The Impact of Clustering in the Performance Prediction of Transportation Infrastructures

2021 ◽  
pp. 803-814
Author(s):  
Carlos Santos ◽  
Sérgio Fernandes ◽  
Mário Coelho ◽  
José C. Matos
Keyword(s):  
Performance Prediction ◽  
Transportation Infrastructures ◽  
The Impact

The Use of Laboratory-Measured and Strain-Gauge Backcalculated Asphalt Stiffness for Rutting Performance Prediction

2019 ◽  
Vol 2673 (3) ◽  
pp. 323-333
Author(s):  
Erdem Coleri ◽  
John T. Harvey
Keyword(s):  
Performance Prediction ◽  
Strain Gauge ◽  
Asphalt Concrete ◽  
Laboratory Tests ◽  
Concrete Materials ◽  
Long Term Performance ◽  
Term Performance ◽  
The Impact

Laboratory tests are conducted with asphalt concrete materials to determine the expected in-situ performance. In addition, laboratory test results are commonly used in mechanistic-empirical design methods for material characterization to improve the predictive accuracy of the models. However, the effectiveness of laboratory tests in characterizing the long-term performance of asphalt concrete materials needs to be validated to be able to use the results for pavement design and long-term performance prediction. Inaccurate performance characterization and prediction can directly affect the decision-making process for pavement maintenance, rehabilitation, and reconstruction and result in unexpected early failures in the field. The major objective of this study is to determine the impact of using laboratory-measured asphalt stiffness on the prediction accuracy of mechanistic-empirical models. In addition, the effect of using linear-elastic modeling assumptions (layered elastic theory) and neglecting the nonlinearity of pavement response at high load levels (and/or at high strain levels for weaker structures) on the predicted rutting performance was determined. In this study, the effectiveness of the use of laboratory asphalt stiffness tests for in-situ asphalt stiffness characterization was determined by comparing the rutting performance predicted using laboratory-measured stiffness to rutting predicted using strain-gauge backcalculated stiffness. It was determined that laboratory tests are able to characterize the in-situ stiffness characteristics of the asphalt mix used in this study and the stiffness characterization process suggested in this study can provide reliable rutting performance predictions. Results of this study are only applicable to tested rubberized asphalt concrete mixtures.

scholarly journals PageRank centrality for performance prediction: the impact of the local optima network model

2017 ◽  
Vol 24 (3) ◽  
pp. 243-264 ◽  
Author(s):  
Sebastian Herrmann ◽  
Gabriela Ochoa ◽  
Franz Rothlauf
Keyword(s):  
Network Model ◽  
Performance Prediction ◽  
Local Optima ◽  
Pagerank Centrality ◽  
The Impact

scholarly journals Development of Tolerance-Based Performance Prediction Technology and Optimization of Actuator Design Factors of a Magnet Vertical Magnetization of AVAS

2021 ◽  
Vol 11 (6) ◽  
pp. 2505
Author(s):  
Hyun-Ju Lee ◽  
Dong-Shin Ko ◽  
Deog-Jae Hur
Keyword(s):  
Permanent Magnet ◽  
Performance Prediction ◽  
Electromagnetic Force ◽  
Magnetic Circuit ◽  
Plate Thickness ◽  
Optimization Method ◽  
Design Parameters ◽  
Alerting System ◽  
Multiple Variables ◽  
The Impact

With the increasing proliferation of electric and hydrogen vehicles, noises to recognize the driving status at low speeds are legalized, so a virtual engine sound generator is required, and slimming is required for packaging it in vehicles. This study investigates an optimization method for improving the electromagnetic force performance and slimming of the magnetic circuit for the permanent magnet structure for the vertical magnetization of the actuator for the acoustic vehicle alerting system (AVAS) of a vehicle and the probabilistic optimization of manufacturing tolerance management. To investigate the impact of the design parameters of the magnetic circuit structure on the electromagnetic force performance and slimming, we performed an independent analysis based on a single variable and investigated the characteristic variations based on multiple variables using a full factorial design and derived a performance prediction regression model using the central composite design of response surface methodology, including the curvature effect, by adding a center point to verify and consider the nonlinear characteristics. Consequently, four effective design parameters were determined to analyze the electromagnetic force performance and slimming of the vertical magnetization structure of the AVAS actuator—permanent magnet thickness, magnetic force collecting plate thickness, yoke position, and yoke thickness. We then performed statistical analysis using Monte Carlo simulation and proposed an optimization management level of 3σ with excellent process capability as the design application tolerance that can occur in the manufacturing process of each design parameter, whereby the confidence level of electromagnetic force performance and slimming improved from 99.46% to 99.73% and 97.62% to 99.73%, respectively.

scholarly journals Quantifying the Effects of Climate Change on Pavement Performance Prediction using AASHTOWare Pavement ME Design

2020 ◽  
Author(s):  
Md Shahjalal Chowdhury
Keyword(s):  
Climate Change ◽  
Performance Prediction ◽  
Temperature Increase ◽  
Pavement Performance ◽  
Effect Of Temperature ◽  
Climatic Data ◽  
Temperature Changes ◽  
State Highway ◽  
Air Temperatures ◽  
The Impact

