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3 Ergebnisse
Bereich: Suchergebnisse
Publikation Cartes itérées appliquées à un instrument de type clarinette(04/2010) Taillard, Pierre-André; Kergomard, Jean; Laloë, Franck; Karkar, SamiMc Intyre et coll. (1983) ont montré que l’on peut ramener le calcul des oscillations d’une clarinette à une simple itération, dans un modèle où le résonateur est cylindrique avec des pertes indépendantes de la fréquence, et où l’anche est vue comme un ressort sans inertie. Pour cela on choisit le couple des ondes aller et retour comme variables de base, et le système peut se ramener à l’itération d’une fonction f(x) qui relie les amplitudes de ces ondes, conduisant à des oscillations en signaux carrés. Nous donnons une étude plus approfondie de cette fonction et en déduisons un encadrement des valeurs des paramètres d’excitation pour lesquelles l’anche peut battre, ou encore pour lesquelles le signe du débit peut s’inverser. Les fonctions itérées de la fonction f(x) renseignent notamment sur la stabilité des régimes périodiques, ou aident à comprendre l’existence de régimes chaotiques, de fenêtres de périodicité ou d’intermittences.06 - PräsentationPublikation Numerical Computation of the Transfer Functions of an Axisymmetric Duct with the Extended Discrete Singular Convolution Method(08.07.2014) Taillard, Pierre-André; Hélie, Thomas; Bensoam, JoëlThis work takes part of the "cagima" project (supported by the ANR) which investigates the defects of the tuning of reed musical instruments as well as their homogeneity of emission and timbre. The goal consists in replacing the traditional approach adopted by instrument makers by a global and rational approach in the design of new instruments /ab initio/ (called "logical instruments"), minimizing some identi ed defects. In this context, an interactive virtual model, predictive and con gurable is proposed. Several approaches are available in the literature but the main di culty is to design digital instruments that are accurate (according to measurements) and that can be implemented in real-time. In this paper, an approach based on the Extended Discrete Singular Convolution method (EDSC) is proposed. The temporal operator (including the fractional derivative term for viscothermal losses) is implemented according to the EDSC formalism. The method allows a fast, straightforward and accurate computation of the transfer functions of an axisymmetric duct with an arbitrary pro le. The computation of the case where the losses are dependent from the diameter causes no noticeable di culty. The results are compared to measurements of a trombone bell.06 - PräsentationPublikation Scraping technique for clarinet reeds derived from a static bending(26.04.2012) Taillard, Pierre-André; Dalmont, Jean-PierreReed scraping is an art mastered only by a few clarinettists. The published empirical methods do not agree on how to determine where to scrape. In order to understand the problematic more clearly, a purely mechanical and simplified approach is attempted. The reed is modelled by finite elements and a simulation of free static bending shows that the longitudinal flexural stress dominates the problem. By targeting a stress field on different areas of the reed, it is observed that the strain is mainly longitudinal and only slightly lateral, due to the strong anisotropy of the cane (Arundo donax). Thus, a bending moment imposed on the axis of the reed causes almost no translation of the edges of the reed. A local decrease in thickness causes a localized increase in curvature, when the stress field remains constant. With this result, a series of ClaripatchTM was developed to impose a localized decrease in curvature on the mouthpiece’s lay. Using these patches and assuming some hypotheses based on observations, simulations and on the viscoelastic properties of the reed, one can deduce how to scrape it, according to the musical preferences of the clarinettist.06 - Präsentation