Parametric identification of elastic-plastic constitutive laws using spherical indentation

In this paper we present a methodology to characterize elastic-plastic constitutive law of metallic materials using spherical indentation tests and parametric identification coupled with finite elements model simulation. This procedure was applied to identify aluminium, copper and titanium mechanical properties and the identified models show difference that do not exceed 10% with experimental uniaxial tensile tests results. A sensitivity study according to a 2^k Design of Experience (DoE) was achieved to determine which data that can be extracted from pile-up is the most relevant to use in order to enhance the identification procedure. It appears that the maximum pile-up height seems to be the best suited for this purpose

Validation of mechanical damage monitoring on aluminium freestanding thin films using electrical measurements

This paper describes a new technique allowing the monitoring of damage in metallic freestanding thin films during micro-tensile test by using electrical characterization. After a presentation of the set-up, results obtained on aluminium thin coatings by using two calculation methods for damage variable are presented and commented

Caractérisation micromécanique de matériaux en couche mince destinés aux micro- et nano- technologies

The development of micro- and nano- technologies is strongly correlated with the knowledge of the mechanical behavior of constitutive thin coatings. Experimental characterization is mandatory insofar as mechanical properties, at such a scale, are dependent of micro structural features and its history. Moreover, there are numerous implementations of thin coatings. This the sis reports a transversal approach, based on nanoindentation setup, in order to address the characterization of coatings deposited on substrate, and on uni axial tensile tests for freestanding specimens with a thickness less than the micrometer. Particularly, it lies on an itinerant microtensile apparatus, improved and evaluated during this work through campaigns performed on sputtering aluminium with thicknesses down to 700nm and 4µm thick electroplated gold.Le développement des micro- et nano- technologies est aujourd'hui dépendant de la connaissance du comportement mécanique des couches minces constitutives de ces dispositifs. La caractérisation expérimentale des matériaux est primordiale car les propriétés mécaniques se trouvent, à une telle échelle, fortement dépendantes de l'historique de la couche et de sa microstructure. D'autre part, la mise en œuvre de ces couches minces est multiple. Cette thèse présente une approche transversale, s'articulant autour de techniques de nanoindentation, pour caractériser des couches déposées sur substrat, et de traction uniaxiale applicable à des couches minces autoportantes d'épaisseur submicronique. Elle s'appuie notamment sur un concept de platine de microtraction nomade qui a été amélioré et évalué à l'aide d'une mise en œuvre sur des éprouvettes en aluminium pulvérisé d'épaisseur variant entre 700nm et 1,5µm et des éprouvettes d'or électrolytique de 4µm d'épaisseur

Comparative life cycle assessment of intra-row and inter-row weeding practices using autonomous robot systems in French vineyards

International audienc

Analyse du Cycle de Vie des pratiques de désherbage intra-rang et inter-rang avec des systèmes robotisés autonomes dans trois vignobles français

Ce rapport présente les résultats d'une étude ACV menée dans le cadre du projet ROAD (RObotique Agricole Durable) financé par l’Université Clermont Auvergne dans le cadre du Challenge 2 de CAP 2025, thématique AgroTechnologies (programme « Investissements d’Avenir » 16-IDEX-0001 CAP2025). Elle a pour objectif d'évaluer la durabilité environnementale des technologies robotiques dans un contexte agricole. L'étude s'est focalisée sur les pratiques de désherbage intra-rang et inter-rang en viticulture pour trois vignobles français. Les résultats ACV de 26 scénarios de désherbage ont été évalués (7 scénarios en Cognac, 11 scénarios en Languedoc-Roussillon, 9 scenarios en Val de Loire). Des analyses de sensibilité ont été réalisées au regard de la distance de transport des robots, de l'usage de cuivre recyclé pour l’écoconception des robots et de la durée de vie des robots. Une discussion sur les données d'inventaire du cycle de vie comparatives entre tracteurs et robots et des recommandations à destination des utilisations de solutions robotisées en agriculture sont également proposées

A comparative study of microscratch and microtensile adhesion tests for nickel coatings on various substrates

The present paper first focuses on discussing application ranges for the scratch test and the microtensile test. For that purpose, both have been implemented on the same nickel coating plated on several substrates, in particular a PCB, which are expected to have different adhesion behaviors. Afterward, correlations are highlighted between these two types of adhesion tests

Micro Tensile Tests on Aluminium Thin Films: Tensile Device and In Situ Observations

International audienc

Micro Tensile Tests on Aluminium Thin Films: Tensile Device and In Situ Observations

International audienc

Immune responses of phenoloxidase and superoxide dismutase in the manila clam Venerupis philippinarum challenged with Vibrio tapetis - Part I: Spatio-temporal evolution of enzymes' activities post-infection

International audienceManila clams, Venerupis philippinarum (Adams and Reeve, 1850), were experimentally challenged with two Vibrio tapetis strains: CECT4600T, the causative agent of Brown Ring Disease (BRD); and LP2 supposedly non-pathogenic in V.philippinarum. Changes in phenoloxidase (PO) and superoxide dismutase (SOD), two major enzymes involved in immunity, were studied in two tissues, the mantle and hemolymph for 30 days after infection in the extrapallial cavity. Bacterial infection in V.philippinarum resulted in modulation of PO and SOD activities that was both tissue- and time-dependent. A response at early times was detected in the mantle and was associated with significant increases in PO and SOD activities in LP2- and CECT4600T-challenged clams 36 h post injection. This first response in the mantle could be explained by the proximity to the injection region (extrapallial cavity). In the hemolymph the response occurred at later times and was associated with an increase in PO activity and a decrease in SOD activity. As hemolymph is a circulating fluid, this response delay could be due to an "integration time" needed by the organism to counteract the infection. Injections also impacted PO and SOD activities in both tissues and confirmed a difference in pathogenicity between the two V.tapetis strains