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Technical Paper
2014-09-30
Oscar Flores-Centeno, Manuel Fabela-Gallegos, David Vazquez-Vega, Carlos Blake-Cervantes, Ricardo Hernandez-Jimenez
The vehicle’s dynamic behavior is influenced mainly by the interaction of four factors: driver, vehicle, road an environment. Under given circumstances, perturbation of these factors can cause degradation of vehicles´ performance; as a result, an accident will take place affecting the vehicle itself, road infrastructure and injury or even death of passenger(s). In order to increase road safety is essential to fully understand the interaction of those factors on vehicle’s dynamic behavior, especially heavy vehicles due to its greater mass, dimensions and potential damage that can cause. This paper presents the effect of road condition on the dynamic behavior of a 3-axle straight-truck based on numerical simulations. Validated commercial software was used. Three different road conditions were studied, namely potholes, longitudinal level differences between adjacent lanes due to repairing process, and different surface friction coefficients also due to road repairing process. For numerical simulations, three standardized maneuvers were taken into account, namely, single and double lane change and panic braking.
Technical Paper
2014-09-30
Sijing Guo, Zhenfu Chen, Xuexun Guo, Quan Zhou, Jie Zhang
Hydraulic electromagnetic shock absorber (HESA) consists of hydraulic cylinder and check valves etc., by which the high-pressure oil produced by shock absorber reciprocation could be exported to drive the hydraulic motor, so as to drive the generator, and eventually recover the mechanical vibration energy otherwise dissipated by the traditional shock absorber as heat energy. Hydraulic Interconnected Suspension(HIS) can improve the vehicle roll and pitch stablity performance by interconnecting the chambers of the shock absorbers on the vehicle. To integrate both the advantages of HESA and HIS, a new type of suspension system is proposed in this paper, namely Hydraulic Interconnected Suspension system based on Hydraulic Electromagnetic Shock Absorber (HESA-HIS). HESA-HIS has three operating modes: energy-recovery priority mode, driving stability performance priority mode and energy-recovery and driving stability performance balance mode. The working principle of HESA-HIS in the three operating modes is introduced, and the mathematic theory model is deduced with relative automobile theory knowledge.
Technical Paper
2014-09-30
Mehmet Bakir, Murat Siktas, Serter Atamer
In today's world, there are a prominent number of weight & cost reduction projects within the vehicle engineering development activities. Regarding this phenomenon, a complete optimization study is applied to a 4-leaf pendulum leaf spring used in heavy duty trucks by reducing the number of leaves down to 3 together with weight and cost reductions. Leaf spring itself plays a crucial role in a heavy duty truck structure. Because of this purpose, the new designs should withstand all forces like the current design assuring same strength and fatigue characteristics. In other words, it should be lower in price and weight but at the same time strong enough to maintain its durability throughout its life time. This fact brings great responsibility to the development process of the new optimized leaf springs. Hence, a complete optimization process is applied from scratch till the very end which is illustrated in this paper. At the first step of the project, the stiffness of the leaf spring is calculated with an in-house software based on mathematical calculations using the thickness profile of the leaves.
Technical Paper
2014-09-30
Zhigang Wei, Limin Luo, Shengbin Lin
This paper reviews the correlation concepts and tools available, with the emphasis on their historical origins, mathematical properties and applications. Two of the most commonly used statistical correlation indicators, i.e., modal assurance criterion (MAC ) for structural deformation pattern identification/correlation and the coefficient of determination (R^2 ) for data correlation are investigated. The mathematical structure of R^2 is critically examined, and the physical meanings and their implications are discussed. Based on the insights gained from these analyses, a data scatter measure and a dependency measure are proposed. The applications of the measures for both linear and nonlinear data are also discussed. Finally, several worked examples in vehicle dynamics analysis and statistical data analyses are provided to demonstrate the effectiveness of these concepts.
