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MASS OPTIMIZED HOOD DESIGN FOR CONFLICTING PERFORMANCES

GM Technical Center-Santosh Swamy, Gulshan Noorsumar, Shivakumar Chidanandappa
  • Technical Paper
  • 2019-28-2546
To be published on 2019-11-21 by SAE International in United States
MASS OPTIMIZED HOOD DESIGN FOR CONFLICTING PERFORMANCES Santosh Swamy, Gulshan Noorsumar, Shivakumar Chidanandappa General Motors Technical Center, India Keywords Hood; Head Injury Criterion (HIC); Stiffness; Shape optimization; Multi-Disciplinary Optimization (MDO) Research and/or Engineering Questions/ Objective The objective of this work is to obtain a light weight hood which has least possible mass, and at the same time meets all contradicting performances of pedpro (pedestrian protection) and structural stiffness disciplines. Passenger vehicles have stringent safety norms from pedpro perspective to meet child and adult head injury criteria (HIC). These pedestrian safety requirements often conflict with structural stiffness performance criteria which pose a challenge for most automotive OEMs. Therefore, there is a growing need for mass optimization and performance balancing to meet both the requirements simultaneously. Methodology The outlined method uses a CAE based Multi-Disciplinary Optimization (MDO) approach involving shape variables to find an optimum design for stiffness and pedpro performances. Adding slots along the vertical beam walls of the hood inner panel helps soften the area around the head impact location, thereby improving pedpro performance locally.…
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V2V-Intersection Management at Roundabouts

SAE International Journal of Passenger Cars - Mechanical Systems

GM Technical Center-Priyantha Mudalige
Carnegie Mellon Univ.-Reza Azimi, Gaurav Bhatia, Raj Rajkumar
  • Journal Article
  • 2013-01-0722
Published 2013-04-08 by SAE International in United States
More than 44% of all automotive crashes occur in intersections. These incidents in intersections result in more than 8,500 fatalities and approximately 1 million injuries each year in USA. It is also established that roundabouts are safer than junctions. According to a USDOT study, when compared with the junctions they replaced, roundabouts have 40% fewer vehicle collisions, 80% fewer injuries and 90% fewer serious injuries and fatalities.In earlier work, we have proposed a family of vehicular network protocols, which use Dedicated Short Range Communications (DSRC) and Wireless Access in Vehicular Environment (WAVE) technologies to coordinate a vehicle's movement through intersections. We have shown that vehicle-to-vehicle (V2V) communications can be used to avoid collisions at the intersection and also significantly decrease the trip delays introduced by traffic lights and stop signs. In this paper, we investigate the use of our proposed V2V-intersection protocols for autonomous driving at roundabouts. We have extended our hybrid emulator-simulator called AutoSim to implement realistic map and mobility models to study traffic flow at roundabouts and have implemented our V2V-intersection protocols on…
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Vehicular Networks for Collision Avoidance at Intersections

SAE International Journal of Passenger Cars - Mechanical Systems

GM Technical Center-Priyantha Mudalige
Carnegie Mellon University-Seyed Reza Azimi, Gaurav Bhatia, Ragunathan (Raj) Rajkumar
  • Journal Article
  • 2011-01-0573
Published 2011-04-12 by SAE International in United States
A substantial fraction of automotive collisions occur at intersections. Statistics collected by the Federal Highway Administration (FHWA) show that more than 2.8 million intersection-related crashes occur in the United States each year, with such crashes constituting more than 44 percent of all reported crashes [12]. In addition, there is a desire to increase throughput at intersections by reducing the delay introduced by stop signs and traffic signals. In the future, when dealing with autonomous vehicles, some form of co-operative driving is also necessary at intersections to address safety and throughput concerns.In this paper, we investigate the use of vehicle-to-vehicle (V2V) communications to enable the navigation of traffic intersections, to mitigate collision risks, and to increase intersection throughput significantly. Specifically, we design a vehicular network protocol that integrates with mobile wireless radio communication standards such as Dedicated Short Range Communications (DSRC) and Wireless Access in a Vehicular Environment (WAVE). This protocol relies primarily on using V2V communications, GPS and other automotive sensors to safely navigate intersections and also to enable autonomous vehicle control. Vehicles use DSRC/WAVE…
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Comparison of GREEN-MAC-LCCP© based Indirect CO2-eq. Emissions from MACs and Vehicle Measured Data

