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Viewing 1 to 30 of 7932
2010-04-12
Technical Paper
2010-01-0419
Yan Fu, Zhenfei Zhan, Ren-Jye Yang
This paper presents an enhanced Bayesian based model validation method together with probabilistic principal component analysis (PPCA). The PPCA is employed to address multivariate correlation and to reduce the dimensionality of the multivariate functional responses. The Bayesian hypothesis testing is used to quantitatively assess the quality of a multivariate dynamic system. Unlike the previous approach, the differences between test and CAE results are used for dimension reduction though PPCA and then to assess the model validity. In addition, physics-based thresholds are defined and transformed to the PPCA space for Bayesian hypothesis testing. This new approach resolves some critical drawbacks of the previous method and provides desirable properties of a validation method, e.g., symmetry. A dynamic system with multiple functional responses is used to demonstrate this new approach.
2010-04-12
Technical Paper
2010-01-0421
Greg Browne, Nicholas Krouglicof, Geoff Rideout
Mathematical modeling is widely used throughout any scientific industry when trying to predict the behavior of dynamic systems. Oftentimes it is desirable that these models be simple and efficient, while still delivering accurate data. This paper builds and examines an energy-based (bond graph) model of an automotive fuel delivery system and suggests which elements are required to produce a Proper Model. The Model Order Reduction Algorithm (MORA) provides a mechanism to quantitatively rank each element in the model and determine its contribution to the system dynamics. Utilizing this approach, a model is developed that retains 98% of the complete system energy from 12 of the most active of 25 elements. This model requires 46.6% less simulation time while continuing to provide an adequate prediction of the system response.
2010-04-12
Technical Paper
2010-01-0407
Jafar Albinmousa, Adrian Pascu, Hamid Jahed, M.F. Horstemeyer, Alan Luo, D. Chen, Steve Lambert, J. Jordon, S. Begum, Xuming Su, Q.Q. Duan, Richard Osborne, Z. Zhang, Lin Zhang, T. Luo, Yuansheng Yang
Magnesium alloys are the lightest structural metal and recently attention has been focused on using them for structural automotive components. Fatigue and durability studies are essential in the design of these load-bearing components. In 2006, a large multinational research effort, Magnesium Front End Research & Development (MFERD), was launched involving researchers from Canada, China and the US. The MFERD project is intended to investigate the applicability of Mg alloys as lightweight materials for automotive body structures. The participating institutions in fatigue and durability studies were the University of Waterloo and Ryerson University from Canada, Institute of Metal Research (IMR) from China, and Mississippi State University, Westmorland, General Motors Corporation, Ford Motor Company and Chrysler Group LLC from the United States.
2010-04-12
Technical Paper
2010-01-0410
Alan A. Luo, Joy Forsmark, Xichen Sun, Scott Shook
Magnesium alloy extrusions offer potentially more mass saving compared to magnesium castings. One of the tasks in the United States Automotive Materials Partnership (USAMP) ?Magnesium Front End Research and Development? (MFERD) project is to evaluate magnesium extrusion alloys AM30, AZ31 and AZ61 for automotive body applications. Solid and hollow sections were made by lowcost direct extrusion process. Mechanical properties in tension and compression were tested in extrusion, transverse and 45 degree directions. The tensile properties of the extrusion alloys in the extrusion direction are generally higher than those of conventional die cast alloys. However, significant tension-compression asymmetry and plastic anisotropy need to be understood and captured in the component design.
2010-04-12
Technical Paper
2010-01-0397
Victor Calagias
Companies are often faced with periods of fluctuating product demand that can make it difficult to maximize the usage of their capacity and resources. This makes it challenging to realize potential profit and can even have detrimental effects on the bottom line. Developing flexibility strategies to react to fluctuations in demand allows a manufacturer to dynamically adjust capacity and resources to keep costs under control. This project was pursued at a diesel engine manufacturer for two older product lines experiencing consistently declining volumes. The volumes were declining due to this company releasing newer products in the market, and the current economic downturn. There was also an expectation to eventually phase out these two engines after approximately five years. A project team was formed to address these challenges starting with defining the project scope, setting up the team and a cross-functional project structure, and developing work packages with a master timeline.
2010-04-12
Technical Paper
2010-01-0398
Ravi Anand
OEE or Overall Equipment Effectiveness is the metric that ties machine availability, performance and part quality together. OEE is calculated using the formula, OEE = Machine Availability x Machine Performance x Quality of parts produced by the machine. The ideal value for plant OEE is 100% which means all machines have zero downtime, full availability and are not making any non conforming parts. Studies show that average OEE in the manufacturing industry is about 60% whereas world class OEE is 85%. Most manufacturers have room for improving their OEE. In order to improve OEE, this metric needs to be monitored for all machines or equipment in the plant. And there is nothing simpler than a dashboard to monitor OEE for plant equipment.
