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2017-03-28
Technical Paper
2017-01-0331
Qiuren Chen, Haiding Guo, Katherine Avery, Xuming Su, HongTae Kang
Fatigue crack growth tests have been carried out to investigate the mixed mode fatigue crack propagation behavior of an automotive structural adhesive BM4601. The tests were conducted a compound CMM (Compact Mixed Mode) specimen under load control with 0.1 R ratio and 3Hz frequency. A long distance moving microscope was employed during testing to monitor and record the real time length of the fatigue crack in the adhesive layer. The strain energy release rates of the crack under different loading angles, crack lengths and loads were calculated by finite element method. The pure mode I and mode II tests show that an equal value of mode I strain energy release rate results in over ten times higher FCGR (Fatigue Crack Growth Rate) than the mode II stain energy release rate does. The mixed mode tests results show that under a certain loading angle, the mixed mode FCGR is changed by changing the load, which is contrary to the find in pure mode I and mode II tests.
2017-03-28
Technical Paper
2017-01-0371
Raju Gandikota, Amit Nair, Kurt Miller
Testing elastomeric materials that undergo large strains pose challenges especially when establishing failure criteria. The failure criterion for composites and polymers based on finite elasticity published byFeng (1) requires testing under uni-axial and bi-axial stretching modes. The classic inflation of a circular disk for bi-axial stretch mode poses stability and safety challenges. The test can also be sensitive to end constraints resulting in failure of materials at the constraints. Bi-axial stretching with a hemispherical punch is explored in this work. The bi-axial stretching allows controlled and repeatabletesting. It establishes clear and reliable failure mechanism of the material at the poles. Through a combination of testing and numerical methods, the stretch ratios and its relation to failure has been established.
2017-03-28
Technical Paper
2017-01-1672
Siddartha Khastgir, Gunwant Dhadyalla, Stewart Birrell, Sean Redmond, Ross Addinall, Paul Jennings
The advent of Advanced Driver Assistance Systems (ADAS) and autonomous driving has offered a new challenge for functional verification and validation. The explosion of the test sample space for possible combinations of inputs needs to be handled in an intelligent manner to meet cost and time targets for the development of such systems. Various test methods like VEHiL (Vehicle Hardware-in-the-Loop), Vehicle-in-the-Loop and Co-ordinated automated driving have been developed for validation of ADAS and autonomous systems. Increasingly, driving simulators are being used for testing ADAS and autonomous systems as they offer a safer and a more reproducible environment for verifying such systems. While each of these test methods serves a specific purpose, they have a common challenge between them. All of these methods require the generation of test scenarios for which the systems are to be tested.
2017-03-28
Technical Paper
2017-01-1028
Daniel Bharathy, Ganesh Paramasivam
Venting for a diesel tank is an essential requirement to keep the tank stable by breathing in during suction & breathing out the excess pressure created inside because of vaporization. Vent valves with inappropriate specs affects the rate of supply of fuel during vacuum built up of pressure resulting in tank explosion or causes damage to the user during filling. Capacity of the tank, ambient temperature, environment, Return line temperature and application are the factors contribute in finalizing the venting specification. Considering these factors, study has been done on a metal & plastic fuel tank for a commercial vehicle application. Venting specification has been finalized for both plastic & metal tanks analytically. Vent valves developed and validated to meet the functional & durability requirements.
2017-03-28
Technical Paper
2017-01-1575
Andrei Keller, Sergei Aliukov, Vladislav Anchukov
Trucks are one of the most common modes of transport and they are operated in various road conditions. As a rule, all-wheel drive trucks are equipped with special systems and mechanisms to improve their cross-country capability and overall efficiency. The usage of blocked mechanisms for power distribution is one of the most popular and effective ways to improve the off-road vehicle performance. However, the lock of differential may adversely affect the stability and control of vehicle because of the unobvious redistribution of reactions acting on wheels, which consequently leads to poor performance and safety properties. Problems of rational distribution of power in transmissions of all-wheel drive vehicles, as well as research in the field of improving directional stability and active safety systems are among the priorities in modern automotive industry.
