The effect of the viscoelastic film and metallic skin on the dynamic properties of thin sandwich structures

In this work, the influence of design parameters on the dynamic properties of thin sandwich structures composed of micron-size viscoelastic adhesive layers is analysed. Sandwiches composed of different types of viscoelastic film and metallic skins are characterised in the frequency bandwidth of 0-1 kHz. The numerical modelling of thin sandwich structures is presented and validated with experimental results. A four-parameter fractional derivative model is used to describe the dynamic behaviour of the viscoelastic films, and a three-layer beam element is used to model the sandwich structures. The analysis of experimental and numerical results allows the establishment of design considerations to obtain thin sandwich structures with high stiffness and damping. The viscoelastic adhesive film should have a high shear modulus and loss factor, and the metallic skin should have a high storage modulus.