2010-04-12
Technical Paper
2010-01-0399
Sachin Jain
Organizations spend millions of dollars on analytical and simulation inventory models to optimize inventory across the supply chain. However, these methods are expensive, difficult to implement and fail to capture all the requirements for defining inventory levels across supply chain. The effect of planned and unplanned equipment downtime, a key factor, is not properly utilized in these models. Many methods use standard statistical distributions, which do not fully capture downtime characteristics of an operation. This may lead to inaccurate computation of inventory sizes. The purpose of this paper is to communicate a new analytical approach of defining inventory levels which is robust enough to consider non-normal distributions associated with equipment downtime. The proposed method is easy to use, less time consuming and can be adapted quickly with changing operational dynamics. The method is based on utilizing equipment performance data to scientifically compute inventory levels.
2010-04-12
Journal Article
2010-01-0400
Mohamed El-Sayed
Implementing the lean principles and tools in manufacturing has been successful in many companies. This success has led to different implementations, of these principles, in other organizational activities such as design and management. While these implementations can produce some improvements, the segmentation of the product development processes in most company limits the potential for achieving the desired goals and in some cases the success of the implementation process itself. In other words, full success of lean principles implementation cannot be achieved when applied to isolated segments of the product development process. This paper addresses lean design, in the context of a fully integrated product realization process. The paper discusses the integrated nature of any product realization process and its flow from concept to production.
2010-04-12
Technical Paper
2010-01-0401
Ashok Patidar
In a very competitive environment, product development in automobile industry needs to be fast paced with best in quality to stay ahead in the race. Therefore a clear understanding of customer requirements is essential in successful design and development of systems. Failure in any system development step can result in costly design and tooling changes, schedule delays and ultimately, customer dissatisfaction. A team was formed to design and develop an automotive system by applying Design for Six Sigma Green Belt methods and tools. The hypothesis of this study was that a substantial opportunity exists to increase project efficiency while providing what customer wants, by following a standardized statistical work practice for managing requirements throughout the life of product development using the methodology of Design for Six Sigma DMADV (Define, Measure, Analyze, Design and Verify). In this paper an automotive HVAC system is designed following DFSS methodology.
2011-04-12
Technical Paper
2011-01-0426
Mark E. DeBruin, S. E. Jordan
Significant research has been conducted with the goal of obtaining thin walled ductile iron for use in lighter weight designs. A review is made of the past efforts to achieve thin walled ductile iron. Most past efforts resorted to costly processes or non-standard production practices. Lost Foam Casting (LFC) is an alternate foundry process which used in conjunction with standard melt shop practices results in a massive carbide free structure when used with thin section size. Chemistry, hardness tests, microstructures, and design improvements of a case study are reviewed.
2011-04-12
Technical Paper
2011-01-0466
Mohammad R. Movahhedy, Saeed khodaygan
The process capability indices are widely used to measure the capability of the process to manufacture objects within the required tolerance. Fit quality is mainly dominated by the distribution of fit dimensions, i.e., a gap dimension. As the fit dimensions are very difficult to be measured in mass production, they are not to be considered as a direct inspection objective. The quality inspection and evaluation relative to fit quality are focused on whether the processes of assembly requirements are conformed with their specification limits respectively. Fit quality specification can be indicated by the process capability indices of mating parts. In this paper, the statistical-based process capability analysis method is presented to estimate ability of manufacturing process for considering of assembly requirements and fit quality in a mechanical assembly with asymmetric tolerances.
2011-04-12
Journal Article
2011-01-0470
Pai-Chen Lin, Ru-Yi He, Zheng-Ming Su, Zhi-Long Lin
Failure modes of spot friction welds in cross-tension specimens of aluminum 6061-T6 sheets are first investigated based on experimental observations. Optical and scanning electron micrographs of the welds before and after failure under quasi-static and cyclic loading conditions are examined. Experimental results show that the failure modes of the welds under quasi-static and cyclic loading conditions are quite different. Under quasi-static loading conditions, the failure mainly starts from the necking of the upper sheet outside the weld. Under low-cycle loading conditions, the dominant fatigue cracks are the kinked cracks growing into the upper sheet from the crack tips; hence, the upper nugget pullout failure mode can be seen. Under high-cycle loading conditions, the dominant fatigue cracks are kinked cracks growing into the lower sheet from the crack tips; subsequently, the lower nugget pullout failure mode can be seen.
