The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Erwan Verron - One of the best experts on this subject based on the ideXlab platform.
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Fatigue damage in carbon black filled natural rubber under uni- and multiaxial loading conditions
International Journal of Fatigue, 2013Co-Authors: Jean-benoit Le Cam, Bertrand Huneau, Erwan VerronAbstract:This paper deals with fatigue damage in carbon black filled natural rubber under uni- and multiaxial loading conditions. Fatigue damage is described at both the Macroscopic (mechanical) scale and the microscopic (material) scale. The different fatigue damages observed at the Macroscopic scale are presented according to the prescribed loading conditions. At this scale, five elementary fatigue damage patterns are defined, three correspond to external Macroscopic cracks and two correspond to internal Macroscopic cracks. These elementary fatigue damage patterns are investigated at the microscopic scale by distinguishing crack initiation and crack growth. Results show that the cracks initiate from microstructural defects, whose mean diameter does not exceed 400 mu m and that crack initiation at the Macroscopic scale corresponds to crack growth at the microscopic scale, which validates recent energetic approaches adopted to predict fatigue crack initiation in rubbers. The morphology of fracture surfaces exhibits two types of features: wrenchings and fatigue striations. In particular, results highlight that several shapes of fatigue striations can form, depending on the loading conditions, and that several mechanisms of fatigue striation formation could come into play.
Jorge A Laval - One of the best experts on this subject based on the ideXlab platform.
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microscopic modeling of the relaxation phenomenon using a Macroscopic lane changing model
Transportation Research Part B-methodological, 2008Co-Authors: Jorge A Laval, Ludovic LeclercqAbstract:A crucial challenge faced by current microscopic traffic flow models is capturing the relaxation phenomena commonly observed near congested on-ramps: vehicles are willing to accept very short spacings as they enter the freeway, but "relax" to more comfortable values shortly thereafter. This paper introduces a framework to solve this problem using a Macroscopic theory of vehicle lane-changing inside microscopic models. In this theory, lane changes take place according to a stochastic process that has been validated in the field, and whose mean value is a function of lane-specific Macroscopic quantities. As a consequence, the lane-changing logic becomes very simple compared to existing microscopic lane-changing models, and requires only one extra parameter. The resulting microscopic model is validated with empirical data.
Jean-benoit Le Cam - One of the best experts on this subject based on the ideXlab platform.
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Fatigue damage in carbon black filled natural rubber under uni- and multiaxial loading conditions
International Journal of Fatigue, 2013Co-Authors: Jean-benoit Le Cam, Bertrand Huneau, Erwan VerronAbstract:This paper deals with fatigue damage in carbon black filled natural rubber under uni- and multiaxial loading conditions. Fatigue damage is described at both the Macroscopic (mechanical) scale and the microscopic (material) scale. The different fatigue damages observed at the Macroscopic scale are presented according to the prescribed loading conditions. At this scale, five elementary fatigue damage patterns are defined, three correspond to external Macroscopic cracks and two correspond to internal Macroscopic cracks. These elementary fatigue damage patterns are investigated at the microscopic scale by distinguishing crack initiation and crack growth. Results show that the cracks initiate from microstructural defects, whose mean diameter does not exceed 400 mu m and that crack initiation at the Macroscopic scale corresponds to crack growth at the microscopic scale, which validates recent energetic approaches adopted to predict fatigue crack initiation in rubbers. The morphology of fracture surfaces exhibits two types of features: wrenchings and fatigue striations. In particular, results highlight that several shapes of fatigue striations can form, depending on the loading conditions, and that several mechanisms of fatigue striation formation could come into play.
Ludovic Leclercq - One of the best experts on this subject based on the ideXlab platform.
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microscopic modeling of the relaxation phenomenon using a Macroscopic lane changing model
Transportation Research Part B-methodological, 2008Co-Authors: Jorge A Laval, Ludovic LeclercqAbstract:A crucial challenge faced by current microscopic traffic flow models is capturing the relaxation phenomena commonly observed near congested on-ramps: vehicles are willing to accept very short spacings as they enter the freeway, but "relax" to more comfortable values shortly thereafter. This paper introduces a framework to solve this problem using a Macroscopic theory of vehicle lane-changing inside microscopic models. In this theory, lane changes take place according to a stochastic process that has been validated in the field, and whose mean value is a function of lane-specific Macroscopic quantities. As a consequence, the lane-changing logic becomes very simple compared to existing microscopic lane-changing models, and requires only one extra parameter. The resulting microscopic model is validated with empirical data.
E Weinan - One of the best experts on this subject based on the ideXlab platform.
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heterogeneous multiscale method for the modeling of complex fluids and micro fluidics
Journal of Computational Physics, 2005Co-Authors: E WeinanAbstract:The framework of the heterogeneous multiscale method (HMM) is used to develop numerical methods for the study of macroscale dynamics of fluids in situations, where either the constitutive relation or the boundary conditions are not explicitly available and have to be inferred from microscopic models such as molecular dynamics. Continuum hydrodynamics is used as the Macroscopic model, while molecular dynamics serves as the microscopic model and is used to supply the necessary data, e.g., the stress or the boundary condition, for the Macroscopic model. Scale separation is exploited so that the Macroscopic variables can be evolved in Macroscopic spatial/temporal scales using data that are estimated from molecular dynamics simulation on microscale spatial/temporal domains. This naturally decouples the micro and macrospatial and temporal scales whenever possible. Applications are presented for models of complex fluids, contact line dynamics, and a simple model of non-trivial fluid-solid interactions.
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heterogeneous multiscale method a general methodology for multiscale modeling
Physical Review B, 2003Co-Authors: E Weinan, Bjorn Engquist, Zhongyi HuangAbstract:The heterogeneous multiscale method, is presented as a general methodology for an efficient numerical computation of problems with multiple scales. The method relies on an efficient coupling between the Macroscopic and microscopic models. In case the Macroscopic model is not explicitly available or is invalid in part of the domain, the microscopic model is used to supply the necessary data for the Macroscopic model. Scale separation is exploited so that coarse-grained variables can be evolved on Macroscopic spatial/temporal scales using data that are predicted based on the simulation of the microscopic process on microscale spatial/temporal domains. Applications to homogenization, dislocation dynamics and crack propagation are discussed.