Technical Paper
2014-09-30
Marc Auger, Larry Plourde, Melissa Trumbore, Terry Manuel
Design of body structures for commercial vehicles differs significantly from automotive due to government, design, usage requirements. Specifically the design of heavy truck doors differ as they are not required to meet side impact requirements due to their height off the ground as compared to automobiles. However, heavy truck doors are subjected to higher loads, longer life and less damage from events. Past aluminum designs relied either on bent extrusions around the periphery of the door or multiple steel and/or aluminum reinforcements joined to the inner in order to provide the necessary structure. Doors using aluminum extrusions for the peripheries were limited to two dimensional bending for the extrusions resulting in a planar door with limited styling features an opportunity for aerodynamic improvements. Doors with stamped reinforcements and door mounted mirrors require joining the inner and outer structure at the lower mirror mount forcing the use of a division bar to split the glass that impedes vision and drives cost for the extra parts.
Technical Paper
2014-09-30
Xinyu Ge, Jonathan Jackson
Cost reduction in automotive industry becomes a widely-adopted operational strategy not only for Original Equipment Manufacturers (OEMs) that take cost leader generic corporation strategy, but also for many OMEs that take differentiation generic corporation strategy. Since differentiation generic strategy requires an organization to provide a product or service above the industry average level, a premium is typically included in the tag price for those products or services. Cost reduction measures could increase risks for the organizations that pursue differentiation strategy. Although manufacturers in automotive industry dramatically improved production efficiency in past ten years, they are still facing up with the pressure of cost control. The big challenge in the cost control for automakers and suppliers is increasing prices of raw materials, energy and labor costs. These costs construct constrains for the traditional economic expansion model. Lean manufacturing and other traditional Six Sigma processes have been widely utilized to reduce waste and improve efficiency further in the automotive industry.
Technical Paper
2014-09-30
Venkatesan C, DeepaLakshmi R
The automotive industry is constantly looking for new alternate material and cost is one of the major driving factors for selecting the right material. ABT is a safety critical part and care to be taken while selecting the appropriate material. Polyamide 12(PA12) is the commonly available material which is currently used for ABT applications. Availability and cost factor is always a major concern for commercial vehicle industries. This paper presents the development of an alternative material which has superior heat resistance. Thermoplastic copolyester (TEEE) materials were tried in place Polyamide 12 for many good reasons. The newly developed material has better elastic memory and improved resistance to battery acid, paints and solvents. It doesn’t require plasticizer for extrusion process because of which it has got excellent long term flexibility and superior kink resistance over a period of time. Also it has got better heat ageing properties and higher burst pressure at elevated temperature.
Technical Paper
2014-09-16
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]. Requirements specifying the necessity of CP-related activities are specified in the national standards concerning the organization of quality management system (QMS) in the aviation industry as well as programs of safety, reliability and maintainability activities.
Technical Paper
2014-09-16
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). This article investigates the aforementioned stress mechanisms and provides analysis techniques and metrics to quantify the impact of transient operating conditions onto system and component reliability and life.
Technical Paper
2014-04-01
James G. McLeish, Russell Haeberle
Quality, Reliability, Durability (QRD) and Safety of vehicular Electrical/Electronics (E/E) systems traditionally have resulted from arduous rounds of Design-Built-Test-Fix (DBTF) Reliability and Durability Growth Testing. Such tests have historically required 12-16 or more weeks of Accelerated Life Testing (ALT), for each round of validation in a new product development program. Challenges have arisen from: The increasing number of E/E modules in today's vehicle places a high burden on supplier's test labs and budgets. The large size and mass of electric vehicle power modules results in a lower test acceleration factors which can extend each round of ALT to 5-6 months. Durability failures tend to occur late in life testing, resulting in the need to: perform a root cause investigation, fix the problem, build new prototype parts and then repeat the test to verify problem resolutions, which severely stress program budgets and schedules. To resolve these challenges, automakers and E/E suppliers are moving to Physics of Failure (PoF) based durability simulations and reliability assessment solutions performed in a Computer Aided Engineering (CAE) Environment.