2017-03-28
Technical Paper
2017-01-1556
Jianbo Lu, Li Xu, Daniel Eisele, Stephen Samuel, Matthew Rupp, Levasseur Tellis
The paper presents an advanced yaw stability control (AYSC) system that uses a centralized inertial measurement unit (IMU) to measure the 6 DOF motions of a vehicle and uses the enhanced vehicle states to improve the effectiveness of the traditional electronic stability control (ESC) systems. The MEMS based IMU has nowadays been widely used in consumer electronics, such as smart phones, and its cost has been significantly reduced, which makes it feasible to roll out IMU for ESC type of systems. The additional info from an IMU helps improve the sensing capability of a vehicle, which in turn leads to refined stability control commands for AYSC such that the better control performance than the traditional ESC can be achieved (w.r.t. the real world driving scenarios). Vehicle tests will be used to show the improved control performance.
2017-03-28
Technical Paper
2017-01-0276
Lev Klyatis
This paper considers the situation in the laboratory testing: different stress types and accelerated testing, including accelerated reliability/durability testing, accelerated life testing, reliability testing, proving grounds, vibration, temperature, voltage, humidity, and others. In comparison with field situation, most of these testing simulate only one or part of the field input influences. One uses often not accurately the theory of physics-of-degradation process or failures for comparison of the field results with laboratory results. Thos situation will be considered with practical examples. It will be demonstrated that often used laboratory testing does not offer the possibility for successful prediction of product performance during service life As a result, there are many complaints, recalls, less profit than was predicted during design and manufacturing. It will be shown how one can improve this situation..
2017-03-28
Technical Paper
2017-01-1461
Sanketh Gowda, Anindya Deb, Goutham kurnool, Clifford Chou
Adhesively bonded steel hat section components have been experimentally studied in the past as a potential alternative to traditional hat section components with spot-welded flanges. One of the concerns with such components has been their performance under axial impact loading as adhesive is far more brittle as compared to a spot weld. However, recent drop-weight impact tests have shown that the energy absorption capabilities of adhesively bonded steel hat sections are competitive with respect to geometrically similar spot-welded specimens. Although flange separation may take place in the case of a specimen employing a rubber toughened epoxy adhesive, the failure would have taken place post progressive buckling and absorption of impact energy.
2017-03-28
Technical Paper
2017-01-0135
Jose Grande, Julio Abraham Carrera, Manuel Dieguez Sr
Exhaust Gas Recirculation system (EGR) is an effective technique for reducing NOx emissions in order to accomplish the more and more stringent emissions standards. This system is widely use in commercial vehicle engines in which thermal loads and durability are a critical issue. In addition, the development deadlines of the new engine generations are being considerably reduced, especially for validation test phase in which costumers usually require robust parts for engine validation in the first stages of the project. Some of the most critical issues in this initial phases of program development are heavy boiling and thermal fatigue. Consequently, it has been necessary to develop a procedure for designing EGR coolers robust enough against heavy boiling and thermal fatigue in a short period of time, even when the engine calibration is not finished and the working conditions of the EGR system are not completely defined.
2017-03-28
Technical Paper
2017-01-0389
Carlo Cantoni, Giampiero Mastinu, Massimiliano Gobbi, Federico Ballo, Giorgio Previati
The durability performance of brake hoses is a crucial issue for such components. Accelerated fatigue testing of brake hoses is necessary for understanding achievable lifetime, actually computation is quite cumebersome due to the many different materials the hoses are made from. Despite SAE standards are available, accelerated testing of brake hoses subject to actual torsional and bending stresses seem important to provide relevant feedback to designers. In this paper, an innovative methodology for assessing the fatigue behaviour of brake hoses of road vehicles is proposed. A dynamic testbed is specifically designed and realised, able to reproduce the actual assembly conditions of the hoses fitted into a vehicle suspension. The designed testbed allows to replicate actual loading conditions on the brake hoses by simulating the vertical dynamics and steering of the suspension system together with brake pressure.
