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Cambridge, MA, United States

Volpe, The National Transportation Systems Center or simply Volpe in Cambridge, Massachusetts, is a center of transportation and logistics expertise, operating under the United States Department of Transportation .The Volpe Center is named after Massachusetts Governor and U.S. Secretary of Transportation John Volpe, and its work includes a broad mix of projects that cut across traditional transportation modes and technical disciplines including the Federal Aviation Administration's Enhanced Traffic Management System and Safety Performance Analysis System , and the Federal Motor Carrier Safety Administration's SafeStat Online.The Center assists federal, state, and local governments, industry, and academia in a number of areas of consultation including human factors research, system design, implementation and assessment, global tracking, strategic investment and resource allocation, environmental preservation, and organizational effectiveness.Volpe is part of the U.S. DOT's Research and Innovative Technology Administration. However, it differs from most federal organizations in that it receives no direct appropriation from Congress. Instead, it is funded 100% through a fee-for-service structure in which all costs are covered by sponsored project work . Wikipedia.

Lewis K.C.,Volpe National Transportation Systems Center | Porter R.D.,Environmental Law Institute
Ecological Monographs | Year: 2014

Biofuels are being pursued for their potential greenhouse gas (GHG) emissions benefits, among other reasons. In order to maximize productivity, avoid food-fuel conflicts, and minimize GHG emissions, many advanced biofuel feedstock crops, such as those desired by the aviation community, are under consideration based on traits, such as high biomass and/ or seed production, tolerance of marginal cultivation conditions, and short generation times, that may also be predictors of potential invasiveness risk. Biofuel-related invasion risks can be mitigated through careful feedstock crop selection and cultivation techniques developed from the invasion science literature. Existing voluntary best practices and some state and federal regulatory requirements in the United States recommend and/or require the use of such risk mitigation strategies. However, other policies and programs allow or provide incentives for biofuel production without conditions requiring the use of these strategies. We have synthesized information on the scientific knowledge of invasive species predictors and their use (or absence) in voluntary codes and U.S. regulatory frameworks and incentive programs. We highlight the existing tools and approaches for assessing invasion risk and avoiding the introduction and spread of invasive species as a result of biofuel feedstock cultivation. A wellcoordinated combination of species restrictions, biosecurity requirements, and incentives for selection of less risky biofuel crops may effectively balance the desire for increased biofuel production while minimizing invasion risk. © 2014 by the Ecological Society of America. Source

Van Eikema Hommes Q.,Volpe National Transportation Systems Center
SAE Technical Papers | Year: 2012

ISO 26262 is the first comprehensive automotive safety standard that addresses the safety of the growing number of electric/electronic and software intensive features in today's road vehicles. This paper assesses the standard's ability to provide safety assurance. The strengths of the standard are: (1) emphasizing safety management and safety culture; (2) prescribing a system engineering development process; (3) setting up a framework for hazard elimination early in the design process; (4) disassociating system safety risk assessment from component probabilistic failure rate. The third and fourth strengths are noteworthy departure from the philosophy of IEC61508. This standard has taken much-needed and very positive steps towards ensuring the functional safety of the modern road vehicles. SAE publications from industry show a lot of enthusiasm towards this standard. This paper suggested a number of items to be considered further strengthen the standard's ability to provide safety assurance. First, the Automotive Safety Integrity Level (ASIL) assessment may want to consider only the severity level, so that the subjectivity involved in likelihood assessment is eliminated. The ASIL assessment also needs to be standardized across manufacturers in order to address the tension between safety and business competitiveness. Government, industry consortium, and research institutions may want to work together on ASIL standardization efforts. Second, this standard provides little guidance on how to eliminate hazards in the design, but rather provides details on how to design and evaluate the effectiveness of component failure detection and control mechanisms. This paper identifies research that could be conducted on how to adapt the System Theoretic Accident Modeling and Process model during the design phase. Third, this standard gives detailed guidance on reliability engineering methods for component failures, but little on system safety design methods. Reliability and safety are different attributes of the system. This standard can be improved by further research on adapting system safety engineering methods to this standard. Fourth, the standard also substitutes good software systems engineering practices for software safety, although this is on par with other industry standards. Further research is needed to address software safety assurance. Fifth, the need for more detail in the safety assurance process and plan for product and operation phases of the product are discussed. Last, the needs for better design methods and safety assurance plan concerning driver/vehicle interaction design are also presented. Source