Technical Paper
2014-04-01
David E. Verbitsky
Failure analysis (FA) management is insufficiently described by current standards and literature. Previously proposed three-step systemic FA methodology provides effective and efficient alternative to sporadic FA. Organization, methods and results of the first step of the systemic FA, failure mode analysis (FMA), during product/project life cycle, is described. FMA promptly address ∼80% of all problems and justify/supports further actions using conventional ready techniques and resources. Original subject matter tools (three FMA levels, joint FMA-FMECA-F5 technique, and P5 failure classification) substantiate, facilitate and illustrate FMA. Multiple examples demonstrate FMA strengths and limitations with uniquely broad range of products and applications. Particular attention is paid to rare combination of high quality, reliability and profitability.
Technical Paper
2014-04-01
Melanie Zielenski, Peter Downes, Darren Jelbert
Abstract Heavy duty diesel engine development has always faced high customer durability requirements, short development timelines and increasingly stringent emissions legislations. However, more frequently heavy duty engines are being used in multiple vehicle platforms across the globe with increasingly stringent quality demands in emerging markets. In order to meet engine life requirements, Delphi Diesel Systems has adapted accepted validation procedures to evaluate their system performance for the global market. In addition to durability and structural testing Delphi Diesel Systems has introduced specialized tests to validate their product at extremes of environmental conditions and fuel properties and has increased OEM collaboration. This paper details some of the adjustments made to the validation test suite to meet the specific challenges of the Heavy Duty market.
Technical Paper
2014-04-01
Alaa El-Sharkawy, Asif Salahuddin, Brian Komarisky
In this paper a design methodology for automotive heat exchangers has been applied which brings robustness into the design process and helps to optimize the design goals: as to maintain an optimal coolant temperature and to limit the vehicle underhood air temperature within a tolerable limit. The most influential design factors for the heat exchangers which affect the goals have been identified with that process. The paper summarizes the optimization steps necessary to meet the optimal functional goals for the vehicle as mentioned above. Taguchi's [1] Design for Six Sigma (DFSS) methods have been employed to conduct this analysis in a robust way.
Technical Paper
2014-04-01
Andre Kleyner
This paper discusses the effect of the field stress variance on the value of demonstrated reliability in the automotive testing. In many cases the acceleration factor for a reliability demonstration test is calculated based on a high percentile automotive stress level, typically corresponding to severe user or environmental conditions. In those cases the actual field (‘true’) reliability for the population will be higher than that demonstrated by a validation test. This paper presents an analytical approach to estimating ‘true’ field reliability based on the acceleration model and stress variable distribution over the vehicle population. The method is illustrated by an example of automotive electronics reliability demonstration testing.
Technical Paper
2014-04-01
Valerie Earlene Bumbaca
Abstract Virtually every major automaker has announced intentions of producing an electric vehicle (EV). Hyundai Motor Group has also announced plans to sell an electric vehicle in the next several years. There is strong and increasing support for electric vehicles in the USA due to an interest in protecting the environment, limiting dependence on oil, and reducing the associated cost of petroleum-based transportation. From a durability perspective, battery performance and longevity are significant concerns. In order to better prepare for upcoming electric vehicles, Hyundai-Kia America Technical Center, Inc (HATCI) Vehicle Evaluation group is developing an EV durability test and battery lifecycle laboratory test based on real world EV customer usage. Since there is limited availability of real world customer information for electric vehicles, a program has been started to collect EV customer usage data. This will be correlated with test inputs for both road and lab testing. An outside vendor has been contracted to collect data on customer usage from existing Nissan Leaf and Chevrolet Volt customers.