GM Technical Center-William Hill
Fiat Group Automobiles S.p.A.-Roberto Monforte
Published 2010-04-12 by SAE International in United States
The European f-Gas Directive phases out HFC-134a from Mobile Air Conditioning systems (MACs) in new vehicles by 2017. In the US pending California and USEPA regulations have incentives to phase out HFC-134a earlier than 2017. As a result industry is striving to transform all global markets to a single new refrigerant in order to simplify global marketing. One of the global tools to help evaluate alternatives during this transition is the global LCCP (Life Cycle Climate Performance) and the development of the GREENMAC- LCCP© model. This model has become the global standard to measure the Life Cycle Analysis (LCA) greenhouse emissions of any proposed alternative refrigerant for MACs starting from bench test results and supporting the car manufacturer choice of the best suitable alternative refrigerant from an environmental perspective.The increasing interest for indirect emissions optimization is affecting not only the new refrigerant selection and also the choice of MACs control in the vehicle. To evaluate system controls, a prototype vehicle equipped with a new MACs, featuring an increased efficiency, must be tested and the results…
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Investigation of Shrink Flanging - Prediction of Wrinkling and Experimental Verification

GM Technical Center-Chuan-Tao Wang
The Ohio State Univ.-Serdar Tufekci, Gary L. Kinzel, Taylan Altan
Published 1994-03-01 by SAE International in United States
Shrink flanging is a major sheet forming operation to produce convex flanges in structural sheet metal components. Flanges are used for appearance, rigidity, hidden joints, and strengthening of the edge of sheet parts such as automobile front fender and complex panels formed by stretch/draw forming. Wrinkling around the flange edge is the major defect in shrink flanging operation. There has been a lack of reliable mathematical modeling to predict the strains and wrinkles in shrink flanging operations. A trial-and-error approach has been usually practiced in tooling and process designs. In this paper, a wrinkling criterion in shrink flange is proposed based on a simplification from a general criterion for a doubly curved anisotropic shell. The mathematical model for strain analysis in shrink flanging is established based on Wang and Wenner's strain model for stretch flange. Shrink flanging experiments were conducted to validate the theories. The mathematical models and failure criteria can be used in practice as design aids and as guidelines for a fast analysis of shrink flanging operations.
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Quality Improvement on an Automobile Fender

GM Technical Center-Chung-Yeh Sa
Published 1990-02-01 by SAE International in United States
One of the fenders made at a GM stamping plant had a long history of quality problems in the form of buckles in the corners of the eyebrow. As a result, the line had a high scrap rate, low uptime and poor stamping quality. The CGA analysis indicated that the prongs on the die prevented metal from being stretched properly. A redesigned die made in Kirksite achieved high panel quality and better material utilization. This paper explains the forming analysis leading to the die changes. The production line has experienced significant quality improvement and lower production costs since the changes were implemented.
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Status of Diesel Particulate Measurement Methods

GM Technical Center-J. Scott MacDonald
Cummins Engine Co.-Syed P. Shahed
Published 1984-02-01 by SAE International in United States
The diesel engine emits exhaust particles that pose a unique set of measurement requirements. To document the state-of-the-art of measurement technology and to improve measurement quality, the Smoke and Particulate Panel of the Diesel Exhaust Composition group of the Coordinating Research Council reviewed published literature and particulate-sampling data generated by panel members to identify (1) the effects of key sampling parameters on measured particulate mass, (2) the causes of measurement variability, (3) the effects of dilution system design on particulate mass measurement, and (4) promising real-time mass measurement methods.The panel found greater measurement difficulty associated with particulates than for gaseous pollutants because of engine-produced variations, the sensitivity of measured particulate mass to dilution parameters, and random errors in the independent measurements which comprise a particulate measurement.Inter-laboratory comparisons showed that measurement variability is influenced by test type, ambient conditions, fuel properties, tailpipe connector design, and dilution system design. Also, greater inter-laboratory measurement variability existed for heavy-duty engines than for light-duty engines. Part of the added variability was due to differences in the dilution techniques used to…
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Matching Case Methodology for Measuring Restraint Effectiveness

GM Technical Center-A.J. Yanik
General Motors Proving Ground-H.D. Pursel, R.W. Bryant, J.W. Scheel
Published 1978-02-01 by SAE International in United States
THE MATCHING CASE METHODOLOGY is a technique for assigning effectiveness values to existing restraint systems.The importance of the matching case methodology is that it utilizes field accident data exclusively - accidents in which a specific restraint was used are compared to accidents of similar injury potential but whose occupants did not use the restraint being evaluated. The resulting average injury values enable the researcher to calculate that restraint system's effectiveness across the various classifications of injury severity. Because the methodology does rely upon accident data, projections of restraint system effectiveness have the potential to come much closer to reality than would be the case if they were dependent primarily upon the theoretical application of laboratory results.Although a portion of the methodology does involve some degree of subjective analysis, close control over the techniques used to implement the methodology should ensure relatively consistent results among any objective groups of trained researchers utilizing similar data banks for analysis.Thus far, the matching case methodology has been applied by General Motors to an early evaluation of the air cushion…
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