSA) proposed a new steady-state engine dynamometer test procedure by which heavy-duty engine manufacturers would be required to create engine fuel rate versus engine speed and torque “maps”.[1] These maps would then be used within the agencies' Greenhouse Gas Emission Model (GEM)[2] for full vehicle certification to the agencies' proposed heavy-duty fuel efficiency and greenhouse gas (GHG) emissions standards. This paper presents an alternative to the agencies' proposal, where an engine is tested over the same duty cycles simulated in GEM. This paper explains how a range of vehicle configurations could be specified for GEM to generate engine duty cycles that would then be used for engine testing.
2015-09-27
Technical Paper
2015-01-2692
Giulia Garello, Niccolò Patron, Pietro Buonfico, Luca Martinotto
Nature of braking friction is extremely complex and a deeper understanding of the physical mechanisms that govern the energy dissipation at the interface of friction pair is an important tool to create an even deeper knowledge of tribological behavior of friction material. Friction brakes need to transform kinetic energy into heat: a complete knowledge of thermal effects during this process in every brake component is an essential part of brake design. As referred to brake pads, the analysis of dyno testing data highlighted experimental evidences related to thermo-mechanical effects, such as the different wear resistance capabilities of material classes (NAO and Low Steel). Tribological characteristics are not constant under all testing conditions and they strongly depend on temperature being the direct consequence of kinetic energy dissipation. The aim of this work is to explain the relation between wear and energy for different type of friction materials.
2015-09-27
Journal Article
2015-01-2670
Achim Reich, Angelo Sarda, Martin Semsch
Residual brake torque (RBT) is generated in disc brakes as a result of contact (dynamic friction) between brake disc and brake pads when the braking system is not actuated. Among the negative implications of RBT are, notably, dispensable additional fuel consumption as well as increased pad wear, which can also unfold as uneven along the pads` surfaces. The paper is based on extensive knowledge acquired through manifold measurement-based studies and contains a comprehensive assessment of the main topics related to the subject. Aiming to provide an overview about the motivation and importance of efforts to reduce RBT, effects on the environment as well as on consumption of resources are contemplated both within a general frame and for a number of selected specific cases.
2015-09-27
Journal Article
2015-01-2694
Cheng Ruan, Lijun Zhang, Dejian Meng
Research Objective During light to moderate braking at high speed, the local high temperature phenomenon can be observed on the brake disc surfaces, known as hot spots. The occurrence of hot spots will lead to negative effects such as brake performance fade, thermal judder and local wear, which seriously affect the performance of vehicle NVH. In this paper, based on the bench test of a ventilated disc brake, the basic characteristics of hot spots is obtained and the evolution process of temperature field and disc deformation is analyzed in detail. Methodology A stop brake bench test under different initial speeds and brake pressures is completed on a Link Model 3900 brake dynamometer. The temperature field and deformation of the disc surface is obtained via inferred thermal camera and non-contact displacement sensors. The space distribution characteristic and time evolution characteristic of disc temperature field and deformation is analyzed.
2015-09-15
Technical Paper
2015-01-2620
Philip Van Baren
Random vibration control systems produce a PSD plot through a method of averaging the FFT of individual frames of data. Modern controllers can set the DOF, or number of frames in the averaged PSD signal. The PSD is a way to present a random signal with high excursions from the mean in a format that makes it easy to determine the validity of the test. This process takes time as many frames of data are collected to generate the PSD and the test can appear to be out of tolerance until the controller has enough data. A random signal that achieves an in-tolerance condition immediately after starting or during level changes can create dangerous over or under test conditions within specific frequency bands and should be avoided. Take-Away 1: What is Random? Take-Away 2: Why is it represented as a PSD? Take-Away 3: How can you minimize out of tolerance events?
2015-09-15
Journal Article
2015-01-2499
Perla Maiolino, Richard A. J. Woolley, Atanas Popov, Svetan Ratchev
Abstract The assembly and manufacture of aerospace structures, in particular legacy products, relies in many cases on the skill, or rather the craftsmanship, of a human operator. Compounded by low volume rates, the implementation of a fully automated production facility may not be cost effective. A more efficient solution may be a mixture of both manual and automated operations but herein lies an issue of human error when stepping through the build from a manual operation to an automated one. Hence the requirement for an advanced automated assembly system to contain functionality for inline structural quality checking. Machine vision, used most extensively in manufacturing, is an obvious choice, but existing solutions tend to be application specific with a closed software development architecture.