2011-04-12
Technical Paper
2011-01-0471
Jiwoong Ha, Yujong Kim, Jiho Lim
This paper proposes an alternative methodology to construct a dynamic failure model of spot welds under combined axial and shear loading conditions for auto-body crash analyses performing cross-tension tests and lap-shear tests which are substitution of pure-shear tests. To construct a failure model of a spot weld proposed by Song and Huh, failure tests of spot welds with an imposed angle to the weldment have to be carried out at an interval of 15° from 0° to 90°. In the general case, it was suggested that the β value of 1.45 from the results of the failure load of cross-tension tests and pure-shear tests can be used for constructing their failure model. However, the scheme is not practical because of difficulties in making pure-shear specimens with the same welding conditions of two-sheet spot weld because the pure-shear specimen is generally prepared with three-sheet spot weld.
2011-04-12
Technical Paper
2011-01-0472
Oliver Scholz, Rolf Behrendt, Thomas Wenzel, Thomas Stocker, Jörg Müller
The inspection of steel welds is a requirement in many safety critical applications, with X-rays offering an excellent visual aid in quality monitoring of such parts. In order to penetrate the steel and the weld, high energy X-rays are usually required though, depending on the material's thickness and the length of material the X-ray beams must traverse. The high beam energies can seriously degrade the X-ray detectors' life expectancy and image quality, so in order to ensure consistent image quality traditional X-ray film has been used, in spite of its drawbacks regarding the ecological impact of the chemical process and the significant efforts involved if archives of the welds must be maintained. This paper presents an alternative solution to the traditional photochemical archival approach using a custom X-ray detector developed specifically for the inspection of welded seams.
2010-10-10
Technical Paper
2010-01-1673
Akira Tojo, Shinichi Arai, Kenji Kakinuma
Being environmentally conscious in reducing CO2 output, is driving industries to be more efficient in using resources. Industries are also finding ways to reduce energy consumption for all aspects of manufacturing. The brake lining manufacturing process relies on electric power during the thermoset cure and post-cure of Phenol Novolac resin. Unreacted resin will complete its cure process during the ‘post-cure’ phase. The electric power consumed during the molding and post-cure process is significant compared to the total power consumed for the entire lining manufacturing process. By using Novolac Benzo-oxazine resin and utilizing high temperature short cycle molding, we could reduce power consumption. The finished Phenol Novolac brake lining will have the same performance as the phenol brake lining. A substantial reduction in electric power consumption is achieved with the new process.
2010-04-12
Technical Paper
2010-01-0532
Hans-Joerg Rembor, Thomas Rahn
In this paper, a new diesel particle filter material made from silicon carbide sintered in a liquid phase is presented. The sintering process allows for controlling of certain parameters that influence the extrusion process, the material properties and hence the filtering characteristics. Furthermore, using triangular channel geometry to build up a wall flow filter makes it possible to have a newly segmented geometry that leads to hexagonal shaped filter cartridges. A variety of on the market available wall flow filter materials are compared with data about material porosity, particle size distribution, strength, specific filtration surface as well other parameters influencing the filtration efficiency. The material characteristics gathered are analyzed and evaluated.
2010-04-12
Journal Article
2010-01-0645
Ramon Kuczera, Zissimos Mourelatos, Efstratios Nikolaidis
A simulation-based, system reliability-based design optimization (RBDO) method is presented that can handle problems with multiple failure regions and correlated random variables. Copulas are used to represent the correlation. The method uses a Probabilistic Re-Analysis (PRRA) approach in conjunction with a trust-region optimization approach and local metamodels covering each trust region. PRRA calculates very efficiently the system reliability of a design by performing a single Monte Carlo (MC) simulation per trust region. Although PRRA is based on MC simulation, it calculates “smooth” sensitivity derivatives, allowing therefore, the use of a gradient-based optimizer. The PRRA method is based on importance sampling. It provides accurate results, if the support of the sampling PDF contains the support of the joint PDF of the input random variables. The sequential, trust-region optimization approach satisfies this requirement.