Hastings A.L.,Volpe National Transportation Systems Center
INTER-NOISE 2015 - 44th International Congress and Exposition on Noise Control Engineering | Year: 2015

Auralization of moving sources provides a practical method to generate large and varied stimuli sets that can be used to help one understand the implications of specific sound generation parameters for human subject experiments and for public outreach. A practical approach is described that includes free field propagation, Doppler shifting via interpolation of the time-delayed source signal, and localization through the use of discrete head-related transfer functions with weighted averaging to produce continuous changes in position. The approach assumes a stationary receiver but makes no assumptions on the trajectory of the source. The method is sufficiently straightforward and abstract to allow easy extension, and simulation times are short enough for extensive experimentation. © 2015 by ASME. Source

Llana P.,Volpe National Transportation Systems Center
2015 Joint Rail Conference, JRC 2015 | Year: 2015

The Office of Research, Development, and Technology of the Federal Railroad Administration (FRA) and the Volpe Center are continuing to evaluate new technologies for increasing the safety of passengers and operators in rail equipment. The results of vehicle-to-vehicle override, where the strong underframe of one vehicle, typically a locomotive, impacts the weaker superstructure of the other vehicle, can be devastating. Crashworthy components which can be integrated into the end structure of a locomotive have been developed to inhibit override in the event of collision. Recent research has resulted in the development of a design concept, including evaluation with finite-element analysis (FEA), fabrication, and component tests. The design concept developed incorporates two key components: a push-back coupler and a deformable anti-climber. Detailed designs for these components were developed and the performance of the designs was evaluated through large deformation dynamic FEA. Test articles were fabricated and dynamically tested to verify their individual performance characteristics. The tests were successful in demonstrating the required performance of the components. Test results were consistent with finite element model predictions of energy absorption capability, force-displacement behavior, and modes of deformation. Work is ongoing to retrofit these crashworthy components onto conventional locomotives and conduct full-scale dynamic impact tests of colliding cars, as well as colliding trains. Service tests will be performed to measure the impact speed at which push-back coupler triggering occurs. Vehicle-to-vehicle tests will be conducted to demonstrate the performance of the crashworthy components working together as an integrated system. The vehicle-to-vehicle tests will also allow an evaluation of the crashworthiness compatibility of a modified locomotive with a range of equipment, including conventional locomotives, cab cars, and freight cars. Train-to-train tests are planned to demonstrate incremental improvement, increased crashworthiness, compatibility, and serviceability. This paper describes the tests that are planned to demonstrate the behavior of these components when they are integrated into the end structure of a locomotive. The tests will demonstrate the in-service and crashworthiness performance of the modified locomotives. This research program endeavors to advance locomotive crashworthiness technology and develop the technical basis for generating specifications for push-back couplers and deformable anti-climbers. Source

Yu H.L.,MacroSys Research and Technology LLC | Jeong D.Y.,Volpe National Transportation Systems Center
Theoretical and Applied Fracture Mechanics | Year: 2010

Nonlinear dynamic finite element analysis (FEA) is conducted to simulate the fracture of unnotched Charpy specimens of steel under pendulum impact loading by a dedicated, oversized and nonstandard Bulk Fracture Charpy Machine (BFCM). The impact energy needed to fracture an unnotched Charpy specimen in a BFCM test can be two orders of magnitude higher than the typical impact energy of a Charpy V-notch specimen. To predict material failure, a phenomenological, stress triaxiality dependent fracture initiation criterion and a fracture evolution law in the form of strain softening are incorporated in the constitutive relations. The BFCM impact energy results obtained from the FEA simulations compare favorably with the corresponding experimental data. In particular, the FEA predicts accurately the correlations of the BFCM impact energy with such factors as specimen geometry, impactor tup width and material type. The analyses show that a specimen's progressive deterioration through the thickness dimension displays a range of shear to ductile fracture modes, demonstrating the necessity of applying a stress state dependent fracture initiation criterion. Modeling the strain softening behavior helps to capture the residual load carrying capability of a ductile metal or alloy beyond the onset of damage. The total impact energy can be significantly under predicted if a softening branch is not included in the stress-strain curve. This research supports a study of the puncture failure of railroad tank cars under dynamic impact loading. Applications of the presented fracture model in failure analyses of other structures are further discussed. © 2010. Source

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