2015-09-15
Technical Paper
2015-01-2454
Patrick H. Browning, Wade Huebsch
Abstract The design and testing of small unmanned aerial vehicle (sUAV) prototypes can provide numerous difficulties when compared to the same process applied to larger aircraft. In most cases, it is desirable to have a better understanding of the low Reynolds number aerodynamics and stability characteristics prior to completion of the final sUAV design. This paper describes the design, construction, and operational performance of a pneumatic launch apparatus that has been used at West Virginia University (WVU) for the development and early flight testing of transforming sUAV platforms. Although other launch platforms exist that can provide the safe launch of such prototypes, the particular launch apparatus constructed at WVU exhibits unmatched launch efficiency, and is far less expensive to operate per shot than any other launch system available.
2015-09-15
Technical Paper
2015-01-2546
Sylvain Delrieu
Abstract To perform a complete aircraft certification plan, civil aviation test centres use specific flight test installations and ground test means. In this scope tests specialists operate ground test means which have a generic name Laboratory Tests Means (LTM) to validate aircraft functions. Today these functions are becoming more and more complex, moreover certification deadlines and tests campaign costs are becoming increasingly challenging and demand LTM use optimization. In this context current LTM development approach is no longer suitable to cover these new constraints. Currently LTMs start to be designed when testing strategy for a new aircraft is defined and design is quite specific. Drawbacks of such an approach are: tunnel effect for LTM development, no simple sharing of testing resources, LTM reuse is not easy, LTM upgrade requires re-engineering and many LTMs have to be maintained even if only partially used.
2015-09-15
Technical Paper
2015-01-2548
Andreas Himmler
Abstract Hardware-in-the-loop (HIL) testing is indispensable in the software development process for control units and has been an integral part of the software development process for years. Large HIL systems for integration tests are used to test the correct behavior of distributed functions and the communication between the control units. The vast development programs that are involved require building duplicates of such test systems or parts of them, due to the fact that the tasks are distributed between different companies or different departments within a company. However, there is an alternative to duplicating a test system. Instead of using a cloned system, coupling HIL systems over large distances is an alternate approach. This paper presents what requirements this coupling must fulfill and and describes a path-breaking method to fulfill them. In addition, results of an implementation are shown.
2015-09-15
Journal Article
2015-01-2390
Georges Ghazi, Ruxandra Botez, Joseph Messi Achigui
During aircraft development, mathematical models are elaborated from our knowledge of fundamental physical laws. Those models are used to gain knowledge in order to make decisions in all development stages. As engine model is one of the most important items in aircraft simulation, this paper presents a methodology to obtain a generic technique that can be used to predict the net thrust value of the engines for the Cessna Citation X. The proposed methodology is divided in two steps. The first step is focused on the estimation of the net thrust value in steady state. The goal of this section is to obtain a model that can predict the maximum thrust of the turbofan engine at different flight conditions in terms of altitude and Mach number. To do this, semi-empirical equations available in the literature and the least squares method are used to identify the coefficients of the proposed model.
2015-09-15
Technical Paper
2015-01-2434
Tian Lirong, Mu Ming
Abstract: Chinese aviation industry is now making great efforts in developing civil aircraft, as a result, more opportunities for Chinese companies to be involved in these programs, but Chinese companies are lack of experience in this area, certification is one of the challenges for them,so they are expected to be more competitive in design and certification. ACTRI (Aeronautical Computing Technique Research Institute) is a airborne computer supplier in China, to be able to develop electronic equipment for civil aircraft, the company has being working on processes improvement including the system process based on ARP4754 since 2008. This paper describes the customized system process in Chinese context.
2015-09-15
Technical Paper
2015-01-2551
Ephraim Suhir, Alain Bensoussan
In some today’s and future optoelectronic packaging systems, including those intended for aerospace applications, the package (system’s component containing active and/or passive devices and interconnects) is placed (“sandwiched”) between two substrates, which, in an approximate analysis, could be considered identical. Such a system is bow-free. This might be an important merit that could be helpful in maintaining high coupling efficiency in warpage-sensitive optical devices. The highest thermal stresses in such a tri-component (one inner and two outer components) bi-material (the composite material of the inner component - package and of the material of the outer components - substrates) assembly occur at low temperature conditions, are caused by the thermal contraction mismatch of the dissimilar materials of the assembly components and include normal stresses acting in the cross-sections of the components, and interfacial shearing and peeling stresses.