2017-03-28
Technical Paper
2017-01-1675
Genís Mensa, Núria Parera, Alba Fornells
Nowadays, the use of high-speed digital cameras to acquire relevant information is a standard for all laboratories and facilities working in passive safety crash testing. The recorded information from the cameras is used to develop and improve the design of vehicles in order to make them safer. Measurements such as velocities, accelerations and distances are computed from high-speed images captured during the tests and represent remarkable data for the post-crash analysis. Therefore, having the exact same position of the cameras is a key factor to be able to compare all of the values that are extracted from the images of the tests carried out within a long-term passive safety project. However, since working with several customers involves a large amount of different cars and tests, facilities have to readapt for every test mode making it difficult for them to reproduce the correct and precise position of the high-speed cameras throughout the same project.
2017-03-28
Technical Paper
2017-01-1679
Felix Martin, Michael Deubzer
The increasing complexity of automotive real-time applications, and the challenges arising with the change to multi-core processors put higher demands on the tools which are involved in the development of such systems. With tracing it is possible to record the dynamic behavior of time-critical applications and use the data to monitor safety-critical requirements. However, not all trace techniques are sufficient for this use-case. Several factors like the available hardware, bandwidth, timing accuracy, and number of traceable objects must be considered. Additionally, traces are usually not recorded on a level that is suitable for timing analysis. Hence, a transformation of the trace may be necessary. In this paper we give an overview of existing trace techniques and discuss their applicability for the timing analysis of embedded systems. We also take limitations which may be caused by existing hardware platforms into consideration.
2017-03-28
Technical Paper
2017-01-0324
Anbo Pan, Ashley Walsh, Mark Dearth, Xiao Qing Zhang
A research project was carried out to validate the target compounds that lead to customers’ complaints about interior cabin odor. The goal was to understand what the threshold sensitivity of the customer might be, in order to determine where to set internal targets for customer satisfaction. Compounds called out by the GB/T27630-2011 and TUV Rheinland Toxproof standards that have odor descriptions, odor thresholds and irritation levels were studied, and a design of experiments (DOE) was conducted. Acetaldehyde, toluene, acetone and butyraldehyde were used to conduct the odor study by reconstituting their concentration in vehicles. It is concluded that aromatics, aldehydes, and ketones have a direct relationship to odor concerns.
2017-03-28
Technical Paper
2017-01-0318
John K. George, kishore pydimarry, Jeremy Seidt, Kelton Rieske
Characterization of the plastic and ductile fracture behavior of a ferrous casting commonly used in the steering knuckle of an automotive suspension system is presented in this work. Ductile fracture testing for various coupon geometries was conducted to simulate wide ranges of stress states. Failure data for the higher stress triaxiality were obtained from tension tests conducted on thin flat specimens, wide flat specimens and axi-symmetric specimens with varying notch radii. While the data for lower triaxiality were generated from thin walled tube specimens subjected to combined axial-torsional loading and upsetting tests on cylindrical specimens. The failure envelopes for the material were developed utilizing the test data and FE simulations of the corresponding test specimens. Experiments provided the load-displacement response and the location of fracture initiation.
2017-03-28
Technical Paper
2017-01-1354
Timothy Morse, Michael Cundy, Harri Kytomaa
One potential fire ignition source in a motor vehicle is the hot surfaces of the engine exhaust system. These hot surfaces can come into contact with combustible liquids (such as engine oil, transmission fluid, brake fluid, gasoline, or diesel fuel) due to a fluid leak, or during a vehicle collision. If the surface temperature is higher than the hot surface ignition temperature of the combustible liquid in a given geometry, a fire can ignite and potentially propagate. In addition to automotive fluids, another potential fuel in post-collision vehicle fires is grass, leaves, or other vegetation. Studies of hot surface ignition of dried vegetation have found that ignition depends on the type of vegetation, surface temperature, and on the duration of contact. Ignition can occur at surface temperatures as low as 300 °C, if the vegetation is in contact with the surface for 10 minutes or longer.
