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2015-09-29
Technical Paper
2015-01-2757
Deepak Anand Subramanian, Nithya Sridhar, Obuli Karthikeyan N, Srinivasa Chandra V
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
Technical Paper
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.
2015-09-27
Technical Paper
2015-01-2692
Giulia Garello, Niccolò Patron, Pietro Buonfico
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
Technical Paper
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.
2015-09-27
Technical Paper
2015-01-2670
Achim Reich, Dr. Angelo Sarda PhD, Dr. Martin Semsch PhD
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.
2015-09-15
Technical Paper
2015-01-2608
Joshua Cemenska, Todd Rudberg, Michael Henscheid
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.
2015-09-15
Technical Paper
2015-01-2499
Perla Maiolino, Richard A. J. Woolley, Atanas Popov, Svetan Ratchev
Assembly and manufacture of aerospace structures, in particularly legacy products, relies heavily on the skill or rather craftsmanship of the human operator. Compounded by low volume rates the implementation of a fully automated production facility may not be cost effective. A more efficient solution is a mixture of both manual and automated operations but herein lays an issue of human error when stepping through the build from manual operation to an automated one. Some inline quality checking must take place, machine vision is an obvious choice yet it can be plagued with problems in shop floor environments. Here we demonstrate a robust solution using a low cost 3D scanner comprising of IR enabled adaptive depth detection. The system checks the quality of manually assembled sub components before automated robot controlled operations are undertaken.
2015-09-15
Technical Paper
2015-01-2546
Sylvain Delrieu
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
2015-01-2553
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
Technical Paper
2015-01-2552
Helmut Plankl
This presentation will give an actual view on concepts and implementations to improve the efficiency of Ground Test Facilities for Combat Air Systems at Airbus Defence and Space. The presentation will start with a short introduction in the structure of the Airbus Group. Leading to Airbus Defence and Space business line Military Aircraft. As part of engineering, the organisations "Flight Test and Operations" and "Rig Operation" combine overall expertise in the test concept definition, test program management and execution of rig integration, ground and flight testing. "Rig Operation" is primarily responsible for the development, design, operation and support of Ground Test Facilities for design validation and verification (V&V) within integration of Combat Air Mission Systems.
2015-09-15
Technical Paper
2015-01-2385
Richard C. Millar
At the Naval Postgraduate School, the faculty & students have exploited the flexibility and cost effectiveness of UAS as experimental flight test platforms, but this has recently been impeded by a ruling that these flights must comply with the NAVAIR interim flight clearance (IFC) process and procedures. The research project described and discussed in this presentation & publication was initiated to rapidly come to grips with this problem, identify mitigations and demonstrate a method to satisfy the need of all parties. The initial phase exposed mismatches in NPS design & analysis capability and the requirements of the contrasting developmental modes and resources, but also highlighted the procedural flexibility of the UAS developmental model. The need for a more effective but suitable process for managing small UAS flight test risks was recognized.
2015-09-15
Technical Paper
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
2015-01-2548
Andreas Himmler
Hardware-in-the-loop (HIL) testing is regarded as the tried-and-tested method for function, component, integration and network tests for the entire system. It is indispensable in the software development process for control units and has been an integral part of numerous companies’ development process for years. This holds especially for model based design. Since all the time HIL testing is applied, users continuously optimized their processes. This reflects the need to adopt testing processes to changing conditions, which may be imposed by industry changes. A well-known fact is the division of tasks between different sites of a single company or between the system integrator and its suppliers. Thus, companies, departments or teams are often located in different buildings, towns or even countries. This division of tasks imposes a challenge for the integration testing of systems, since there are significant interdependencies between the controls of aircraft systems.
2015-09-15
Technical Paper
2015-01-2550
Kiran Thupakula
Methodologies for maximizing utilization of Test Lab Kiran Thupakula, Sensors and Integrated Systems UTC Aerospace Systems, Bangalore kiran.thupakula@utas.utc.com 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 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
2015-01-2620
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
Technical Paper
2015-01-2525
Dave Duncan
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. 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 or Software for the system, thus timely identification will limit risks. The implementation of this testing is treated no differently than any other. The key here is to know the scope of the tests and plan accordingly. The understanding that the test environment will need to be capable of generating these “abnormal operating conditions” is key to properly planning for and establishing the infrastructure needed.