2015-09-15
Technical Paper
2015-01-2552
Helmut Plankl
Abstract The paper will start with a short introduction to the structure of the Airbus Group, before addressing the Airbus Defence and Space business line Military Aircraft. The Rig Operation department for airborne solutions within this organisation is responsible for the development, design, operation and support of ground test facilities and test support systems, which are used for design validation and verification of civil and military air systems. The main part of this document will start with a typical sequence of tests in our Test Centre. The presentation will then focus on some advanced methods used during the qualification of test equipment and to improve the efficiency of ground test facilities in terms of cost, time and risk reduction. The next topic is tool-based rig management and control, beginning with test preparation and test shift planning and also covering aspects of configuration control, automatisation of test facilities and support of the test report.
2015-09-15
Technical Paper
2015-01-2525
Dave Duncan
Abstract The verification of Robustness is conceptually simple, once the reasonable set of “abnormal operating conditions” has been established. During testing those conditions are created and the FPGA/CEH response is noted. Depending upon system requirements, sometimes the FPGA/CEH response need not be “to work normally” but should at a minimum return to normal operation once normal conditions are reestablished. Part of the analysis is to establish acceptable FPGA/CEH responses to the “abnormal operating conditions”. Some of the acceptable responses may actually affect the LRU/CCA hardware performance or software functions hosted on the system, an early identification of such interdependence is essential for the planning of robustness testing. The test cases implementing robustness testing conform to the same constraints and pedigree as any requirements based test case. The key here is to know the scope of the tests and plan accordingly.
2015-09-15
Technical Paper
2015-01-2550
Kiran Thupakula
Abstract In Aerospace Industry, the major challenge is to meet the safety and quality of subsystem / system elements to comply with the standards defined by regulatory authorities for product certification. Engineering test labs are created to provide such precision oriented test platforms ranging from component level to fully integrated test labs/test systems, standalone or distributed network. Even after massive initial capital investment and with the evolution of technologies followed by principles of practice in establishing test facilities, industry is facing open challenges in meeting the performance parameters like productivity, optimum usage, accessibility, monitoring, control and ease of maintenance to list a few. It's very important to standardize the test facilities to optimize time to market and reduce the product cost.
2015-09-15
Technical Paper
2015-01-2524
Srikanth Gampa
Abstract Multi core platforms offer high performance at low power and have been deemed as future of size, weight and power constrained applications like avionics safety critical applications. Multi core platforms are widely used in non-real time systems where the average case performance is desired like in consumer electronics, telecom domains. Despite these advantages, multi core platforms (hardware and software) pose significant certification challenges for safety critical applications and hence there has been limited usage in avionics and other safety critical applications. Many multicore platform solutions which can be certified to DO-254 & DO 178B Level A are commercially available. There is a need to evaluate these platforms w.r.t certification requirements before deploying them in the safety critical systems thereby reducing the program risks. This paper discusses the advantages of multi core platforms in terms of performance, power consumption and weight/size.
2015-09-15
Technical Paper
2015-01-2567
Dushyant Kaliyari, Khadeeja Nusrath TK, Jatinder Singh
Abstract Aerodynamic database update from the flight tests using system identification techniques is a crucial tool for the development of control laws and high fidelity simulators. For the certification of aircraft under test, aero-database needs to be validated from flight tests throughout the flight envelope and also to certain levels beyond the envelope boundaries. Validation of aero-database close to envelope boundaries entails additional complexities which necessitates careful handling of flight data identification and update process. This paper discusses the approach adopted for aero-database update and flight clearance, followed by a discussion on the issues relevant in the extreme flight test regimes, such as, flow angle accuracy at higher angles-of-attack, center-of-gravity variation with fuel pitch angle for high-g maneuvering conditions and inaccuracies in Mach number at transonic speeds.
2015-09-15
Journal Article
2015-01-2385
Richard C. Millar
Abstract Unmanned aviation systems (UAS) acquired for US Navy for military roles are developed in the context of NAVAIR's rigorous and well-established policies, procedures and processes employed in the acquisition and development of manned aircraft. A key process is the preparation and approval of interim flight clearances (IFC) prior to flight test to ensure the aircraft is airworthy and thus safe to operate. Due to the perceived risks of UAS experimental flight test, the use of this process has been mandated for all Navy organizations, including use of commercially available UAS in research projects. This policy has proved to be a challenge, impeding and discouraging the use of UAS in research and experimental projects. Currently, the cost of compliance is unaffordable and IFC preparation and approval time are inconsistent with research cycle time expectations.