2017-03-28
Technical Paper
2017-01-0319
Dae-Young Kim, Yongtak Han, Sahnghoon Shin, Hyungsub Yook
The aim of this paper is to apply an advanced fracture model and to evaluate its applicability in an automotive seat structure. A Generalized Incremental Stress-State dependent damage Model (GISSMO), which was one of the advanced fracture models implemented in LS-DYNA, was adopted as a fracture model. A description of the damage parameter identification process with material tests was introduced in this study. Generally, fracture strains are known to be dependent on the stress triaxiality, third deviatoric stress invariant (or Lode parameter), element size, temperature, and rate effect. The GISSMO adopts most of these factors, and was introduced and reported in previous works. In order to evaluate the fracture strain in various stress states, uniaxial tension, simple shear-tension, notched-tension, and biaxial tension tests were carried out.
2017-03-28
Technical Paper
2017-01-1671
Johannes Bach, Marc Holzäpfel, Stefan Otten, Eric Sax
Enhanced technological capabilities render the application of various, increasingly complex, functional concepts for automated driving possible. In the process, the significance of automotive software for a satisfactory driving experience is growing. To benefit from these new opportunities thorough assessment in early development stages is highly important. It enables manufacturers to focus resources on the most promising concepts. For early assessment, a common approach is to set up vehicles with additional prototyping hardware and perform real world testing. While this approach is essential to assess the look-and-feel of newly developed concepts, its drawbacks are reduced reproducibility and high expenses to achieve a sufficient and balanced sample. To overcome these drawbacks, new flexible, realistic and preferably automated virtual test methods to complement real world verification and validation are especially required during early development phases.
2017-03-28
Technical Paper
2017-01-1677
Bharathi Krishnamoorthy, Jacob Eapen, Santosh kshirsagar, Giri Nammalwar, Torsten Wulf, Miguel Mancilla
Automotive industry is witnessing a significant growth in the number of Electronic Control Units (ECUs) and its features owing to the focused inclination towards customer preference, comfort, safety, environmental friendliness and governmental regulations. The software components are booming as the pivotal to cater to the technology-driven trends such as diverse mobility, autonomous driving, electrification, and connectivity. This necessitates exhaustive testing to ensure quality of the system as any unpredictable failures may impose severe financial and market risk on the OEM. The industry has largely supplemented Hardware-in-the-loop (HIL) testing to manual testing considering the testing constraints posed by the latter. Automation trends complement the demand for quick yet exhaustive testing prior to the market launch.
2017-03-28
Technical Paper
2017-01-1676
Hartmut Lackner
Software systems, and automotive software in particular, are becoming increasingly configurable to fulfill customer needs. New methods such as product line engineering facilitate the development and enhance the efficiency of such systems. In modern, versatile systems, the number of theoretically possible variants easily exceeds the number of actually built products. This produces two challenges for quality assurance and especially testing. First, the costs of conventional test methods increase substantially with every tested variant. And secondly, it is no longer feasible to build every possible variant for the purpose of testing. Hence, efficient criteria for selecting variants for testing are necessary. In this contribution, we investigate the cost drivers of testing multivariable systems and define novel criteria to systematically sample variants for the purpose of testing. The presented criteria reduce the test effort by means of tested variants as well as executed test steps.
2017-03-28
Technical Paper
2017-01-1467
Ashok Mache, Anindya Deb, Clifford Chou
There has been a keen interest in recent times on implementation of lightweight materials in vehicles to bring down the unladen weight of a vehicle for enhancing fuel efficiency. Fiber-reinforced composites comprise a class of such materials. As sustainability is also a pre-occupation of current product development engineers including vehicle designers, bio-composites based on natural fibers are receiving a special attention. Keeping these motivations of lower effective density, environment friendliness and occupational safety in mind, woven jute fabric based composites have been recently studied as potential alternatives to glass fiber composites for structural applications in automobiles. In the past, mechanical characterization of jute-polyester composites were restricted to obtaining their stress-strain behaviors under quasi-static conditions.
