. Dans-ce-cas, La plupart de ces travaux ontétudiéontétudié la découpe dans des conditionséloignéesconditionséloignées des conditions industrielles. En outre, les mesures ont concerné quasiment exclusivement l'´ energie cinétique du poinçon. Peu de travaux présentent la mesure des efforts et notamment l'´ evolution de ces efforts en cours de découpe. Or

. La-connaissance-détaillée-de-l, ´ evolution des efforts de découpe permetégalementpermetégalement d'améliorer la validation de modèles par une corrélation essais/simulation plus riche. Il appara??tappara??t alors utile de continueràcontinuerà réaliser de campagnes d'essais de découpè a grande vitesse dans le

. Dans-cette-optique, Celui-ci permet la mesure de la vitesse du nez du poinçon, l'observation de la zone de cisaillement lors de la découpe ainsi que la mesure de déformations sur un tube de Hopkinson solidaire de la matrice supportant lapì ece cisaillée. Cettedernì ere mesure permet, par un traitement adapté, de remonter aux efforts de découpe. De part leur conception, les outillages présents sur la banc respectent les jeux relatifs poinçon/ matrice généralement utilisés en découpe classique (entre 3 et 10% selon le matériau) Le fait d'utiliser une matrice comportant des variations de section engendre des réflexions des ondes mécaniquesmécaniquesà chaque changement de section. Ceci rend plus délicat le passage de la mesure de déformation sur le tube de HopkinsonàHopkinsonà l'effort de cisaillage appliqué sur cette matrice et implique une calibration du dispositif, Pour cela, nous avons alors eu recoursàrecoursà un deuxì eme dispositif expérimentaí egalement basé sur un dispositif de Hopkinson. Celui-ci permet de ma??triserma??triser l'effort (en durée et en amplitude) imposéimposéà la matrice et ainsi de créer un couple de courbes (effort-déformation) auquel on comparera les déformations mesurées lors d'une découpe

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