Climate change is one of the most concerning global issues and has the potential to influence every aspect of human life. Like different components of society, it can impose significant adverse impacts on pavement infrastructure. Although several research efforts have focused on studying the effects of climate change on natural and built systems, its impact on pavement performance has not been studied as extensively. The primary objectives of this thesis research was to quantify the effect of temperature changes on flexible pavement response and performance prediction using the AASHTOWare Pavement ME Design (PMED), and quantify the effects of Local Calibration Factors (LCFs) used by different state highway agencies in the United States on predicted pavement performance. Particular emphasis was given to LCF values used by the Idaho Transportation Department. The climatic data, as well as LCFs corresponding to several different states, were used to identify how different LCF values affect pavement performance prediction. The effects of atmospheric temperature changes on pavement temperature and Asphalt Concrete (AC) layer modulus were studied by analyzing the intermediate files generated by PMED. Finally, the impact of temperature change on AC dynamic modulus (E*) was also analyzed to link the PMED-predicted distresses with asphalt mix properties. Historical climatic data was obtained from the Modern-Era Retrospective Analysis for Research and Applications (MERRA) database. Projected data considered to simulate the temperature changes in the future were generated by adopting two different approaches: (1) Manual alteration of historical temperature distribution data to represent scenarios with increased mean and standard deviation values; and (2) Use of temperature data projected by established Global Climate Models (GCM). All different climatic scenarios were used in PMED along with a standard pavement section, and the distresses predicted over the design life of the pavement were compared. Simulation results showed consistent increase in Total Pavement rutting and AC rutting with increasing air temperatures. The effect of temperature increase on AC thermal cracking predicted by PMED demonstrated inconsistent trends. In contrast, the projected temperature increase had no significant effect on bottom-up fatigue cracking for the chosen study locations. It was found that the impact of changed air temperatures can be different for pavement sections constructed in different geographic locations. Moreover, the analysis confirmed that the Local Calibration Factors (LCFs) established by different state highway agencies played a major role in governing the effect of future temperature increase on predicted pavement performance. Through an extensive study of the LCFs used in the states of Idaho, Colorado, and Michigan, it was observed that the LCFs in Idaho did not adequately reflect the effects of future temperature changes on predicted pavement performance. Findings from this study emphasize the importance of considering non-stationary climate conditions likely to occur in the future during the process of pavement design. Moreover, this study also highlighted different aspects of the LCFs that play a significant role in capturing the effects of climatic factors on pavement performance predicted by PMED. Based on the findings, it is believed that further fine-tuning of the LCFs used in Idaho may be needed.

Characterizing the Influence of Impeller Exit Recirculation on Centrifugal Compressor Work Input

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Charles Stuart ◽  
Stephen Spence ◽  
Dietmar Filsinger ◽  
Andre Starke ◽  
Sung In Kim
Keyword(s):  
Performance Prediction ◽  
Pressure Rise ◽  
Flow Region ◽  
Single Equation ◽  
Flow Coefficient ◽  
Physical Treatment ◽  
Recirculating Flow ◽  
Work Input ◽  
Stage Performance ◽  
The Impact

Impeller recirculation is a loss which has long been considered in one-dimensional (1D) modeling; however, the full extent of its impact on stage performance has not been analyzed. Recirculation has traditionally been considered purely as a parasitic (or external) loss, i.e., one which absorbs work but does not contribute to total pressure rise across the stage. Having extensively analyzed the impact of recirculation on the impeller exit flow field, it was possible to show that it has far-reaching consequences beyond that of increasing total temperature. The overall aim of this package of work is to apply a much more physical treatment to the impact of impeller exit recirculation (and the aerodynamic blockage associated with it) and hence realize an improvement in the 1D stage performance prediction of a number of turbocharger centrifugal compressors. The factors influencing the presence and extent of this recirculation are numerous, requiring detailed investigations to successfully understand its sources and to characterize its extent. A combination of validated three-dimensional computational fluid dynamics (CFD) data and gas stand test data for six automotive turbocharger compressor stages was employed to achieve this aim. In order to capture the variation of the blockage presented to the flow with both geometry and operating condition, an approach involving the impeller outlet to inlet area ratio and a novel flow coefficient term were employed. The resulting data permitted the generation of a single equation to represent the impeller exit blockage levels for the entire operating map of all the six compressor stages under investigation. With an understanding of the extent of the region of recirculating flow realized and the key drivers leading to its creation identified, it was necessary to comprehend how the resulting blockage influenced compressor performance. Consideration was given to the impact on impeller work input through modification of the impeller exit velocity triangle, incorporating the introduction of the concept of an “aerodynamic meanline” to account for the reduction in the size of the active flow region due to the presence of blockage. The sensitivity of the stage to this change was then related back to the level of backsweep applied to the impeller. As a result of this analysis, the improvement in the 1D performance prediction of the six compressor stages is demonstrated. In addition, a number of design recommendations are presented to ensure that the detrimental effects associated with the presence of impeller exit recirculation can be minimized.