2017-03-28
Technical Paper
2017-01-0130
Phillip Bonkoski, Amey Y. Karnik, Adrian Fuxman
Control of vehicle powertrain thermal management systems is becoming increasingly challenging as the number of thermal system components is growing. Thermal management using model predictive control (MPC) creates a suitable framework to account for actuator and temperature constraints, and leverage potential preview information that may be available from connected vehicles. In previous SAE publications (2015-01-0336, 2016-01-0215), we have proposed the control framework for robust MPC formulation and provided both simulation and powertrain thermal lab test results. In this work, we discuss the controller deployment in the vehicle; where validation is done in both real world road driving and on a chassis dynamometer in a wind tunnel tests. The vehicle test results were used to systematically refine the desktop-calibration for the MPC, and these refinements will be explained in the paper.
2017-03-28
Technical Paper
2017-01-0275
Obuli Karthikeyan N, Prajitha N, SethuMadhavan P, Srinivasa Chandra V
As the technology gets upgraded every day, automotive manufacturers are also paying more attention towards delivering a highly reliable product which performs its intended function throughout its useful life without any failure. To develop a reliable product, functional and durability testing is not only sufficient rather it should undergo various types of stresses at different levels, to identify its potential modes of failure. By reliability testing, most of the failure modes of a component can be analyzed and eliminated in the design stage itself, prior to production. In this paper, electrical relay of a commercial vehicle was taken up for study to analyze the causes for field failure and to estimate its reliable life in the customer operating conditions. Few of the field failure samples were tested for its performance characteristics with typical testing protocol and strip out experiment was carried out to analyze the various failure modes.
2017-03-28
Technical Paper
2017-01-1678
Joseph Antony John Selvaraj, Sivapalan Balanayagam
Modern Instrument Panel Clusters (IPC) are equipped with thin film transistor (TFT) based displays. Contrary to conventional IPCs with hard gauges and liquid crystal diode (LCD) displays, TFT displays offer versatile usage of display area with soft gauges, reconfigurable menus, tell tales, graphics and warning messages etc., At the same time, the number of possible screen combinations become huge and thereby display validation turn out to be one of the complex and time consuming tasks in IPC validation. The task becomes even more complex when change requests are to be incorporated during final phases of development stage. This paper provides a novel solution that helps to validate late changes with minimum effort and maximum accuracy.
2017-03-28
Technical Paper
2017-01-1683
Adit Joshi
Software for autonomous vehicles is highly complex and requires enormous amount of vehicle testing to achieve a certain level of confidence in safety, quality and reliability. According to the RAND Corporation, a 100 vehicle fleet running 24 hours a day 365 days a year at a speed of 40 km/hr, would require 17 billion driven kilometers of testing and take 518 years to fully validate the software with 85% confidence [1]. In order to reduce cost and time to accelerate autonomous software development, Hardware-in-the-Loop (HIL) simulation is used to supplement vehicle testing. For autonomous vehicles, path following and trajectory tracking controls are an integral part for achieving lateral control. Combining the aforementioned concepts, this paper focuses on a real-time implementation of a path-following lateral controller, developed by Freund and Mayr [2].
2017-03-28
Technical Paper
2017-01-0393
Keunsoo Kim
The fuel tank should keep the fuel stably at any vehicle driving condition but sometimes, the fuel tank can’t store fuel stably due to crack because the vehicle is driven at the various environmental conditions . In case of extreme hot ambient driving condition, the fuel tank pressure is increased because of fuel boiling. In case of normal ambient temperature, before fuel boiling and large engine purge condition. The fuel tank pressure is decreased. The repetitive excessive fuel tank pressure change will lead to damage the fuel tank. The fuel tank crack can lead to fuel leakage from the fuel tank that can lead to damage the vehicle such as fire. Until now, the analysis results of the fuel tank crack is the negative pressure due to engine purge and the decreased canister venting performance because of the dust, so canister venting performance have be improved but the fuel tank crack have not been solved.
