Abstract

When modelling slender bodies made of composite materials as beams, homogenized stiffness coefficients must be obtained. In [2, 3], analytic expressions for these are obtained by comparing the solutions of some Saint-Venant extension, bending and torsion 3D linear elasticity problems with their corresponding beam theory counterparts. In [2], the authors provide general expressions for the determination of these coefficients for multilayered beams. The present work consists in the study of a homogenization procedure of the stiffness coefficients for circular cross-sections with two layers. This will help in the study of the constitutive behavior of unloaded shafts of endoscopes since their cross-section could be studied as a simplified model of a three-layers hollow circular cross-section. In preparation of this geometry, results of an experimental campaign carried out at KARL STORZ GmbH & Co. KG (Tallinn, Estonia) are presented in a second part of this paper. The purpose of the testing was the experimental characterization of the torsional stiffness of such devices.