Mechanical properties of sandwich composite panels

The present investigation aims at studying the mechanical properties of sandwich composite panels at different angular orientation with respect to the rolling direction. The sandwiches were obtained by assembling a polymer core film, 0.4 mm in thickness, between two steel cover sheets, each of them with a thickness of 0.2 mm. Uniaxial tensile tests were carried out at room temperature in order to evaluate the strength-deformation characteristics at different angular orientations. An anisotropic behavior of the sandwich composite was observed; in particular, samples oriented in the 45° direction were characterized by the lowest ultimate tensile strength and highest strain to failure as compared to those in the longitudinal and transverse directions. Finally, the attitude of the hybrid structure to be formed, investigated by mean of the hemispherical punch test, was quantified through the limiting dome height; the high values of the punch stroke at the onset of failure were indicative of the very good formability of the composite panel.