La qualité du logement est indissociable de celle de la ville

Le logement collectif est la matière première de nos villes. Il est marqué par le savoir-faire, les matériaux, les pratiques constructives et administratives locales. Il dépend de l’état de la demande, de la disponibilité du sol et des contraintes de l’économie. Il façonne notre environnement et affecte notre manière de vivre non seulement au niveau de notre cadre intime mais jusqu’à notre rapport à l’espace public. On peut parler d’une culture urbaine, d’une identité de lieu façonnée par la pratique locale et l’expérience du logement collectif

Few problems with regularized Coulomb law

The main idea is to present some problems where the friction obeys to regularized Coulomb law. Mathematically, it is usual that the friction law is supposed to be the Coulomb law which is controlled by a function “sign” with discontinuity at the origin. In reality, friction phenomenon corresponds to an average continuous behavior. From a modelling point of view, the simplest way to get this continuity is to regularize friction law. Obviously, friction problems become more complicated due to the fact that the friction law exhibits two phases of behavior. Solving problems with this friction law could bring some special results. To present them, the problems considered in this paper are related to the bending of two beams in contact under a certain pressure and to the transversal strain of an elastic thin strip in contact with a rigid body. For these two problems, analytical solutions are presented and also some finite element simulations for comparison

Survivability of integrated PVDF film sensors to accelerated ageing conditions in aeronautical/aerospace structures

This work validates the use of integrated polyvinylidene fluoride (PVDF) film sensors for dynamic testing, even after being subjected to UV-thermo-hygro-mechanical accelerated ageing conditions. The verification of PVDF sensors' survivability in these environmental conditions, typically confronted by civil and military aircraft, is the main concern of the study. The evaluation of survivability is made by a comparison of dynamic testing results provided by the PVDF patch sensors subjected to an accelerated ageing protocol, and those provided by neutral non-aged sensors (accelerometers). The available measurements are the time-domain response signals issued from a modal analysis procedure, and the corresponding frequency response functions (FRF). These are in turn used to identify the constitutive properties of the samples by extraction of the modal parameters, in particular the natural frequencies. The composite specimens in this study undergo different accelerated ageing processes. After several weeks of experimentation, the samples exhibit a loss of stiffness, represented by a decrease in the elastic moduli down to 10%. Despite the ageing, the integrated PVDF sensors, subjected to the same ageing conditions, are still capable of providing reliable data to carry out a close followup of these changes. This survivability is a determinant asset in order to use integrated PVDF sensors to perform structural health monitoring (SHM) in the future of full-scale composite aeronautical structures