2017-03-28
Technical Paper
2017-01-0449
Yinzhi He, Bin Wang, Zhe Shen, Zhigang Yang, Gunnar Heilmann, Tao Zhang, Guoxu Dong
Beamforming technique is today widely used in aeroacoustic wind tunnel to identify wind noise sources generated by interaction between incoming flow and test object. In this study, a planar spiral microphone array with 120 channels was set out-of –flow of 1:1 aeroacoustic wind tunnel of Shanghai Automotive Wind Tunnel Center (SAWTC) to test exterior noise sources of a production car. Simultaneously, 2 reference microphones were set in vehicle interior to record potential sound source signals synchronously and a spherical array with 48 channels inside the vehicle to identify interior noise sources. With different correlation methods and some advanced algorithms, i.e. using CSM and Clean-Sc, the ranking of contributions of vehicle exterior wind noise sources to interested interior noise locations was accomplished. Hereby, Correlation analysis results of interior and exterior noise sources using virtual and real reference microphones are compared and discussed.
2017-03-28
Technical Paper
2017-01-0801
Keith Vertin, Brent Schuchmann, William Studzinski, Richard S. Davis, Thomas G. Leone, James E. Anderson, Asim Iqbal
Automakers are designing smaller displacement engines with higher power densities, to improve vehicle fuel economy while continuing to meet customer expectations for power and drivability. The specific power produced by the spark-ignited engine is constrained by knock and fuel octane ratings. Knock can lead to engine component damage and excessive exhaust gas temperatures that may cause thermal deactivation of catalytic convertors. Whereas the lowest octane rating is 87 AKI (anti-knock index) for regular gasoline at most service stations throughout the country, 85 AKI fuel is widely available at higher altitudes especially in the mountain west states. The objective of this study was to explore the effect of gasoline octane rating on the net power produced by modern light duty vehicles at high altitude conditions (1660m elevation). A chassis dynamometer test procedure was developed to measure absorbed wheel power at momentary and stabilized full power operation.
2017-03-28
Technical Paper
2017-01-1388
S. M. Akbar Berry, Michael Kolich, Johnathan Line, Waguih ElMaraghy PhD
Thermal comfort in automotive seating has been studied and in discussion for a long time. The available research, because it is focused on the components, has not produced a model that provides insight into the human-seat system interaction. This work, which represents the beginning of an extensive research program, aims to establish the foundation for such a model. This paper will discuss the key physiological, psychological, and biomechanical factors related to perceptions of thermal comfort in automotive seats. The methodology to establish perceived thermal comfort requirements is also presented and discussed.
2017-03-28
Technical Paper
2017-01-0131
Chiranth Srinivasan, Chonglin Zhang, Haiyang Gao, De Ming Wang, Jody Slike
In an automotive cooling circuit, the wax melting process determines the net and time history of the energy transfer between the engine and its environment. A numerical process that gives insight into the mixing process outside the wax chamber, the wax melting process, and the effect on the poppet valve displacement will be advantageous to both the engine and automotive system design. A fully three dimensional, transient, system level simulation of an inlet controlled automotive cooling circuit is undertaken in this paper. A proprietary CFD algorithm, PumpLinx®, is used to solve this complex problem. A two-phase model is developed in PumpLinx® to simulate the wax melting process. The hysteresis effect of the wax melting process is also considered in the simulation. The coolant circulated using a centrifugal pump, which operates via a constant ratio with respect to the engine speed, is modeled as part of the computational domain.
2017-03-28
Technical Paper
2017-01-0145
Edward Palmer, Wilko Jansen
The primary function of the brake system is to convert the kinetic energy of the vehicle to heat which is then dissipated to the environment. The performance characteristics of many of the components within the brake system are temperature dependant; with numerous issues associated with excessive temperatures such as vaporisation of the brake fluid, degradation of the friction coefficient at the disc to pad interface, thermo-mechanical deformation of the brake rotor, excessive wear and numerous NVH problems. Therefore it is clear that in order to avoid the customer encountering these failure modes the brakes must be specified with sufficient thermal inertia and cooling for the intended vehicle and drive cycle. This paper presents a high fidelity CAE technique for predicting the temperature of the front brake and the surrounding suspension components whilst installed on vehicle.
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