Technical Paper
2014-04-01
Venkatesh Agaram
Abstract Cars and trucks today are getting fitted with a large number of sensors in an effort to improve safety, comfort, fuel economy and emissions. The revenue from the automotive sensors market, driven by intense global competition and regulation, is expected to double over the next decade, while the size of the automotive sensors market, over the same period, is expected to triple The field of sensor-fusion is highly multi-disciplinary, making use of technics from artificial intelligence, pattern recognition, digital signal processing, control theory, and statistical estimation. Sensor-fusion strategies based on probability theory, evidence theory, fuzzy theory, and possibility theory are being explored in different industries, e.g., defense, robotics, automotive, etc. The majority of sensor-fusion operators are based on optimistic assumptions about reliability of the information generated by the sensors. However, many or all of sensors in a fused sensor system may exhibit substantially different reliability levels over the life of a vehicle, and it is necessary to account for this variation/degradation to avoid any decrease in performance of the fusion results.
Technical Paper
2014-04-01
Takamasa Shimodaira
Abstract The aim discussed in this paper is to show a technique to predict loads input to the wheels, essential to determining input conditions for evaluation of suspension durability, by means of full vehicle simulations using multi body analysis software Adams/Car. In this process, model environments were built to enable reproduction of driving modes, and a method of reproducing the set-up conditions of a durability test vehicle was developed. As the result of verification of the accuracy of the simulations in the target driving modes, good correlation for waveforms can be confirmed. And also confirm a good correlation in relation to changes of input load due to changes in suspension specifications.
Technical Paper
2014-04-01
Hong Su
Durability of a product is related to three major factors, the load, structure and material. The durability performance of an automotive product is, therefore, not only depended on the structure configuration, but also on the road load dynamic characteristics (profiles and frequency spectrum), and the material fatigue properties as well. Due to the dynamic nature of vehicle loads, one of the major technical challenges, to the durability design optimization of automotive products, is how to define a set of representative road loads, for fidelity and efficiency, based on the measured proving ground durability data of huge size. This paper presents a procedure of processing the proving ground road loads, for vehicle durability design and optimization of automotive products, based on the statistical characteristics evaluation and fatigue damage equivalency techniques. A practical method for constructing a set of representative road load data, with much shorter time duration, is introduced, which satisfy all statistical property fidelity requirements with respect to the original measured load data.
Technical Paper
2014-04-01
Weiguo Zhang, Rakesh Khurana, Mark Likich, Mac Lynch
Taguchi method is a technology to prevent quality problems at early stages of product development and product design. Parameter design method is an important part in Taguchi method which selects the best control factor level combination for the optimization of the robustness of product function against noise factors. The air induction system (AIS) provides clean air to the engine for combustion. The noise radiated from the inlet of the AIS can be of significant importance in reducing vehicle interior noise and tuning the interior sound quality. The porous duct has been introduced into the AIS to reduce the snorkel noise. It helps with both the system layout and isolation by reducing transmitted vibration. A CAE simulation procedure has been developed and validated to predict the snorkel noise of the porous ducted AIS. In this paper, Taguchi's parameter design method was utilized to optimize a porous duct design in an AIS to achieve the best snorkel noise performance. The virtual experiments based on an orthogonal array in the parameter design method were conducted by the developed simulation procedure and the optimized design was recommended.
Technical Paper
2014-04-01
Christian Scheiblegger, Nantu Roy, Orlando Silva Parez, Andrew Hillis, Peter Pfeffer, Jos Darling
Abstract Cab mounts and suspension bushings are crucial for ride and handling characteristics and must be durable under highly variable loading. Such elastomeric bushings exhibit non-linear behavior, depending on excitation frequency, amplitude and the level of preload. To calculate realistic loads for durability analysis of cars and trucks multi-body simulation (MBS) software is used, but standard bushing models for MBS neglect the amplitude dependent characteristics of elastomers and therefore lead to a trade-off in simulation accuracy. On the other hand, some non-linear model approaches lack an easy to use parameter identification process or need too much input data from experiments. Others exhibit severe drawbacks in computing time, accuracy or even numerical stability under realistic transient or superimposed sinusoidal excitation. To improve bushing modeling of cab/box mounts for heavy duty/light duty trucks, a practical approach to model non-linear bushing dynamic characteristics has been tested and validated against standard bushing models.