2015-09-15
Technical Paper
2015-01-2553
Markus Dahlweid, Jörg Brauer, Jan Peleska
Model-based development is a well-established and widely used technique to design and implement systems by specifying the overall architecture of a system and its behavior directly in modeling tools such as Atego Modeler or Enterprise Architect. The next step forward in this process is using the same framework also for the design and specification of the tests for these systems. The RT-Tester MBT tool offers a novel approach to model-based embedded systems testing. Model-based Testing offers automated generation of test cases, test data and test procedures for model-in-the-loop, hardware-in-the-loop and system testing from UML/SysML models, which describe the intended system behavior. The presented approach offers a number of testing strategies, which can be used to tailor the generated test suites according to the indented criticality level.
2015-09-15
Journal Article
2015-01-2608
Joshua Cemenska, Todd Rudberg, Michael Henscheid
Abstract In many existing AFP cells manual inspection of composite plies accounts for a large percentage of production time. Next generation AFP cells can require an even greater inspection burden. The industry is rapidly developing technologies to reduce inspection time and to replace manual inspection with automated solutions. Electroimpact is delivering a solution that integrates multiple technologies to combat inspection challenges. The approach integrates laser projectors, cameras, and laser profilometers in a comprehensive user interface that greatly reduces the burden on inspectors and decreases overall run time. This paper discusses the implementation of each technology and the user interface that ties the data together and presents it to the inspector.
2015-09-06
Technical Paper
2015-24-2419
Riccardo Amirante, Caterina Casavola, Elia Distaso, Paolo Tamburrano
A simple, cheap and effective way of measuring the pressure inside the cylinders of internal combustion engines is proposed in this paper. It is well known that the in-cylinder pressure is one of the most significant variables describing the combustion status in internal combustion engines; therefore, if the measured value of the actual pressure in the combustion chamber is used as a feedback variable for closed loop monitoring and control techniques, it will be possible both to improve engine performances and to reduce fuel consumptions and emissions. However, to date such a pressure-based control strategy has been limited by costs, reliability and lifetime of commercially available cylinder pressure sensors. To overcome these limitations, the present paper proposes a very simple and low cost experimental device for measuring the pressure inside the combustion chamber, developed for engine control and monitoring applications.
2015-09-06
Technical Paper
2015-24-2449
Mark Aaron Hoffman, Zoran Filipi
The limited operational range of low temperature combustion engines is influenced by near-wall conditions. A major factor is the accumulation and burn-off of combustion chamber deposits. Previous studies have begun to characterize in-situ combustion chamber deposit thermal properties with the end goal of understanding, and subsequently replicating the beneficial effects of CCD on HCCI combustion. Combustion chamber deposit thermal diffusivity was found to differ depending on location within the chamber, with significant initial spatial variations, but a certain level of convergence as equilibrium CCD thickness is reached. A previous study speculatively attributed these spatially dependent CCD diffusivity differences to either local differences in morphology, or interactions with the fuel-air charge in the DI engine. In this work, the influence of directly injected gasoline on CCD thermal diffusivity is measured using the in-situ technique based on fast thermocouple signals.
2015-09-06
Technical Paper
2015-24-2504
Gerben Doornbos, Emma Adams, Per-Anders Carlsson, Daniel Dahl, Mats Laurell, Håkan Schyllander, Par Gabrielsson, Milica Folic, Ingemar Denbratt, Magnus Skoglundh
Commercial three way catalysts have limited capacity towards reducing NOx in the presence of excessive oxygen. This prevents lean-burn combustion concepts from meeting legislative emission standards. A solution towards decreasing NOx emissions in the presence of excess air is the use of a passive-SCR system. Under rich conditions ammonia is formed over an ammonia formation catalyst, the ammonia is stored in the SCR and in its turn reacts with the NOx under lean engine conditions. Here up-scaled Pt/Al2O3 and Pd/Al2O3 catalysts as well as a commercially Pd-Rh based three-way catalyst (TWC) are evaluated using both engine and further lab-scale tests. The purpose of these tests is to compare the ammonia production for the various catalysts under various lambda values and temperatures by means of engine and lab scale tests. The Pd/Al2O3 showed little sensitivity to temperature both under engine and lab scale experiments.
