Validation expérimentale du modèle de calcul en calotte sphérique des plaques circulaires minces sous l'effet d'un gonflement hydraulique / Experimental validation of a spherical model of circular thin plates under hydraulic pressure

The spherical model constitutes the base of theoretical analysis of circular thin plates under hydraulic pressure [3]. The advantages of this model are the simplicity and the easiness in exploitation and interpretation. Indeed, if the height of the pole and the radius of the die are available experimentally, the stress and strain distributions can be derived analytically. In this study, we present an original experimental technique necessary to validate the spherical model [A. Boulila, Étude expérimentale et modélisation numérique du gonflement hydraulique des plaques minces, DEA de Mécanique Appliquée Option Construction et Fabrication Mécanique, École Nationale d'Ingénieurs de Tunis, Tunisie, 2000]. We show in this paper that the bulge test is a reliable test for characterizing ductile materials (stainless steel 304, aluminium A5 and copper). The comparison of our results with the available theoretical models shows that the studied materials obey the Ludwick law [K. Jendoubi, A. Boulila, A. Elhadhri, Les biomatériaux en Tunisie - Moyens et perspectives, 3èmes Journées M.T. Kassab, Tunisie, Thèmes: Biomécanique du genou et biomatériaux orthopédiques, 12-13 juin, 1998, p. 12]. We show that the bulge test can be used as a technique of forming various types of orthopedic implants (osteosynthesis plates etc.) capable of taking the appropriate anatomic shapes and supply very weak stress concentration factors (Kt).