Technical Paper
2014-04-01
Mohamed Sithik, Rama Vallurupalli, Barry (Baizhong) Lin, Subash Sudalaimuthu
Abstract In recent trend, there is a huge demand for lightweight chassis frame, which improves fuel efficiency and reduces cost of the vehicle. Stiffness based optimization process is simple and straightforward while durability (life) based optimizations are relatively complex, time consuming due to a two-step (Stress then life) virtual engineering process and complicated loading history. However, durability performances are critical in chassis design, so a process of optimization with simplified approach has been developed. This study talks about the process of chassis frame weight optimization without affecting current durability performance where complex durability load cases are converted to equivalent static loadcases and life targets are cascaded down to simple stress target. Sheet metal gauges and lightening holes are the parameters for optimization studies. The optimization design space is constrained to chassis unique parts. The optimized design is verified for detailed load case and life target.
Technical Paper
2014-04-01
Ram Kiran Tholeti, Shyamsundar Kumbhar, Nainish Kumar B, R Govindarajan
Abstract Scooter segment growth is tremendously increasing in India. The increased competition challenges automotive manufacturers to deliver the high quality and high reliable product to the market. Higher reliability involves increased durability testing which involves time and cost. Stress testing a part of durability is initially conducted on prototype vehicles for structural design validation and then later on production units to ensure its structural integrity. The obtained data from the tests can be used for future structural design improvements. Scooters with small tires, suspension limitations transfers more loads to structure, challenges engineers to design robust structure without compromising on weight much. It is necessary to look at Real World Usage Pattern (RWUP) and to create a stress life cycle block for simulation of accelerated testing, thereby optimizing the testing time and the development costs. The aim of this paper is to provide a procedure for deriving an accelerated stress test cycle for evaluation of chassis based on Road Load Data Acquisition (RLDA).
Technical Paper
2014-04-01
Zhigang Wei, Limin Luo, Shengbin Lin, Dmitri Konson
Abstract A modern definition of quality control and improvement is the reduction of variability in processes and products. The reduced variability can be directly translated into lower costs, better functions and fewer repairs. However, the final quality of processes and products is sometimes derived from other measured variables through some implicit or explicit functional relationships. Sometimes, a tiny uncertainty in a variable can produce a huge uncertainty in a derived quantity. Therefore, the propagation of uncertainty needs to be understood and the individual variables need to be well controlled. More importantly, the critical factors that affect quality the most should be identified and thoroughly investigated. Design of experiments and statistical control plays central roles in finding root cause of failure, reduction of variability and quality improvement. In this paper, the theories on quality control and improvement are reviewed first with the emphasis on statistical data analysis and uncertainty propagation.
Technical Paper
2013-09-17
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. In this paper, we propose a statistical approach based on the extreme value analysis to improve the identification module of the IDI.
Technical Paper
2013-04-08
Marcella Turano, Fulvio Civera, Guilherme Figueiredo, Marco Margaria, Andre Smith Pereira
Fatigue tests on exhaust system usually require long time to be performed on the proving ground. Road simulation bench test reduces the time needed to execute the entire fatigue test on the proving ground and does not involve the operator presence for long time as proving ground test requires. In order to put on evidence the potentiality of performing the fatigue test with the RSB in substitution of the fatigue test on proving ground, a correlation between virtual analysis, the proving ground test and RSB test are illustrated. A specific component of the exhaust system is studied and specifically the bracket connecting the flexible pipe to the vehicle under body. During the proving ground test several failures occurred on the bracket connecting the exhaust system and the gear box. A virtual FE calculation and a fatigue test on the Road Simulation Bench were required to investigate the failure. The results of both the analyses showed a critical condition for the bracket During the Road Simulation Bench fatigue test the failure of the bracket is registered shortly before the one on proving ground; this shows that bench conditions for the component are conservatives compared with real ones.