2010-04-12
Technical Paper
2010-01-0646
Marco Junglas, Ruediger Eick, Amir Kazeminia, Dirk Soeffker
During development process phases, mechatronic systems needs to be quantified to decide in early design phase which topology or hardware satisfy the safety requirements regulated by law. The regulations by law are focused especially to reliability and safety oriented aspects of safety relevant systems or components. The contribution deals with the automation of formal processes from design to the generation of reliability-oriented evaluation allowing the consideration of alternatives and appearing conflicts between several additional aspects like cost, spatial needs etc.. During design stage, when relevant system factors are determined, the system architecture is designed, and a function oriented topology tree is generated, the construction of the reliability-oriented structure (topology), which is used to consider the reliability-oriented aspects, can be made.
2010-04-12
Technical Paper
2010-01-0647
Ren-Jye Yang, Ching-Hung Chuang, Yan Fu
Multidisciplinary design optimization (MDO) methods are commonly used for weight reduction in automotive industry. The design variables for MDO are often selected based on critical parts, which usually are close to optimal after many design iterations. As a result, the real weight reduction benefit may not be fully realized due to poor selection of design parameters. In addition, most applications require running design of experiments (DOE) to explore the full design space and to build response surfaces for optimization. This approach is often too costly if too many design variables are simultaneously considered. In this research, an alternative approach to address these issues is presented. It includes two optimization phases. The first phase uses critical parts for design iterations and the second phase use non-critical for weight reduction. A vehicle body structure is used to demonstrate the proposed strategy to show its effectiveness.
2010-04-12
Journal Article
2010-01-0648
Bart F. Zalewski
The response of the engineering system is often obtained by the use of numerical methods such as finite element method or boundary element method. However, the uncertainty of the acquired solutions cannot be measured using conventional methods. This uncertainty is attributed to two sources: errors in mathematical modeling and uncertainties in the parameter. The following paper addresses the second source of uncertainty for the steady state heat conduction problem where the material conductivity is uncertain. Material uncertainty is implemented into fuzzy boundary element method which obtains the exact worst case bounds on the response given the worst case bounds on the parameter uncertainty. The method assumes that a correct partial membership function is given. Numerical examples are shown to illustrate the behavior of the method.
2010-04-12
Journal Article
2010-01-0644
Amandeep Singh, Zissimos P. Mourelatos
Reliability is an important engineering requirement for consistently delivering acceptable product performance through time. As time progresses, the product may fail due to time-dependent operating conditions and material properties, component degradation, etc. The reliability degradation with time may increase the lifecycle cost due to potential warranty costs, repairs and loss of market share. Reliability is the probability that the system will perform its intended function successfully for a specified time interval. In this work, we consider the first-passage reliability which accounts for the first time failure of non-repairable systems. Methods are available in the literature, which provide an upper bound to the true reliability which may overestimate the true value considerably. This paper proposes a methodology to calculate the cumulative probability of failure (probability of first passage or upcrossing) of a dynamic system, driven by an ergodic input random process.
2010-04-12
Technical Paper
2010-01-0684
Kong Byungseok
Invisible Passenger-side Airbag (IPAB) door system must be designed with a weakened area such that the airbag will break through the Instrument Panel (IP) in the intended manner, with no flying debris at any temperature. At the same time, there must be no cracking or sharp edges at the head impact test (ECE 21.01). Needless to say, Head impact test must keep pace with the deployment test. In this paper, we suggested soft airbag door system that is integrally molded with a hard instrument panel by using Two-shot molding. First of all, we set up the design parameters of IPAB door for the optimal deployment and head impact performance by CAE analysis. And then we optimized the open-close time at each gate of the mold so that the soft and hard material could be integrally molded with the intended boundary. We could make the boundary of two materials more constant by controlling the open-close time of each gate with resin temperature sensor.
2010-04-12
Technical Paper
2010-01-0649
Martin Benedikt, Hannes Stippel, Daniel Watzenig
In the automotive industry well-established different simulation tools targeting different needs are used to mirror the physical behavior of domain specific components. To estimate the overall system behavior coupling of these components is necessary. As systems become more complex, simulation time increases rapidly by using traditional coupling approaches. Reducing simulation time by still maintaining accuracy is a challenging task. Thus, a coupling methodology for co-simulation using adaptive macro step size control is proposed. Convergence considerations of the used algorithms and scheduling of domain specific components are also addressed. Finally, the proposed adaptive coupling methodology is examined by means of a cross-domain co-simulation example describing a hybrid electric vehicle. Considerable advantages in terms of simulation time reduction are presented and the trade-off between simulation time and accuracy is depicted.