High-Performance Impact-Resistant Concrete Mixture for Transportation Infrastructure Applications

2019 ◽  
Vol 2673 (12) ◽  
pp. 628-635 ◽  
Author(s):  
Kamal Baral ◽  
Jovan Tatar ◽  
Qian Zhang
Keyword(s):  
Energy Absorption ◽  
High Performance ◽  
Impact Resistance ◽  
Absorption Capacity ◽  
Flexural Behavior ◽  
Cementitious Composites ◽  
Repeated Impact ◽  
Energy Absorption Capacity ◽  
Transportation Infrastructures ◽  
The Impact

Engineered cementitious composites (ECC) is a class of high-performance fiber-reinforced cementitious composites featuring metal-like strain-hardening behavior under tension and high ductility. The highly ductile behavior of ECC often results in high impact resistance and energy absorption capacity, which make ECC suitable for applications in structures that are prone to impact damages, like exterior bridge girders, bridge piers, and crash barriers. In a recent study, a new ECC mixture has been developed using domestically available polyvinyl alcohol (PVA) fibers and regular river sand in replacement of imported PVA fibers and fine silica sand that are normally used in other ECC mixtures. The newly developed mixture, with improved local accessibility of raw materials, enables structural-scale applications of ECC in transportation infrastructures. To evaluate the suitability of the mixture for impact-resistant structures, in this paper, the tensile and flexural behavior of the newly developed material were characterized under pseudo-static loading and high strain-rate loadings up to 10−1 s−1. Direct drop-weight impact test was also conducted to assess the impact resistance and energy absorption capacity of the material. It was ensured that the ECC mixture maintains high tensile strain capacity above 1.8% under all tested strain rates. Regarding the damage characteristics, energy absorption capacity and load-bearing capacity during repeated impact loadings, ECC was found to have 75% higher energy dissipation capacity compared with regular reinforced concrete specimens and superior damage tolerance. The research results demonstrated that the newly developed ECC has a great potential to improve the impact resistance of transportation infrastructures.

CFD Modeling Effects on Unsteady Multistage Simulation for a Transonic Axial Compressor

2011 ◽  
Author(s):  
Mai Yamagami ◽  
Hidekazu Kodama ◽  
Dai Kato ◽  
Naoki Tsuchiya ◽  
Yasuo Horiguchi ◽  
...  
Keyword(s):  
Performance Prediction ◽  
High Speed ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Turbulence Models ◽  
Numerical Approach ◽  
Path Model ◽  
Cfd Modeling ◽  
Geometry Modeling ◽  
The Impact

Unsteady three-dimensional multistage calculations are performed for a highly loaded, high-speed axial compressor to investigate the impact of real geometry modeling and different numerical approaches on the accuracy of the performance prediction. First, two features of the real geometries are separately compared with the calculation which consists of a pure flow path model except that rotor tip clearances are considered. One treats leakage generated by part gaps between variable stator vanes and the annulus lines. Another incorporates seal cavities to model leakage underneath the shrouded stators. Then, the influence of different numerical approach with different turbulence models is also investigated. Discussion on the impact of the CFD modeling on the performance prediction focuses on the prediction accuracies of stage operating points and spanwise mixing. It is suggested that a realistic simulation of turbulent-type flow unsteadiness in a multistage machine is important for an accurate prediction of spanwise mixing phenomena.

scholarly journals Practical Consistency of Ethernet-Based QoS with Performance Prediction of Heterogeneous Microwave Radio Relay Transport Network

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 913
Author(s):  
Slađan Zlatar ◽  
Vlatko Lipovac ◽  
Adriana Lipovac ◽  
Mirza Hamza
Keyword(s):  
Performance Prediction ◽  
Access Network ◽  
Real Life ◽  
Transport Network ◽  
Base Stations ◽  
Main Task ◽  
Synchronous Digital Hierarchy ◽  
Generation Network ◽  
The Impact

Microwave line-of-sight radio relay (RR) systems are a constitutive part of a telecom operator transport network, as an alternative to optical transmission systems when the latter are not technically possible or rational to implement. Nowadays, RR links are quite often used in the access network for connecting mobile radio base stations, thus also enabling traffic aggregation, and so on. In this paper, we focus on a practical, real-life, five-section heterogeneous RR network, comprising classic synchronous digital hierarchy (SDH) and SDH new generation network (NGN) architecture, hybrid parallel and mutually independent transmission of native Ethernet and TDM services, and all-IP network parts. Specifically, the main task of this work is to answer whether such a diverse RR system could satisfy the quality norms for Ethernet-based services, meaning whether a tolerable RR unavailability will necessarily imply the according Ethernet quality of service (QoS) degradation. This question is addressed by the comprehensive in-service and out-of-service testing of an operational hybrid RR transmission system. After extensive practical testing and appropriate analysis of the achieved results, it came out that the impact of RR-level impairments that determine the performance prediction affected the Ethernet QoS to the extent that BER values increased to the acceptability threshold values. We believe that the preliminary results reported here could serve as a hint and a framework for a more comprehensive cross-layer test strategy in terms of both test diversity and repeating rate, which contemporary network operators need to implement in order to enable the appropriate quality of experience for users of their services.

Sign in / Sign up

Export Citation Format

Share Document