Technical Paper
2013-04-08
Lev Klyatis
There are no standards that directly consider practical reliability testing technology (methods and equipment). This void needs to be filled. The SAE G-11 division has approved the development of six new standards to fill this void. This paper discusses these six standards: 1) Reliability Test-Glossary; 2) Reliability Testing-Strategy; 3) Reliability Testing-Procedures; 4) Reliability Testing-Equipment; 5) Reliability Testing-Statistical Criteria for Comparison of Reliability Testing Results and Field Results; 6) Reliability Testing-Collection, Calculation, and Statistical Analysis of Reliability Testing Data, Development Recommendations for Improvement of Test Subject Reliability, Durability, and Maintainability. These standards are planned as a basis for obtaining the information needed to accurately predict usage, reliability, durability, quality, supportability and maintainability throughout the life-cycle, as well as life-cycle costs in real-world conditions, and to reduce the possibility of conflicts, duplications, and incorrect interpretations either expressed or implied elsewhere in the literature.
Technical Paper
2013-04-08
Lev Gorelik
A powerful methodology of reliability testing is described. This technique is based on the application of dimensional analysis. The whole process of determination of reliability consists of the choosing the relevant physical quantities, calculation the corresponding complete set of dimensionless variables, obtaining the Model Law, and the determination of the limited condition of reliability for the product (prototype). The application of the presented methodology is demonstrated on the example of the determination of reliability of revolving disc.
Technical Paper
2013-04-08
Lev Klyatis
This paper will discuss the first two standards in the six-part series of SAE International reliability testing documents that are being developed by the SAE G11 Reliability Committee. These two documents attempt to standardize the glossary and strategy associated with reliability testing technology. A new Glossary standard has been drafted that defines the most commonly used words and terms associated with reliability (accelerated reliability/durability) testing. It is intended to serve as a basis for reliability testing definitions and to reduce the possibility of conflicts, duplications, and incorrect interpretations either expressed or implied elsewhere in the technical literature. Terms and definitions included in this standard are important in the acquisition of weapon systems (where there is a need for precise and unambiguous technical definitions), and are expressed clearly (and without mathematical symbols whenever possible). The Strategy document and the remaining other documents in the reliability testing series are to become subdocuments in a revision to JA1009 (Reliability Testing).
Technical Paper
2013-04-08
Rasmus Adler
A safety concept describes a plan for implementing safety. A bad safety concept compromises the achievement of safety or leads to unnecessarily high costs for implementing and proving safety. However, safety standards and research approaches do not provide any means for developing a good safety concept or for assessing the quality of a safety concept. Consequently, real-world safety concepts often lack information or have low quality. To overcome this practical problem, we systematically derive which fundamental information should be contained in a safety concept and introduce quality attributes for a safety concept. We also evaluate state-of-the-art approaches for developing a safety concept.
Technical Paper
2013-04-08
Joseph G. D'Ambrosio, Rami Debouk
ASIL decomposition is a method described in the ISO 26262 standard for the assignment of ASILs to redundant requirements. Although ASIL decomposition appears to have similar intent to the hardware fault tolerance concept of IEC 61508-2, ASIL decomposition is not intended to reduce ASIL assignments to hardware elements for random hardware failures, but instead focuses on functions and requirements in the context of systematic failures. Based on our participation in the development of the standard, the method has been applied in different ways in practice, not all of which are fully consistent with the intent of the standard. Two potential reasons that may result in the use of “modified” ASIL algebra include the need of OEMs to partition a system and specify subsystem requirements to suppliers and the need for designers to construct systems bottom up. Constructing systems bottom up has the goal of achieving a target system level ASIL from component elements that have some notion of ASIL already associated with them.
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