Abstract
Starting from the dynamic response of a sandwich beam with damping (which is in free vibration), is established a method used to determine the damping factor. We experimentally calculated the stiffness and damping factor per unit length and unit mass for beams with middle layer made of polystyrene and polypropylene honeycomb respectively; the external layers were made of epoxy resin reinforced with fiber-glass fabric and carbon-fiber fabric respectively. Keywords: sandwich beam, damping factor, polystyrene, polypropylene honeycomb, free vibrations