2015-09-06
Technical Paper
2015-24-2509
Maria Vittoria Prati, Giovanni Meccariello, Livia Della Ragione, Maria Antonietta Costagliola
The aim of this study is to investigate the parameters influencing the real driving emission monitoring with particular attention towards the influence of road gradient. For this purpose, an experimental activity was carried out with a Euro 5 Diesel light-duty vehicle, driven along two tracks of Naples characterized by a different road gradient: the first pattern is quite flat, the second includes positive (+2.9%) and negative (−3.6%) road gradient. Exhaust emissions of CO, THC, NOx, CO2 were acquired on road by using a portable emission measuring system (PEMS) connected also to the Engine Control Unit for saving the main engine parameters and to the GPS for the geographical coordinates and altitude. The acquired speed profiles were repeated on the chassis-dynamometer without simulating the road gradient.
2015-09-06
Technical Paper
2015-24-2510
Jan Czerwinski, Pierre Comte, Martin Güdel, Andreas Mayer, Jacques Lemaire, Felix Reutimann, Adm Heinz Berger
Abstract As a result of increased use of catalytic exhaust aftertreatment systems of vehicles and the low-sulfur Diesel fuels there is an increasing share of nitrogen dioxide NO2 in the ambient air of several cities. This is in spite of lowering the summary nitric oxides NOx emissions from vehicles. NO2 is much more toxic than nitrogen monoxide NO and it will be specially considered in the next legal testing procedures. There are doubts about the accuracy of analyzing the reactive substances from diluted gas and this project has the objective to show how NO2 is changing as it travels down through the exhaust- and the CVS systems. For legal measurements of NO2 a WLTP-DTP subgroup (Worldwide Light Duty Test Procedures - Diesel Test Procedures) proposed different combinations of NOx-analyzers and analysis of NO and NOx. Some of these set-ups were tested in this work.
2015-09-06
Technical Paper
2015-24-2517
Piotr Bielaczyc, Joseph Woodburn, Andrzej Szczotka
Abstract Particulate matter in vehicular exhaust is now under great scrutiny. In the EU, direct injection spark ignition (DISI) engines running on petrol now have limits for particulate emissions set for both mass and number. Current legislative test procedures represent a best-case scenario - more aggressive driving cycles and lower ambient temperatures can increase particulate emissions massively. Ambient temperature is generally the environmental parameter of most importance regarding particulate emissions from an engine, particularly for the reasonably brief periods of operation typical for passenger cars operating from a cold start. Two Euro 5 vehicles with DI SI engines were laboratory tested at three ambient temperatures on two different commercially available fuels, with particulate emissions results compared to results from the same fuels when the vehicles were tested at 25°C.
2015-09-06
Technical Paper
2015-24-2524
José Lujan, José V. Pastor, Héctor Climent, Manuel Rivas
Abstract On actual gasoline turbocharged engines it is common to use a compressor by-pass valve in order to solve the compressor surge problem when the throttle pedal position is released and closes rapidly. The paper deals with a methodology based on experiments to measure the discharge coefficient of an integrated compressor by-pass valve, to understand the possible difference between the steady flow test bench and turbocharger test bench discharge coefficient measurements. To determine if there is some compressor outlet flow field influence due to compressor blades rotation that could modify the discharge coefficient measurement, compared to the steady flow test bench measurements, a fully instrumented turbocharger was used to measure the difference between steady flow test bench and turbocharger test bench discharge coefficients results.
2015-09-06
Technical Paper
2015-24-2542
Carmelina Abagnale, Salvatore Strano, Massimo Cardone, Paolo Iodice, Mario Terzo, Giovanni Vorraro
Abstract The paper describes the development of an innovative test rig for the evaluation of e-bikes in terms of energetic performances and control system. The test rig has been realized starting from a commercial cyclist training system and suitably modified. The test rig is able to reproduce an aforethought route or paths acquired during road tests. It is possible to measure the performance of the e-bike in terms of instantaneous power and speed, by the installed sensors and data acquisition system. The experimental test rig can simulate the resistant torque of a predetermined track and it aims to test and to optimize the control strategy available on the electronic control unit (ECU). An important feature of the system is represented by the possibility to adopt a hardware in the loop approach for the testing of the e-bike and of its control. Indeed, the whole control algorithm can be implemented on a suitable controller board able to execute real time processes.
Viewing 1 to 30 of 23661

Filter