The equivalent reinforced concrete model for simulating the behavior of shear walls under dynamic loading

A new simplified modeling strategy for simulating the non-linear behavior of reinforced concrete structures submitted to severe dynamic shear is presented. The Equivalent Reinforced Concrete model (ERC) uses lattice meshes for concrete and reinforcement bars and uniaxial constitutive laws based on the principles of continuum damage mechanics and plasticity. Verification is provided through comparisons with the results of the NUPEC experimental program. ERC is a simplified method that intends to save computer time and to allow for parametrical studies. The proposed lattice model is promising and could be extended to 3D calculations or to simulate the behavior of plastic zones

A 3D beam element analysis for R/C structural walls

To analyse the real 3D functioning of a structure under seismic loading the dialogue between tests and numerical simulations is needed. Within the framework of the TMR-ICONS research program, dynamic and cyclic tests on U-shaped shear walls have been performed at CEA Saclay and JRC Ispra respectively. More recently, for the French program ìCAMUS 2000î, shaking table tests have been performed on reinforced concrete structural walls. In order to simulate these tests, 3D multi-fiber beam elements are used. Comparison with the experimental results shows the well matching and the limitations of the approach

Modélisation simplifiée pour l'endommagement des structures en béton arme sous sollicitations sévères

La simulation du comportement non-linéaire des voiles en béton armé soumis à des sollicitations sismiques est un problème prioritaire pour la communauté parasismique nationale et internationale. Les séismes récents à Kobe (Japon), Izmit (Turquie) et Athènes (Grèce) ont prouvé encore une fois le rôle primordial que tels éléments jouent pour la sécurité des ouvrages. Recevant la plus grande partie de l'effort sismique, les voiles conditionnent le comportement des structures à murs. Il est donc important de trouver des méthodes numériques adéquates pour simuler le comportement de différents types de voiles souvent rencontrés dans les bâtiments, les installations nucléaires etc. L'équipe « Modélisation des ouvrages sous sollicitations extrêmes » du Laboratoire de Mécanique et de Technologie (LMT) a depuis des années privilégié la recherche vers la mise au point de méthodes simplifiées, fiables et rapides pour le calcul du comportement non linéaire des structures. Pour des voiles ordinaires-élancement supérieur à 1.0-une stratégie de modélisation a été déjà proposée (Mazars et al 1999, Ragueneau 1999). La méthode consiste à utiliser des éléments poutres multicouches de type Bernoulli, capables de simuler le comportement des voiles, dominés par la flexion. La loi constitutive du béton est basée sur la mécanique de l'endommagement. Pour des problèmes de murs d'élancement voisin de 1.0 où le cisaillement est prépondérant, une approche nommée 1.5D a été développée (Dubé 1997). Dans ce cas, des poutres de type Timoshenko sont utilisées et le cisaillement est pris en compte par une contribution non-linéaire des contraintes de cisaillement dans la section. La méthode a été appliquée avec succès pour la modélisation de la maquette NUPEC (élancement 0.7)

Poutre multifibre Timoshenko pour la modélisation de structures en béton armé: Théorie et applications numériques

International audienceLes équations d'un élément poutre 3D multifibre Timoshenko et son utilisation pour la modélisation de structures en béton armé sont ici présentées. L'originalité de l'élément est qu'il a deux nœuds et des fonctions d'interpolation d'ordre supérieur pour éviter les problèmes lies au blocage par le cisaillement. Des exemples numériques comparés avec des résultats expérimentaux montrent la pertinence de l'approche

Poutre 3D multifibre Timoshenko pour la modélisation des structures en béton armé soumises à des chargements sévères

Le développement d'un élément poutre 3D multifibre Timoshenko est ici présenté et son utilisation avec des lois de comportement issues de la mécanique de l'endommagement pour la modélisation des structures en béton armé soumises à des chargements sévères. Le choix est fait pour un élément fini Timoshenko avec deux noeuds et des fonctions de forme d'ordre supérieur afin de gérer les problèmes numériques lies au blocage par le cisaillement. Des exemples numériques comparés avec des résultats expérimentaux montrent la pertinence de l'approche

A Very Intense Neutrino Super Beam Experiment for Leptonic CP Violation Discovery based on the European Spallation Source Linac: A Snowmass 2013 White Paper

Very intense neutrino beams and large neutrino detectors will be needed in order to enable the discovery of CP violation in the leptonic sector. We propose to use the proton linac of the European Spallation Source currently under construction in Lund, Sweden to deliver, in parallel with the spallation neutron production, a very intense, cost effective and high performance neutrino beam. The baseline program for the European Spallation Source linac is that it will be fully operational at 5 MW average power by 2022, producing 2 GeV 2.86 ms long proton pulses at a rate of 14 Hz. Our proposal is to upgrade the linac to 10 MW average power and 28 Hz, producing 14 pulses/s for neutron production and 14 pulses/s for neutrino production. Furthermore, because of the high current required in the pulsed neutrino horn, the length of the pulses used for neutrino production needs to be compressed to a few $\mu$s with the aid of an accumulator ring. A long baseline experiment using this Super Beam and a megaton underground Water Cherenkov detector located in existing mines 300-600 km from Lund will make it possible to discover leptonic CP violation at 5 $\sigma$ significance level in up to 50% of the leptonic Dirac CP-violating phase range. This experiment could also determine the neutrino mass hierarchy at a significance level of more than 3 $\sigma$ if this issue will not already have been settled by other experiments by then. The mass hierarchy performance could be increased by combining the neutrino beam results with those obtained from atmospheric neutrinos detected by the same large volume detector. This detector will also be used to measure the proton lifetime, detect cosmological neutrinos and neutrinos from supernova explosions. Results on the sensitivity to leptonic CP violation and the neutrino mass hierarchy are presented.Comment: 28 page

Interim Design Report

The International Design Study for the Neutrino Factory (the IDS-NF) was established by the community at the ninth "International Workshop on Neutrino Factories, super-beams, and beta- beams" which was held in Okayama in August 2007. The IDS-NF mandate is to deliver the Reference Design Report (RDR) for the facility on the timescale of 2012/13. In addition, the mandate for the study [3] requires an Interim Design Report to be delivered midway through the project as a step on the way to the RDR. This document, the IDR, has two functions: it marks the point in the IDS-NF at which the emphasis turns to the engineering studies required to deliver the RDR and it documents baseline concepts for the accelerator complex, the neutrino detectors, and the instrumentation systems. The IDS-NF is, in essence, a site-independent study. Example sites, CERN, FNAL, and RAL, have been identified to allow site-specific issues to be addressed in the cost analysis that will be presented in the RDR. The choice of example sites should not be interpreted as implying a preferred choice of site for the facility

High intensity neutrino oscillation facilities in Europe

The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fréjus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of μ+ and μ− beams in a storage ring. The far detector in this case is a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular He6 and Ne18, also stored in a ring. The far detector is also the MEMPHYS detector in the Fréjus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. However, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive