Analyse théorique du comportement mécanique d'une poutre sandwich NIDA en flexion 3 points.

This work presents a theoretical study of mechanical behavior of the HONEYCOMB sandwich beams under three point bending load. The studied beams are obtained starting from sandwich plates intended for the manufacture of Yachts. Two types of sandwich beams are used. Each beam is made up of two symmetrical skins of which the fibres out of glasses are laid out in mat for beam 1 and crossed ply for beam 2. The core consists of polyethylene sheets whose cells are of hexagonal form. The longitudinal and transversal Young modulus of the skins are obtained in experiments by tensile tests, they are used for calculation of the normal and shear stresses. The effects of kinematics, the length to the thickness ratio L⁄h, the core to the skin thickness ration and the longitudinal Youngs modulus of the skin Ep to that of the core Ea ratio on the normal and shear stresses are analyzed. Normal and shear stress results for three different displacement fields are compared. The difference of the results validates the conditions of using simplified Bernoulli and Timoshenko theories for these sandwich beams. [ABSTRACT FROM AUTHOR]