2010-04-12
Technical Paper
2010-01-0699
Shaiju M. Belsus, Mukul Mitra
In today's world with a dynamic market and varying customer expectations, it becomes inevitable that we find means of recognizing customer needs with all dimensions and instill them as inherent specifications of a product. Automobiles no way fall away from these intangible demands of the changing world, as personal conveyance (car/motorcycle/scooter) nowadays is more of a basic need. It becomes more of challenge to automotive manufacturers, to offer continuously improving quality products, at competitive prices to be in business. It's very important that as automotive designers we recognize quality in its totality and establish a predictive methodology to inculcate quality into the design at early stages of vehicle development.
2010-04-12
Technical Paper
2010-01-0701
Bjorn M. Bergqvist, Mikael Nilsson, Dan Jiresten II
A primary goal within the industry is to shorten the lead time to get shorter time to market and lower cost. System verification can set the limits for how short the lead time can be. Traditionally verification of automotive communication systems like Remote Keyless Entry, RKE, is performed in a complete vehicle late in the product development process. To fulfill the quality demands during the shorter project time Volvo Cars, VCC, has experienced that it is necessary to develop new requirements and verification methods. Six Sigma contains a complete toolbox to do this in a structured and time efficient way. VCC has together with other Ford Motor Company, FMC, brands and the supplier Continental developed methods and requirements so that the RKE system can be verified before vehicles are built. Only a last validation has to be performed in a complete vehicle.
2010-04-12
Technical Paper
2010-01-0697
Efstratios Nikolaidis, Zissimos P. Mourelatos
A complete probabilistic model of uncertainty in probabilistic analysis and design problems is the joint probability distribution of the random variables. Often, it is impractical to estimate this joint probability distribution because the mechanism of the dependence of the variables is not completely understood. This paper proposes modeling dependence by using copulas and demonstrates their representational power. It also compares this representation with a Monte-Carlo simulation using dispersive sampling.
2010-04-12
Technical Paper
2010-01-0698
Alev Osma, Atilla S. Sayginer
The problem-solving cycle is an iterative approach that involves brainstorming, constructing matrices, analyzing and testing until the optimal solution is reached. For the purpose of discovering optimal solutions, some main techniques have been widely used in automotive industry. Despite the use of many problem solving techniques in industrial environment, Team Oriented Problem Solving Methodology-8D, A3 and 5P are well known and have been successfully applied to concerns in automotive industry. The aim of this study is to demonstrate similarities and differences of problem solving methodologies, especially used in automotive industry such as 8D, A3 and 5P. For this purpose, these methodologies have been introduced with generic templates and representing characteristics.
2010-04-12
Journal Article
2010-01-0708
Ed Henshall, Felician Campean
This paper presents an approach to product design verification in which efficient and effective design verification is a key deliverable of a function failure avoidance approach to engineering. The traditional approach to design verification is discussed. The relative advantages of conducting design verification at different levels within the system hierarchy are identified and the manner in which component level testing can be made representative of usage in the field is illustrated within an automotive case study. The use of small samples sizes, a reduced number of tests and a reduction of testing complexity as a part of effective design verification is explained. The role of computer based models as the basis of virtual testing within design verification is discussed.
2010-04-12
Technical Paper
2010-01-0702
Eva Thanasiu, Tim Chanko, Hung-Wen Jen, Carolyn P. Hubbard
Robust on-board diagnosis of emission catalyst performance requires the development of artificially damaged "threshold" catalysts that accurately mimic the performance of damaged catalysts in customer use. The threshold catalysts are used by emissions calibrators to determine fore-aft exhaust oxygen sensor responses that indicate catalyst failure. Rather than rely on traditional trial-and-error processes to generate threshold catalysts, we have used a DFSS (Design For Six-Sigma) approach that explores, at a research level, the relationship between oxygen storage capacity (OSC) of the catalyst (i.e., the fundamental property dictating the response of the aft oxygen sensor) and key process input variables: high-temperature exposure, phosphorus poisoning, and catalyst "recovery."
2010-04-12
Journal Article
2010-01-0696
Amandeep Singh, Zissimos P. Mourelatos
The system response of many engineering systems depends on time. A random process approach is therefore, needed to quantify variation or uncertainty. The system input may consist of a combination of random variables and random processes. In this case, a time-dependent reliability analysis must be performed to calculate the probability of failure within a specified time interval. This is known as cumulative probability of failure which is in general, different from the instantaneous probability of failure. Failure occurs if the limit state function becomes negative at least at one instance within a specified time interval. Time-dependent reliability problems appear if for example, the material properties deteriorate in time or if random loading is involved which is modeled by a random process. Existing methods to calculate the cumulative probability of failure provide an upper bound which may grossly overestimate the true value.
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