Etude de la dynamique d'aube dans l'interaction avec un revêtement abradable par corrélation d'images intégrée

International audienc

A new camera for quantitative measurments of temperature and emissivity during braking

International audienc

Bichromatic thermography developed for thermal field analysis in braking tests

International audienc

An improved Lagrangian thermography procedure for the quantification of the temperature fields within polycrystals

International audiencePolycrystalline metallic materials are made of an aggregate of grains more or less well oriented with respect to the loading axis. During mechanical loading, the diversity of grain orientations leads to a heterogeneous deformation at the local scale. It is well known that most of the plastic work generated during the deformation process reappears in the form of heat, whereas a certain proportion remains latent in the material and is associated with microstructural changes. To access the local stored energy during deformation processes, experimental energy balances are needed at a suitable scale. Thus, simultaneous measurements of thermal and kinematic fields were made in-house at the microstructural scale of a 316L stainless steel submitted to a macroscopic monotonic tensile test. The aim of the present study is to propose a complete calibration strategy allowing us to estimate the thermal variations of each material point along its local and complex deformation path. This calibration strategy is a key element for achieving experimental granular energy balances and has to overcome two major experimental problems: the dynamics of each infrared focal plane array sensor that leads to undesired spatial and temporal noise and the complexity of the local loading path that must be captured by simultaneous complementary measurement. The improvement of such a multifield strategy is crucial for performing properly the experimental and local energy balances required to build new energetically based damage criteria

Microplasticity in Polycrystals: A Thermomechanical Experimental Perspective

International audienceIn this paper, thermomechanical couplings at the grain scale in metallic polycrystals are studied during the deformation process through an original experimental setup and improved calibration tools and full-field treatments. In order to perform intragranular thermomechanical analysis in a metallic polycrystal at the grain scale, a crystallography-based technique for the projection of the temperature and displacement fields on a polynomial basis is proposed. It enables intragranular coupled analysis of strain and temperature full-field data. Macroscopic, mesoscopic and granular analysis are then conducted and it is shown that the determination of a macroscopic yield stress as well as a critical resolved shear stress in grains is possible. Early local microplastic activity is therefore thermomechanically confirmed

Determination of a fatigue crack growth law and the influence of the local plasticity by using Digital Image Correlation

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Simulation of pelvic mobility: topology optimisation of ligamentous system

International audienc

Experimental investigation of elastomer mode I fracture: an attempt to estimate the critical strain energy release rate using SENT tests

International audienceThe resistance to mode I failure of rubbers is studied by submitting single edge notch samples to uniaxial tension. Reproducing the seminal work of Rivlin and Thomas (J Polym Sci 10:291–318, 1953), single edge notch tension specimens, presenting notches of various lengths, are stretched until break. A styrene butadiene rubber, unfilled and filled with carbon-black, and an unfilled rubber from the latter mentioned work, were considered. When the notch is smaller than one fifth of the sample width, mode I crack opening is observed, leading to catastrophic failure that creates smooth mirror-like crack surfaces. Nonetheless, the experimental force-elongation responses show that the mode I critical energy release rate cannot be calculated by a classical Griffith elastic failure analysis. When notches are longer, the SENT samples are not submitted to pure uniaxial tension only. Structural bending leads to uncontrolled mixed mode crack propagation. The surfaces created when the long notches propagate are rough and bifurcations are witnessed for the filled rubbers

The out-of-plane deformation in pure aluminium oligocrystal and its influence on thermographic measurement

International audienc

Méthodologie d'identification de propriétés des composants via les mesures de champs

International audienc