8/8/2019 Evaluación de materiales automotrices ligeros

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Automotive LightweightMaterials Assessment

A s a major component of theU.S. Department of Energy’s(DOE’s) Office of FreedomCAR and Vehicle

Technologies Program (FCVT),

Automotive Lightweighting Materials(ALM) focuses on the development andvalidation of advanced materials andmanufacturing technologies tosignificantly reduce automotive vehiclebody and chassis weight withoutcompromising other attributes such assafety, performance, recyclability, andcost. Priority lightweighting materials

include advanced high-strength steels,aluminum, magnesium, titanium, andcomposites including metal-matrixmaterials and glass- and carbon-fiber-reinforced thermosets andthermoplastics. Cost reduction is one of the five research areas that ALM is

pursuing. ORNL has been involved inthis area by addressing the economicviability of new lightweight materialstechnologies over the past severalyears. Numerous process cost modelshave been developed to estimate thecost of lightweight materialstechnologies.

Process Cost ModelingA spreadsheet-based cost modelingframework is used for the cost

estimation of advanced lightweight

materials technologies utilizing theprocess-cost approach. Amanufacturing technology isrepresented as a sequence of individualprocess steps under this approach,

where the output of the first processstep – in terms of total cost and thecosts of individual inputs – becomes aninput to the second production step, andso forth. For each production step, thetotal cost of the product at that step, thecontribution of that production step tothe total cost of the product at that pointin production, and the contribution of each input to the total cost and to thecost of a particular production step canbe estimated. This methodology thereby

allows to identify not only the particular production step but also the inputparameter of a production stepdetrimental to the economic viability of an advanced lightweight materialstechnology.

Figure 1 shows the cost distribution of acarbon fiber reinforced polymer composite body side inner part for light-duty vehicle applications obtained usingthe process-cost modeling approach.

Center for Transportation Analysis(CTA) Research Areas

 Aviation Safety Air Traffic Management Analysis

Data, Statistical AnalysisGeo-Spatial Information Tools

Defense TransportationEnergy Policy Analysis

Environmental Policy AnalysisHighway Safety

Intelligent Transportation SystemsLogistics Management

Supply Chain ManagementModeling and Simulation

Transportation OperationsPlanning and Systems Analysis

Transportation Security

Patricia S. Hu, Director Center for Transportation Analysis

Oak Ridge National Laboratory2360 Cherahala Boulevard

Knoxville, TN 37932865.946.1349

(Fax) 865.946.1314

Website: cta.ornl.gov

Oak Ridge National Laboratory is managedby UT-Battelle, LLC, for the U.S.

Department of Energy under Contractnumber DE-AC05-00OR22725

Center for Transportation Analysis 

Research Brief 

Figure 1. The cost distribution of a carbon fiber 

reinforced polymer composite body part.

61%21%

1%13% 4%

Materials

Capital

Energy

Labor 

Other*

"Other" category includes facility and compliance costs

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Material cost contributes a major share of total partcost, mainly due to the higher carbon fiber cost limitedto military applications today. DOE is currentlyfocusing its carbon fiber R&D activities towards thedevelopment of cost-effective carbon fiber productiontechnologies for a widespread use of it in light-dutyvehicles in the near future.

Life Cycle Analysis

Life cycle analysis is another methodology frequentlyused to determine the viability of lightweight materialsin light-duty vehicle applications. Most lightweightmaterials such as aluminum, magnesium, and polymer composites are either expensive and/or energyintensive to manufacture today. Lightweighting benefitsinclude improved fuel economy which compensates for the increased initial vehicle cost and manufacturingenergy by lower energy use and cost during thevehicle operation life cycle stage. It is estimated thatfuel economy improves by 6.6% per 10% vehicleweight reduction. Life cycle analysis considers allstages from “cradle-to-gate” thereby allowing more

accurate and complete assessment of cost, energy,and emission impacts associated with the adoption of any new lightweight materials technologies.

Several life cycle assessments of lightweightautomotive materials have been completed to date andthey all indicate energy used during vehicle operationdominates the overall life cycle energy use. Figure 2indicates the life cycle energy impacts of stampedsteel versus cast aluminum liftgate inner for light-dutyvehicle applications. Although aluminum poses energypenalty at the manufacturing life cycle stage, but

benefits in subsequent life cycle stages (i.e., use andrecycling) cause a net savings of 1.8 GJ/vehiclecompared to steel.

A recent ORNL study looking at the rolled products for body-in-white applications (in which aluminumprovides the greatest weight saving potentialcompared to steel and ultra-light steel autobody) foundthat it would take about 4 and 10 years, respectively,for aluminum vehicles to achieve a life cycle energyequivalence with steel and ultra-light steel autobody ona single-vehicle basis. A multinational study on thecomparative life cycle assessment of magnesium and

steel front end automotive parts is currently underway,and a similar assessment for carbon fiber polymer composites has also been planned during the fiscalyear 2008.

Research & Development ProgramEvaluationAn evaluation framework has been developed with thegoal of evaluating both short-run outputs and long-runoutcomes of the R&D projects supported by the DOEALM activity. The framework consists of four methodsusing both qualitative and quantitative measures andthey are: qualitative assessment, National ResearchCouncil indicators, quantitative benefits, and benefit-cost analysis. The first three types of benefitsinformation were collected from the project participantsthrough surveys, which assessed their views about thebenefits of projects, including the number of publications produced and graduate studentssupported by the end of a project and long-termbenefits (knowledge level gained through thepublications, human capital investment in graduatestudents’ dissertations and theses produced, andincreased international competitiveness of the Big 3automakers).

The benefit-cost analysis is used to monetize valuesfor the benefits and costs of each project. The benefitsare estimated based on the projected marketpenetration of a specific lightweight materials in light-duty vehicles using a Delphi technique. These four methods complement the benefits matrix developed for DOE’s reports to Congress mandated under theGovernment Performance and Results Act of 1993(GPRA). Our framework besides GPRA requirementsalso includes realized knowledge benefits and costs,yet to be reported to Congress, through the qualitativeassessment (knowledge gains) and through the

coverage of publications and presentations, projectdeliverables, patents and graduate student support.This framework has been applied successfully in thebenefit evaluation of Phase II ALM projects with a totalfunding level of about $60 million.

For more information regarding this research contact Sujit Das, Center for Transportation Analysis,Oak Ridge National Laboratory, phone (865) 946-1222 or email dass@ornl.gov.

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Figure 2. Life cycle energy impacts of stamped steel versus cast liftgate inner for light-duty vehicle applications.