Construction of gridshells composed of elastically bent elements and covered by a stretched three-dimensional membrane

This document deals with the gridshells built by the Navier laboratory in the last ten years. The numerical conception is developed, from the draft made by architects up to the final structure. To design a gridshell several numerical tasks have to be performed. The geometry of the gridshell is first considered. Then, an iterative step mixing geometry and mechanical considerations is important. In particular, it is explained how the naturally straight beams are bent to form the final shape. This active bending provides many interests like high stiffness for a light weight structure. After the numerical design of the grid, the geometry of the membrane is drawn from the numerical final geometry of the gridshell. The improvements of gridshells, including safety considerations as well as practical considerations are then developed, trough the four gridshells recently built

Set up of a methodology for participatory plant breeding in bread wheat in France

In Organic Agriculture, cultivation environments and agronomic practices are very diverse. This diversity can be handled with decentralized selection based on the knowledge of farmers and scientists. A collaborative work between associations from Réseau Semences Paysannes and the DEAP team from INRA du Moulon set up an innovative breeding approach on farm based on decentralization and participation of farmers. This approach makes it possible to (i) create new population varieties of bread wheat locally adapted (genetic innovation) (ii) set up an organizational scheme based on decentralization and co construction between actors (societal innovation) and (iii) develop experimental designs, create statistical and data management tools which stimulate these genetic and societal innovations

génération automatique de modèles à base de réseaux de réluctances pour le dimensionnement des dispositifs électromagnétiques

National audienc

Fast transient simulation for actuators

International audienc

Automatic generation of sizing static models based on reluctance networks for the optimization of electromagnetic devices

International audienc

Transformer une caméra conventionnelle en caméra 3D à l'aide d'un composant optique additionnel

International audienceWe propose to add an optical component in front of a conventional camera to improve depth estimation performance of Depth from Defocus (DFD), an approach based on the relation between defocus blur and depth. The add-on overcomes ambiguity and dead zone, which are the fundamental limitations of DFD with a conventional camera, by adding an optical aberration to the whole system which makes the blur unambiguous and measurable for each depth. We look into two optical components: the first one adds astigmatism and the other one chromatic aberration. In both cases we present the principle of the add-on and experimental validations on real prototypes.Nous proposons d'ajouter une composent optique devant une caméra conventionnelle pour améliorer les performances d'estimation de profondeur par estimation du flou de défocalisation (DFD), approche basée sur la relation entre le flou de défocalisation et la profondeur. Le composant additionnel permet d'éviter les problèmes d'ambiguité et de zone aveugle qui sont les principales limitations du DFD avec une caméra conventionnelle, grâce à l'ajout d'une aberration optique au système globale qui rend le flou non ambigue et mesurable pour chaque profondeur. Nous nous intéressons à deux types de composents : le premier ajoute de l'aberration astigmatique et l'autre de l'aberration chromatique. Dans chaque cas, nous présentons le principe du composent et des validations expérimentales sur des prototypes réels