2015-09-15
Technical Paper
2015-01-2524
Srikanth Gampa
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. 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
2015-01-2434
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
2015-01-2454
Patrick H. Browning, Wade Huebsch
The design and testing of small unmanned aerial vehicle (SUAV) prototypes can provide numerous difficulties when compared to larger aircraft. In many cases, it is desirable to have a better understanding of the typically low Reynolds number aerodynamics and stability characteristics prior to completion of the final SUAV design. This paper describes to 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
2015-01-2551
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.
2015-09-06
Technical Paper
2015-24-2517
Piotr Bielaczyc, Joseph Woodburn, Andrzej Szczotka
The particulates in vehicular exhaust are now under great scrutiny and are subject to legislative limits in many cases. In the EU, direct injection spark ignition (DI SI) engines running on petrol now have limits for particulate emissions set for both mass and number. It is widely acknowledged that current legislative laboratory test procedures in many ways represent a best-case scenario – more aggressive driving cycles and less favourable ambient conditions 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. Cold start events are challenging for internal combustion engines for various reasons, with multiple emissions impacts for all types of automotive engines.
2015-09-06
Technical Paper
2015-24-2510
Jan Czerwinski, Pierre Comte, Martin Güdel, Andreas Mayer, Jacques Lemaire, Felix Reutimann, Adm Heinz Berger
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 NO2 in the ambient air of several cities. This is in spite of lowering NOx. NO2 is much more toxic than 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 are changing along the gas way of the exhaust- and the CVS systems. For legal measurements of NO2 a WLTP-DTP subgroup proposed different combinations of NOx-analyzers and analysis of NO and NOx. Some of these setups were tested in this work. The investigated WLTP – NO2-measuring methods have been found as useful tools to estimate the NO2-levels and there were no indications of reactivity at these low concentration levels.
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 different road gradient: the first pattern is quite flat, the second is in an area with variable altitude and 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 (PEM) connected also to the Engine Control Unit for saving the main engine parameters and a 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
2015-24-2391
Dimitris Tsokolis, Stefanos Tsiakmakis, Georgios Triantafyllopoulos, Anastasios Kontses, Zisis Toumasatos, Georgios Fontaras, Athanasios Dimaratos, Biagio Ciuffo, Jelica Pavlovic, Alessandro Marotta, Zissis Samaras
The present paper describes the development of a standardized modelling approach to simulate the effect of the new Worldwide harmonised Light duty Test Procedure (WLTP) on the certified CO2 emissions of light duty vehicles. The European fleet has been divided into a number of representative segments based on specific vehicle characteristics and technologies. Representative vehicles for each segment were chosen. A test protocol has been developed in order to generate the necessary validation data for the simulation models which were developed subsequently. A standardized modelling procedure was adopted, in order to minimize the flexibilities and sources of uncertainty, which was based on the development of a reference "template model" to be used in the study. Subsequently, vehicle models were developed using AVL Cruise simulation software based on the abovementioned template model.
2015-09-06
Technical Paper
2015-24-2524
José Lujan, José V. Pastor, Héctor Climent, Manuel Rivas
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. Effects of different boundary conditions on turbocharger test bench tests and how they affect the discharge coefficient measurement are also presented.
2015-09-06
Technical Paper
2015-24-2542
Carmelina Abagnale, Salvatore Strano, Massimo Cardone, Paolo Iodice, Mario Terzo, Giovanni Vorraro
The paper describes the development of an innovative test rig for the evaluation of e-bikes in terms of energetic performances, pollutant emissions and control system. The test rig has been realized starting from a commercial cyclist training system and operating on it substantial modifications. The test rig is able to reproduce an aforethought route or paths acquired during road tests. Through the installed sensors and data acquisition system, it is possible to measure the performance of the e-bike in terms of instantaneous power and speed. The experimental test rig can simulate the resistant torque of a predetermined track and allows to test and optimize the control strategy available on the electronic control unit (ECU). A fundamental feature of the system is constituted by the possibility of adopting a hardware in the loop approach for the testing of the e-bike and of its control.
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.
2015-07-29
Article
SAKOR Technologies supplies a test system for the Dream Chaser atmospheric flight control system, serving as a spacecraft emulator to test overall system performance.
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